Selected bibliography of NACA-NASA aircraft icing publications

NASA Technical Memorandum 81651

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Selected Bibliography of

NACA-NASA Aircraft Icing

Publications

Lewis Research Center

Cleveland, Ohio

August 1981

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·" .:;;;:nza :p;e .• h< . ac μs!laa, ... ,.4, ._ ..... (4 ·~•<W, .,. --~ :::;.+ •• , +;:W_JU tf.f tAC-WK,.tfQJC ~ ------------ roRBWORD In th-. 1940's and SO'a NACAl was heavily engaged in reaearch -to develop suitable ice protection Mthoda for the aircraft of that period. The work was-conducted both at the Lewie Reaearch Center, Cleveland, Ohio, and at the Aaes Reaearch Center, Moffett field, .! California. NACA devoted several hundred man-yeara of reaearch to the aircraft icing problea. During this sa• period, many others ( in the United States, aa well as in Canada, Europe, Great Britain, i

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\ and Russia were also working on the aircraft icing problem.

In the mid 1950's when the hot-air ice protection system was perfected for the large jet transports such as the KC 135, NACA terminated its large icing program. Lewis, however, continued to make available its 6- by 9-foot Icing Research Tunnel to the air- craft industry for developing and certifying ice protection equip- ment. These testing activities remained at a low level during the 1960's and early 70's. In the last few years, however, the number of requests for testing in the tunnel has steadily increased to the point where the tunnel is now continually occupied.

In the 1978 Aircraft Icing Workshop,2 the recommendation was made that before attacking what appeared to be a new icing problem we should study the icing work of the 1940 1 and 50's. The docu- ments of that period were so old, however, that they were not listed in the modern computerized library search systems, and some

of these documents were out of print. Fortunately, u. H. von Glahn

had prepared a selected bibliography of the NACA-NASA publications in aircraft icing. This bibliography was furnished to those who i ' requested information about the NACA works. But some of the cita- I !

tions in the bibliography were those that were out of print.

I In 1979, both the AGARD Working Group (\«;-09) on Rotorcraft Icing and the Helicopter Icing Panel SAE AC-9 Committee urged NASA to reissue the publications cited in von Glahn's bibliography.

Concurrently, industry and other government organizations requested that these reports be reissued.

The present report was prepared in response to those re- quests. The items contained in this report are as follows:

1. A reprint of a survey article by u. H. von Glahn entitled

"The le ing lroblem: Current Status of NACA Techniques and Re- search." The status report presents the main results of the NACA icing program from 1940 to 1950.

The National Advisory Connittee for Aeronautics, now the National Aeronautics and Space Administration (NASA).

H~ld at Lewis Jeseirch CenterA Clevelan~~ Ohiod July 19-21, 1978. {'Aircraft Icing,' NASA CP-~086, FAA-aw-78-1 9.)

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-*P . SAU,#, 4W)CP ; , •· !fii,jii!U • ..,...,,.. . .......-_,.._~----...,."""'ll-ll!l_,_,..,.....,...._,..,.,...._....,.._•......,--a.,.;--.- -.--- ., ..,.. · e I. 1h Q ,l,, ¼, :;:e...,p 2. A selected bibliography of 132 NACA-NASA aircraft icing

publication, a, 1ub1equently coapiled by u. a. von Glahn. It in-

cludes publication• from 1940 to 1962.

l. A technical aumary of each docuMnt cited in the selected bibliography except for document 132.

4. A microfiche copy of each docu•nt cited in the selected bih'.iography except for docuaent 132. A full-size hard copy or a ,r,h rofiche copy of it aay be obtained from the National Technical ·- .• .:ormation Service.

'111i1 report and each docu•nt cited in its selected biblioa- raphy have been incorporated into UCON, NASA's COllputeriaed tech- nical inforution data bank and are retrievable. Full-1i1e cupie1 of these documents may be purchased from the National Technical Information Service, Springfield, Virginia, with the exception of two reports, 125 and 131. '111ese two are avsilable from the Soci- ety of Aut0110tive Engineers • .l>hn J. Reinmann Lewis Research Center • ii

THE ICING PllOBt.lM - CUUINT STATUS or NACA TECHNIQUES AND llSSIAllCH

By Uwe R. von Glahn National Advisory Coaaittee for Aeronautics Lewis Flight Propulsion Laboratory Cleveland. Chio Icing of aircraft components such as airfoil surfaces and engine-inlet systems similar to those shown in figure l creates a serious operational problem. Aircraft are now capable of flying in icing clouds without diffi- culty. however. because research by the NACA and others has provided the engineering basis for icing protection systems. This paper SWlllll8ri&es some of the techniques used in NACA progras to solve aircraft icing problems and indicates the scope of the data available for the design of aircraft icing protection systems. In addition, appendixes A to C discuss the NACA Lewis icing facilities in detail. specific test equipment and techniques used ~n conducting tests in icing wind tunnels. and several icing instruments.

Icing of aircraft surfaces occurs when liquid cloud droplets cooled below the freezing temperature impinge on a surface that is also below freezing. All surfaces that are exposed to the direct impingement of super- cooled water droplets therefore may require icing protection (fig. 2). The si&e and extent of icing on an airplane component is a function of cloud liquid-water content. droplet size. and air temperature. physical dimensions and shape of the component (si&e, shape, and attitude), and operating condi- tions (airspeed and altitude).

A body moving through a cloud ~f water droplets. in gener~l. will not intercept all the droplets originally contained in the volume of air swept out by the projected frontal area of the body (fig. 3). As the droplets reach the vicinity of the body, the air streamlines flow around the body.

The droplets, because of their momentum, tend to maintain straight paths toward the body; however, a drag force imposed by the relative velocity of the air with respect to a dro;,let tends to cause the droplet to follow the air streamlines. The relative magnitudes of the momentum and drag forces determine the droplet path. The path of droplets in the flow field can be determined analytically with particle trajectory equations. ln order to do this, however, the si&e of the cloud droplets must be known. This informa- tion has been obtained with instrumented airc~aft in flight through icing clouds. Two of the most widely used meth~ds of obtaining cloud icing data are rotating multicylinders and the pressure-type icing-rate meter.

The rotating-multi:ylinder method has been uaed extensively to collact data on both droplet-ei&e diatribution and liquid-water c~ntent in super- cooled clouds (refs. l to 4). The collection of ice by the cylinders i• aimilu to the collection of ice by airplane components. Therefore. the l 'I ........ ~ ....... _, __ ,..

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data obtained by this method have been valuable in designing ici!'lg protec- tion systems for airplanes. In this method, several cylinders of different dian,eter rotating on a coanon axis are exposed from an aircraft i\\ flight or in an icing tunnel to supercooled cloud droplets as shown in figure 4. Dur- ing the exposure period, the cylinders collect ice. The cylinders are rota- ted in order to obtain uniform ice collection around the circumference and thereby to preserve a circular croas section.

After exposure, the diameters ot the iced cylinders are measured and the iced cylinders are weighed. The measurement of droplet size and water content is based on the principle that cylinders of different sizes collect different quantities of ice per unit frontal area. The ice collection of • each cylinder is expressed in terms of a collection efficiency that has bfien obtained theoretically. The liquid water content, average droplet size, nnd droplet-size distribution are obtained by a comparison of the measured weight of ice collected on each cylinder with calculated values of colle~- tion efficiency. The method is applicable only in clouds where the tem?era- ture is below o c.

The pressure-type instrument (ref. 5) operates on the differential pressure created when small total pressure holes plug with ice accretions, as illustrated in the sketch of figure 5, The small total-pressure holes in the ice-collecting element. which are vented to ~tatic pressure through a small orifice. are balanced against a nun-vented, ice-free total pressure in a differential pressure switch. When these small total-pressure holes plug from ice accretion, the pressure in the corresponding side of thP. pressure switch approaches static by bleeding through the static orificP., and a dif- ferential pressure is erected between the iced and ice-free systems. Con- tinuous operation is obtained by allowing the differential pressure switch to energize an electrical heater that de-ices the ice-plugged total-pressure holes. The pressures in the two systems then tend to equalize, opening the pressure switch and allowing the cycle to be repeated. The heat-off time of this cyclic process is used as a measure of the period of time required to plug the holes. This period of time is a function of the rate at which ice accumulates on the element containing the holes because the amount of ice accretion required for plugging is a constant value. The duration of the

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heat-off period is calibrated against a mt'!asured icing rate. An NACA flight-type film recorder is used to record continuously the duration of the heat-off or icing period the heat-on or de-icing period, the indicated air- speed1 the air temperature. and the altitude. The icing rate is ~hen used to calculate the water content of the icing cloud. This instrument is limi

ted by water run-off at air temperatures near o° C and high water con·

tents as are the rotating multi-cylinders. Aho, it does not measure drop I let size. Other icing instruments are discussed in appendix c.

In general, the average droplet size in icing clouds is in the range of 10 to 2S microns in diameter. In atratua clouds the maximum water content is about 1.5 grams per cubic meter, while in cumulus clouds the water content

may be as high as 3.5 grams per cubic meter. Fortunately, these high water content• extend over only a short horiaontal distance. For cumulus clouds the extent of such high water contents is only about 1/2 mile, while for stratus clouds the high water contents U8\,ally do not exceed 10 to 20 miles.

The data obtdned by the rotating-multicylinder method have been of significance in eutabli1hing meteorological design criteria for aircraft icing protection systems. These data, however, were baaed on flights by only a few aircraft in deliberately sought icing conditions. The data from the pressure-type meter have been obtained on a routine flight basis by a cooperative program between the NACA, commercial airlines, and the United States Air Force. Some 50 aircraft were instrumented with these meters in various geographical areas of the world (fig. 6), including the North Atlan- tic, the continental United States, Alaska, the Pacific, and Japan. In ad- dition, the program has been supplemented by in-flight weather reconnais- sance reports from the Air Weather Service and Strategic Air Command air- craft over a two-year period. These data have been put on punch cards and are currently being analyzed on IBM equipment. Because most of the data obtained from routine flights apply to low altitudes, special efforts are being made to obtain data on the occurrence of icing at altitudes above 20,000 feet. Data obtained to date show that icing is rarely encountered about 30,000 feet because of the infrequency of clouds containing liquid water at the low temperatures associated with these altitudes. In addition, the severity of icing encountered above 30,000 feet is usually low except in scattered thunderstorm clouds.

The impingement characteristics and the initial rate of ice formation on aircraft components can be obtained by either theoretical trajectory studies or experimental means, once the water content and droplet sizes of icing clouds are available. Host of the NACA analytical studies of droplet trajectories about various bodies (refs. 6 to 13) utilize a differential analyzer (fig. 7), since experience has shown that even the simplest manual calculations are time-consu,ning and inaccurate. The use of the differential analyzer in this work is described in reference 14.

Typical results obtained from such a trajectory study are shown in fig- ure 8, in which the local impingement rate on an airfoil is plotted as a function of surface distance from the leading edge. The data shown are for a 15 percent symmetrical airfoil of 8-foot chord, angle of attack of zero, airspeed of 150 knots, and average droplet sizes of 8 and 15 microns. The greatest impingement occurs at thP stagnation region and decreases rapidly with surface distance from the leading edge. An increase in avecage droplet size from 8 to 15 microns increases the local impingement rates and causes the impingement area to extend farther aft than with the smaller droplets.

The differential analyzer is difficult to use for droplet trajectories about bodies with complex air flows. Therefore, a wind-tunnel method using

a dye-tracer technique (ref. 15) ia ~ften wsed to obtain experimentally the droplet impingement on these bodiea. In thia technique (fig. 9). water treated with known small quantitiea of water-aoluble dye ia aprayed into the airatream a large distance ahead of the bodv by noza~es. The aurface of the body is covered with blotter papdr upon which the dyed water droplets im- pinge and are absorbed. At the point of droplet impact. a permanent dye trace is obtained. The amount of dye obtained in a measured time interval can be determined by a colorimetric analysis of puncned-out aegments of blotted paper (fig. 9) and converted into the quantity of water that pro- duced t:he dye trace. The maximum extent of impingement of the local dye or water deposit over the entire wetted surface will yield the total amount of water collected by the body. !hie experimental technique requires a know- ledge of the droplet-size distribution and water content of the spray cloud. Methods of obtaining these parameters have been worked out and are included in the report concerning the technique (ref. 15).

The total water catch and the extent of impingement on an airfoil sur- face obtained by the differential analyzer are compared in figure 10 with the experimental data (unpublished). These data are shown as a function of an impingement parameter which. in this case, depends primarily on the drop- let si&e squared, wing chord, and airspeed (ref. 16). These are typical results for a 15 percent-thick symmetrical wing at zero angle of att~ck.

From a knowledge of the droplet impingement characteristics and meteor- ological parameters, the local water impingement rate or icing rate on com- ponent surfaces can be calculated. Unfortunately, the shape of the result- ant ice formation, which has a large effect on the aerodynamic penalties associated with component icing, can only be estimated based on limited ex perimental data, since the ice-formation shape is also a function of airfoil sweep angle, air temperature, and aircraft speed. Ice shapes can be gener- alized into two primary shapes, rime icing and heavy glaze icing (fig. 11).

Rime icing is associated primarily with low air temperatures and results in relatively streamlined ice formations that blend into the body shape and cause little aerodynamic penalty. Heavy glaze icing results £rom high water contents, large droplets, and surface temperatures near freezing. This com- bination of meteorological conditions causes rough ice formations that protrude from the body surfaces into the airstream and cause large 4erodynamic penalties.

Early attempts to measure these penalties were made in flight through icing clouds. However, the general advantages of doing icing research in a tunnel where conditions can be controlled were recognized, and an icing re- search tunnel was built at the NACA Lewis laboratory. The Lewis icing tun- nel is a single-return closed-throat tunnel, the general arrangement of which is shown in figure 12. The test section is rectangular in shape, 9 feet wide, 6 feet high, and 20 feet long. The maximum tunnel airspeed with

-,.,.-~~- ..... •-•4411111:llll'c•-, ........ ~-~~--- ,., , -~,~,....,...,..,.._ __ 1c1na condition• and with a larae model in the teat section i• about 260 knots. Air temperatures a1 low a• -40° C can be obtained, although moat te1t1 are conducted in the range of -3~ to -20° c.

Icing conditions similar to thoee encountered in the atmoephere are created by a battery of air-water atomizina nozzle•. A view of the spray eystem looking dt'Wnstream into the test section is shown in figure 13. The spray nozzles are mounted in six horizontal spray bars and located to give a uniform cloud approximately 4- by 4-feet in the test section. This cloud conforms to natural icing clouds measured in flight. Details of this icing tunnel, its equipment and instrumentation, as well a• of several high-speed icing duct tunnels, are given in appendixes A and 8.

In order to determine the magnitude of the aerodynamic penalties asso- ciated with icing of lifting surfaces, airfoils of different sizes, thick- nesses, and shapes were tested in the Lewis icing tunnel over a wide range of angles of attack and icing conditions (refs. 17 and 18). Section-drag measurements during icing were obtained by means of an integrating wake sur- vey rake (fig. 14) and the tunnel force-measuring balance system. Lift and pitching moments were also measured with the balance system.

A typical lift and drag curve for an NACA 0011 airfoil at an angle of attack of 2.3° is shown in figure 15 as a function of time in glaze icing, together with a picture of th,t ice formation at the end of 18 minutes of icing (unpublished data). It is apparent that under these operating condi- tions the loss in lift of 12 percent and the increase in section drag of 270 percent after 18 minutes of icing could constitute a serious problem for an aircraft.

Ice formations on aircraft components can be prevented by flowing or spraying temperature-depressant fluids over the component surfaces (ref. 19) or by heating the surfaces (refs. 18 to 23). The work of the NACA has em- phasized the use of heat for icing protection. Component icing can be pre- vented by thermal means in two ways: (1) The surfaces can be rdised to a temperature just sufficient to maintain the impinging water in a liquid J state over the entire surface, or (2) the surf3ces can be supplied suffi·

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cient heat to evaporate the impinging water in a specified distance aft of the impingement area while the remainder of the surface is unheated. 0bvi· ously, it takes more heat per unit surface area to evaporate the water than to maintain the r,ame surface just above o c. Calculations show, howev~r

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(ref. 23), that the total area that requires heating must also be considered

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in evaluating the total heat requirement. Therefore, the size of the compo- nent will generally influence which of the two methods of ice prevention is used.

The ~aat aupplied to a component fot icing protection (fig. 16) warms the impinging water to· the component surface temperature and evaporates part or all of the impinging water. Some heat is lost to the ambient air by con- ···---• ----· • .... 0 -- ht e +

----~- ~-.-;~--- """"""'!WW!M-Zll!I)_.~- vection. The relative magnitude• of the external heat loaaea shown in fia- ure 16 are typical for anti·icina a wina surface and are shown aa a function o! surface distance aft of an airfoil leadina edge. In addition, aome of the heat ia loat to adjacent structure by conduction. The external heat- tranafer proceaaea from a heated, wetted surface were postulated by J. K.

Hardy (refa. 24 and 25). The processes were aubatantiated by in-fliaht Jata obtained by the staff of the NACA Ames laboratory (ref. 20). The AM• teats employed an aircraft with ele,trically heated dorsal winaa (fig. 17). The electrically heated airfoils were instrumented with thermocouples (fig. 18) 10 that, with the conductivity and thickness of the material known, the in- ternal heat loss could be calculated. Because of the thin outer skin, the chordwise heat conduction was considered negligible. Hence, the external local heat transfer was obtained from the total power input and the internal heat loss.

Typical results obtained from these studies are shown in figure 16.

These data show that the heat for evaporating the impinging water and that lost to the ambient air by convection are approximately equal. The heat required to raise the impinging water to the surface temperature is only a small fraction of the total heat input. At the leading edge the heat flow is about 3900 Btu/(hr)(sq ft), while aft of the impingement area the local heat flow is 2400 Btu/(hr)(sq ft) or less.

In order to demonstrate that the results obtained in icing conditions in the tunnel were the same as those obtained in flight, a wing section car- ried on the C-46 aircraft during the Ames laboratory flight te~ts was also tested in the icing tunnel, and the data were compared (ref. 21). The re- sults showed that in similar icing conditions, as determined by measurements of the cloud conditions by simil~r instruments, the data agreed satisfactor- ily.

For high-speed, high-altitude aircraft, the icing-protection heat re- quirements (due to changes in heat transfer and evaporation considerations influenced by speed and altitude) of a thermal anti· icing system are exces- sive. For example, calculat:ons showed that the heat required for evapora-

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ting all the water impinging on a jet powered transport exceeds 7,000,000 l Btu/hr. Since this heat would be taken from the jet engines, a severe per- • formance penalty would result (ref. 23).

In order to reduce the thermal requirements for airframe components, cyclic de-icing systems were studied. In cyclic de-icing, ice is permitted to fonu on the airplane surfaces and is then removed periodically by a short intense application of heat. During the heating period, the bond between the surface and the ice is melted and the i,-! is removed by aerodynamic for- ces. Only a few components or sections of a component are heated at a time, the rest being allowed to ice. Because the components are heated succes- sively, proper grouping of the components permits shifting of heat from one group to another and thereby maintaining a conatant heat load. The i~ing or heat ~ff time is determined by the amount of ice that can be tolerated on a component without seriously affecting its performance.

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_.,. m WWW# -iA-4 •• Numerou1 thermal cyclic de-icing 1y1tem1 were 1tudied in the Lewie icina tunnel, typical of which wa1 the hot 1a1 cyclically de-iced airfoil 1hown 1chematically in fiaure 19. The initial NACA de1i1n ~on1i1ted of a conventional double akin, a t"fO-way hot aa• 1upply duct with valve• for cy clina the hot aa• into the plenum or D-duct running 1panwi1e at the leadina edae, and a cond~ctina fin attached to the 1upply duct and airfoil akin at the leading edge near the 1tagnation region (ref. 26). A two-way ga11upply duct wa1 u1ed 10 that the hot aa• would flow outboard and return in an ad joining rear pa11age in order to maintain a con1tantly hoc 1upply line. The valve• in the 1upply line open in 1panwi1e 1equence, therebt fermitting a con1tant flow of ga1 in the forward paaaage and greatly avoid1n1 thermal laga. Because the forward passage ia continuou1ly heated, the fin conduct• heat to the akin at the atagnation region, thereby providing a narrow ice- free apanwiae parting atrip. Thia ice-free parting atrip aplit~ the ice cap that uaually form• over the noae of the airfoil and facilitates ice removal by aerodynamic forces during the heating period.

The model was extensively instrumented with thermocouples in the akin and structural members and in the ai~ passage• in chordwiae planes at several apanwise locations. Flow to the various sections was canfully metered by orifices in the air-supply lines. Timing of the fast-acting pappet-type cycle valves was made with electronic timers.

The results obtained from extensive studies of this model (refs. 26 and 27) show that savings in total heat input of as much as 75 to 90 percent of the heat required to prevent ice on t.he same wing were achieved. Similar results were obtained at both the NACA (ref. 28) and NAE facilities with electrically de-iced airfoils. Subsequent atudie~ with a 36° swept wing (ref. 17) show that the tangential air-flow component along the span is auf ficient to eliminate the need of a spanwiae ice-free parting strip for facilitating removal of the ice forlll8tion. Systems similar to the NACA hot- air cyclic de-icing systems are currently being used by some manufacturers in the latest jet aircraft.

The use of a cyclic de-icing system necessitates an evaluation of the aerodynamic penalties associated with the ice formations permitted to build up during the unheated portion of a cycle (fig. 20). A number of airfoil models were teated to obtain the drag characteristics of cyclically de-iced airtoils in icing conditions (refs. 17 and 18). The results of these teat• show that the drag and lift change• averaged over a cycle do not cobatitute a serious oper4tional hazard if the length of the cy~le can be adjusted to the serverity of the icing condition.

In addition tr.- thermal de-icing aystems, ice can be relllOved from moat airfoil surfaces by a mechanical de-icing system consisting of a high- pressure pneumatic boot (fig. 21). In this system, inflatable tubes are sandwiched between two layers of rubber or neoprene. When ice forms on the outer surface of the boot, compressed air is bled periodi~ally into the tubes which then inflate !~r a period of 3 to 6 seconds. Vacuum is applied

w ... WWW- SW .,,. ..

to the tube• to maintain the surface flu1h durina the off part of the cycle. Studie1 in the icina tunnel 1how that th••• de-icer, will effective- ly r8110ve the main ice forution•: however, the ••11 fl•~•• of re1idual ice adhering after the removal cycle will cau1e a aect1on-drq increaae of up to about 30 percent (unpubliahed data). !xperiMntal 1tudiea indicate that removal of the•• re1idual ice fonaation1 by 1ubli•tion i• a lona procea1 (ref. 29). Th••• drag increa1e1, therefore, can penalise aircraft perfora- ance over a much longer portion of the entire flight than for juat the dura tion of th~ icing encounter.

The engine i• the moat vital component on the airpla~e requ1r1na icina protection. Work on icing protection for engine air inleL1 and induction 1y1tem1 covered pi1ron and jet engines. The work on pi1ton enaine1, 1uana- riaed in an NACA technical report (ref. 30)~ led t~ the recOlllllendation1 in- corporated in figure 22 for a typical arrangement of a~ engine induction 1y1tem. Such a de1ign includea (1) an air inlet, which r3duce1 the intake of water and snow to a miniaum by utilizing the inertia and momentum ditf4r- ence, between air and water particle• to aeμarate the dropieu out of the air at the inlet, (2) aerodynamically clean flow pas1age1 to prevent ice accretion on exposed parts, (3) air-metering device, located in a wan, dry region,·(4) throttle and throttle bodie• kept above freezing, and (5) fuel injected down1tream <1f the heated surface• to prev~nt fuel-evaporation icing. Aircraft that incorporate many of the1e feature,, including the inlet type ahown, are the Convair~40 and some ver1iona of the Lockheed Con- stellation.

The high speeds of jet-powered aircraft •nd the large engine air flow1 nece1sitated a reapprai1al of the icing problem for jet engines compared with that for the reciprocating engine. While the early centrifugal jet engine• were not generally critical with re1pect to inlet and engine icing, becau1e of engine get'lllletry and structure, the axial-flow engine, were ad ver1ely affected by icing. The icing of engine inlet guide vane• (ref,. 31 to 33) and inlet 1creen1 constituted an icing hazard (fig. 23) that not only reduced the available thru1t and increa,~d 1pecific fuel c~n•umption but could cauae engine fQilure. The icing hazard of• fixed inlet 1creen was aptly demonstrated by the simultaneou1 1011 of eight F-84 aircraft over Indiana after a brief encounter with severe icing c~ndition• in 1951. Teet• in the Lewis icing tunnel also showed that the pre11ure 1011 •••ociated with icing of guide vane• could cau1e large pres•ure lo11e1 and hence thrust lo•- ae• (ref. 33). Several icing protecti~n 1y1tem1 u1ing alcohol or hot aa• injection into the airatren to provide protection for the 1creen, acce••ory hou1ing, ar.d guide vanes were 1tudied by NACA and NAE. With these 1y1teu, however, contamination of the compre11or air (which i, often used for cabin pre1surization) or large thrust lo11e• re1ulted.

The u1e of thermal icing protection for 1101t engine component• appeared 1101t fea1ible. In the ca1e of the 1creen, howew.r, electro-thermal •an• did not appear attractive b1cau1e uf the lara• heatina rate• required. Coo- 1equently1 the complete elimination of the acreen or retraction during an ,J

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,, i :1 ,, icina •nc~unt.er appeared aan4atory. lliaination of the 1creen ex,oaed the • i •naine to daaaa.a frOl& ic• chunk• breakina off from unprotected coaponenu '.

ahead of the coapre,aor and ent•dna the •naine. Practically all typea of axial-flow •naine1 teated at the ailitary 1ervice1 Mt. Waahiqton icina fa- cility have 1uffered partial or coaplete •nain• failure froa inaeation of 1uch ice chunk,. Theraal icina protection i• required, therefore, for all coaponenta of the •naine inlet that uy 1hed th••• ice chunk• if left unpro- tected.

In the axial-flow enaine the inlet auide vane• upatr•• of the coaprea- ' aor ice quickly. Coaplet• icina protection of th••• ... ber1 i1 required if l th• •naine ia to function in icina condition,. A atudy of Man, for beatina .l 'I the auid• vane• internally with bot air va1 conducted with a ca1cade of five van•• 1110unted in - rectanaular duct ••tin th• icina tunnel (fi&• 24). lee collected on the ~~•dins and trailina edae• of the hi&hly c•b•red blade• uHd for inlet 1·.aide vanH. For thia reHon, a aavina of SO percent of the heatina air flo" Ciia. 25) ii achieved if the interior of the vane ia parti- tioned to re1tr:·.ct thb bot air to the area, of the blade on which ice col- lecta. Thia partitioning of guide vane, ha1 been adopted for aoaae current enainea.

Becauae the engine acce11ory dome collect• ice that aay break off after reachina a de1tructive aize and ent•r the engine, reaearch wa1 conducted on the hHtin& requireMntl for Hveral jet-engine acceaaory doaea. An elec- trical icina p~otection 1y1tea waa uaed in order to obtain ,elective and controlled heatina and th•reby verify theoretical local heat-tran1fer data (ref. 22 and unpubli1hed data). The doeea were teated al10 with rotation to ai•late turboprcp in1tallation1 in order to atudy the effect of rotation on heating requireMnta. In geueral, the rotational effect waa negligible for the ai&e aodel• teated.

While it ia apparent that aircraft operatina at relati~ely low air- 1peed1 and at altitude, le,, than 20,000 feet will requi~e airframe icina protection equipment, high-1p1ed, hiah-altitude aircraft, on the other hand, may reqcire little if any 1uch equipment. These aircraft crui,e at alti- tude• where little or no icing occur,. Studie, in high-1peed icing duct tunnel, (ref,. 34 to 36) •how that icina can occur at 1peed1 up to a Mach number of approxi111<2tely 1.3; however, becau,e of aerodynamic heatina of the aurfar.es at this high speed, auch icina condition, would require low air teaaperatures. The frequency of encountering severe icing at low air temper- ature, on a statistical probability ba1i1 ie almost negligible. The icina problem for theae aircraft, therefor~, i• confined primarily to climb and l*t down condition,. Becauae of their hi&h rate, of. ••cent and deacent, the icing encounter• for these aircraft are of ahort duration. Conaequently, the fliaht plan and aircraft mis,ion are l:>ecoaing increa,inaly tDOre impor tant in determining the neceaaity for airframe icing protection equipment.

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A li • ited operational analy•i• of an interceptor alld a tranaport air craft vaa preae1nted in a peper by Lhe author at an NACA conference on IOIN Probl•• of Aircraft Operation (Nov. 17-18, 1,54). Thi• atudy ahowd that thin-viqed interceptor aircraft with a hiah rate of clillb and deacent and cruiaina at hiah altitude do not appear to require an airfrAM icina protec-

tion •Y•t•• except po1aibly durina a landina operation. Thia 1tudy •uu-•-

ted ~r,at a partial or a aiaple one-1hot icina prot•ction •Y•t• could be inatall,d at minimua weiaht, 1tructur1l, and perforunce penalty to cope with an icina encounter durina landina. Th• 1tudy al10 concluded that jet tran1port1, b1cau1e of their alower rat11 of a,cent and d11c1nt, 1hould be provided with an airfra111 icina protection 1y1t ... Since the enaine it 10 vulnerable to ic• damage, complete enaine protection it r•quir1d for both type• of aircraft.

ln ,u ... ry, therefore, the NACA r111arch prog~au have provided 1uffic- • ient data or have 1arabli1h1d t1chniqu11 whereby icin1-prot1ction requirr 1Nnt1 for moat aircraft compon1nt1 car. be d1t.1nain1d 1ufficiently accurately for engineerina purpo•••• The data obtained have been generalised whenever po11iblei however, it i• r1co1nis1d that certain 1pecific in1tallation1 at pr111nt ,till require teatina in an icing tunnel or in fli&ht. Neteoroloa- ical 1tudi11 are providins 1uffici1nt information on condition• conducive to icina on which to ba11 the d11ian requirement, of aircraft c0111ponent1 and to determine the need of icina protection for 1p1cific airC!raft and fHaht plan,. While thi1 paper deal1 priurily with NACA 1tudi11 in icina r..- 11arch, the contribution, of other a1enci11 includina the 1roup1 operatina at the Mt. Wa1hin1ton facilitie1, the U.S. military e1tabli1h•nt1, the

u. s. aviation indu1try, the Canadia~ NAE, and other 1roup1 in the United

State,, Great Britain, and France mu1t al10 be r1co1nis1d. All th••• 1roup1 have cooperated and ••changed idea, that have aided in the 1ucce11ful solu- tion of many icing problema.

• • .j.,

-- ~ ·~ _........-- -- - -- - l'J ... ,. __ _,,,,... ... ____ .., ____ .., ... _.,_, ____ ,~_,,,_,....._...,. __ ~-~----- .. , -----""""'·' .... ---------~-""*""----""-----·-,- 'i : .. i ·' APPENDIX A I ,1 l ICING TUNNEL FACILITIES :1 ,: The amount of time required for both aircraft and equipment maintenance to obtain sufficient data in flight toward the solution of icing problems, together with the difficulty of obtaining data in specified, controlled icing conditions, resulted in the design and construction of an icing wind tunnel at the NACA Lewis laboratory in 1943-1944.

The Lewis icing tunnel ia a single-return closed-throat tunnel, the general arrangement of which is shown in figures 12 and 26. The tunn~l ia constructed of steel plate and is insulated with a 3-inch thickness of Fi- berglas. The outer nonstructural shell covering the insulation is made of 1/8-inch steel sheets.

The tunnel is anchored at each end of the test section and at each end of the drive motor and supported by columns an~ sliding expansion joints at all other points in order lo allow movement due to temperature stresses.

The over-all size of the tunnel shell is about 198 feet long and about 75 feet wide. The test section and a portion of the entrance cor.e and diffuser ar .. , surrounded by a steel housing to provide spdce for the essential test equipment and operating personnel. This space is called the teat chamber.

Because the test section is vented to the chamber, the air pressure decrea- ses in the chamber during operation of the tunnel (norm~lly less than 3 in.

Hg). An air lock is provided lo permit access by personnel to the chamber during a run.

The test chamber contains three floor levels: the ground floor, con- taining electrical, thermocouple, water, and balance-scale equipment; the second floor, containing the test section of the tunnel and the various con- trols, manometers, recording instruments, and associated equipment; and the third floor, containing auxiliary measuring equipment. Personnel access to t~ tunnel is generally from the second floor of the test chamber, while models are lowered into the test se~tion from the third floor through a re- movable 48- by 140-inch access hatch 1.n the roof of the test section.

The test section is rectangular in shape, 9 feet wide, 6 feet high, an<l 20 feet long. The air enters the test section from a large rectangular sec- tion g1.v1ng a contraction ratio of about 14 to 1. The test section of the tunnel is provided with a turntable on which models can be mounted, as well as side-wall trunnion mounts. The maximum tunnel airspeed with iring condi- tions and a large model in the test section is 260 knots.

Windows are provided on both sides and in the r~of of the tunnel test section to allow observation of models during a teat, The windows in the tunnel sides are laminated, electrically heaLeJ units similar to windshields

b 4 -~·------_. ........ .....,_~-~-· ·- -- ... -- .- .. ~· -,· -

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f on •ny aircraft, while the windows in the teat 1ection roof are unheated.

The power supplied to the new window, currently being inatalled i1 500 watt,

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per 1quare foot. The teaperature of the pla1tic inner layer of the window is detected by a nickel wire element. Thia element is used in a bridge cir-

~

, ' cuit to control the window temperature.

Turning vane, are u1ed in all right-angle corner, of the tunnel. The vane• downatream of the teat section and ahead of the drive fan are ateam- heated to prevent icing.

The drive motor for the tunnel develop, 4160 horaepower. The drive con1i1t1 of a doubly fed wound-rotor induction aotor. Power i1 supplied directly to the 1tator, while the power for the rotor ia aupplied by a four- machine variable and fixed frequency setup. A variable-apeed d-c motor, driven according to the Ward-Leonard syatem, drive, an a-c generator. The • generator 11appliea the power to tile tunnel drive-motor rotor. The speed of the dTive motor is governed by the speed of the a-c generator or d-c motor, the apeed of these machines being controlled by varying the voltage to the d-c motor. The drive motor has a speed range from Oto S40 rpm. A 200,000- cubic-foot-per-minute, SO-horsepower blower is used to cool the dri~e motor.

The tunnel drive motor is coupled directly to a 25-foot-dia11eter drive fan with 12 blades. The {an blades are wooden, with the leading edgea of the blades protected by neoprene abrasion shoes. Stationary contra-vanes are used ahead of the fan.

A ventilating tower is located downstream of the drive motor. Thia tower permits an exchange of tunnel air with outside air. The primary use of this unit has been to provide an additional cooling load to help regulate the tunnel air temperature for certain teat conditions. In addition, a

finned-tube heat exchanger with a capacity of S,000,000 Btu per hour is I

, available to aid in regulating the tunnel air temperature.

l A compression-type refrigeration system located in a nearby building is used to cool the tunnel air to the required icing condition. The tunnel is cooled by passing the air over a bank of refrigerated finned heat exchangers located in an area between the drive motor and the tunnel spray system. The total refrigeration capacity is about 7700 tons. The nonul cooling load for th~ icing tunne.l requires from 1200 to 2100 tons; however, this require- ment varies with climatic conditions. Air temperatures as low as -40° C can be obtained, although moat tests are conducted in the range of -3° to -20° c.

Icing conditions similar to those encountered in the at110sphere are created by a battery of air-wateT atomising no11le1. A view of the spray system looking downstream into the test section i • shown in figure 13. The 1pray no11le1 are mounted in six horiaontal •pray bare and located to give a uniform cloud approximately 4- by 4-feet in the teat section. Controls for the spray »yatem are located in airfoil-shaped enclosure• at one end of each strut.

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A sketch of the air-water atomiaing noaalea used in the spray 1y1tem ia ahovn in figure 27. 'lbe noar1e aaaembly con1i1t1 of air and water 1upply line,, ateam line to prevent icing of the entire strut, and the 1pray noaale (lnconel). Approximately 80 noaalea are used to obtain an adequate cloud in the tunnel. The noaalea were specially developed for the tunnel to yield droplet aiaea ranging from a mesn effective aiae of 4 micron• at low waler flow, to about 20 micron, at maximum water flowa. Air preaaurea of 60 to 80 pounds per aquare inch are uaed normally to atomiae the water, while th~ water preaaurea range from a few pounds above the air-pressure values up to 140 pounds per square inch. The large water-pressure values correspond to large water flows and large droplet sizes. The droplets produced by these noaales are not uniform in siae but vary approximately in accordance with a Lanpuir Dor E drop-size distribution (ref. 37). For a constant water flow, the liquid-water content in the tunnel varies with the airspeed. In

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addition, the contraction of the tunnel entrance cone affects the droplet • paths and local water concentration in the tunnel. Consequently, maximum or minimum values of water content and droplet size independent of tunnel air-

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speed cannot be stated explicitly.

The water used for the spray system passes through a 500-gallon-per- hour-capacity deminerali&er. The demineralizer consists of two Anion and cation filter beds that remove all minerals from the water, thereby prevent- ing fouling and plugging of the spray system. From the demineralizer, the water is piped into a storage tank with a capacity of 750 gallons. The storage tank is kept full by a float switch that turns the deminerali1er on and off to maintain a given water level in the storage tank. From the stor-

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age tank the water is piped to two turbine water pumps with a capacity of 5 1 gallons per minute each at l~O pounds per square inch gage. The wate~ is pumped through three rotameters for flow mesasurement and then into a steam

heat exchanger that heats the water to a temperature of 80° to 90° c. j

Keating of the water is necessary to prevent freeze-out of the water when it j is air-atomi1ed to cloud droplets in the tunnel. Following th~ heat exchan- ger the watet is filtered at each strut control box. The water pressure is regulated at each strut by a pressure regulator controlled by the tunnel operator. The water pressure is sensed by a pressure transmitter, which changes water pressure to pneumatic pressure. The water pressures in each spray strul (in the form of pneumatic pressure) are indicated on a manometer board in ~,,t) test chamber.

Air is furnished to the water-spray system from a service air line with a capacity of b pounds per second at 120 pounds per square inch. This air is passed through a pressure regulator, a steam heat exchanger (which heats the air to approximately 80° to 90° C), and a two-stage filter before entering the strut control boxes. The air pressure is also controlled from the test-chamber control area.

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A separate spray system consisting of 4 to 9 noaales is used to inject dyed water into the tunnel for experi•ntal studies of droplet impinge•nt characteristics of various bodies (ref. lS).

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l A balance frame is provided with a 6-coaponent force-measuring scale syetem. Data are recorded automatically on tapes at each balance. Electri- cally heated co-axial pres,ure tubes are used to obtain pressure data. All pressure data are recorded photographically from multi-tube uno.ter boards. Temperature data obtained with copper-constantan thermocouples are recorded on automatic flight recorders. The control equipaent includes var-

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iable transformers for power control to models, automatic temperature con- , troller for heated air to models, and various recording instru•nts for • heat-source control. Standard instru.nts are used to record tunnel air- speed and air tem~erature. An NACA pressure-type icing-rate •ter is used

~

to measure the liquid-water content of the tunnel atmosphere. Special in- • strumentation is added whenever required for a particular study.

Heated air for providing models with icing protection is supplied by three heat exchangers. The air from these exchangers is heated by the ex- haust from a jet-engine combustion can. Each heat exchanger has a flow ca- pacity of 1000 pounds per hour with pressure regulation up to 120 pounds per square inch. Orifices in each line allow a measurement of the flow from each exchanger. Conotant air temperature over a wide range of air flows is obtained byan automatic flow control that regulates the amount of cold air permitted to mix·with heated air from the exchangers.

Electric heating supplied to models for icing protection can be ob- tained from either a-c or d-c sources; howeve1, a-c is generally preferred.· The d-c system capacity is 28 volts and rated at 100 amperes. In addition, a 12-volt d-c system rated at 50 amperes is also available. A 29-volt a-c system rated at 50 amperes is available and is used for heate~ studies for which the heater load is normally run on d-c. A 110-volt single-phase sys- tem and a 208-volt, three-phase, 50-ampere system are available for large electrical loads. Selective power inputs (a-c three-phase system) to elec- trically heated models are metered (power recorded on a recording wattmeter) by means of 18 variable transformers rated at 3 amperes, 16 variable trans- formers rated at 9 amperes, and 3 variable transformers rated at 45 anr peres. A 400-cycle inverter capable of supplying .500 volt-amperes at 115 volts is also used for some instrument tests.

Electronic timers are available by which specified heating and icing periods for either electric or air heating systems can be controlled.

The 136-inch-high multi-tube manometer board is so arranged that it may operate as an integrating type or a standard board. A total of 298 readings can be obtained from the board. Additional U-tube and standard manometer boards are available as required. Most of the tubes are also connected to an air-purge system by which air is bled through the tubes back to the ,,,,..J

l#AU4 + ' ~~- -~~~---- -- -~-,.,,,..,~~ ....,... ___.....,......, __ _ model. An air-o&Mtrated cylinder or pincher closes off the tubes at the aa- nometer to prevent the purge air from blowing the manoaeter fluid out of the bonds. The purae air prevent, the entry of water from the spray cloud into the tubes and blocking or freeaing of the unheated portions of the pressure lines. Durina thia purging procedure, no manometer-board readings are taken.

For aerodynamic studies of airfoils in icing conditions, the airfoil surfaces aft of the region protected by the icing protection system (called afterbody) are generally heated. This heating is required, since the turbulence level and supersaturated air in the test section cause a frost deposit on the cold portions of a model. These deposits have rarely been observed in natural flight icing. Such frost deposits increase the measured model drag. A steaa line operating at +5 to -3 inches of mercury is used to heat these afterbodies. To avoid steam leakage from the model into the tunnel, the afterbody is operated at a negative pressure by means of a small ejector and a barometric condensor located externally of the model.

Photographs of ice formations during a test are obtained with high- speed electronic flash equipment, while conventional camera equipment is used for pictures taken in the tunnel at the conclusion of a test. Color photography has proved to be the most satisfactory for movie film recording of data in the presence of the spray cloud.

Airfoil models normally span the vertical height of the tunnel. Chords of these models have ranged from 13 to 96 inches or larger. Horizontal model mounting has also been used occasionally; however, because of wind- tunnel-wall interference effects, the vertical mounting is preferred.

Bodies of revolution and inlets tested are normally less than 36 inches in diameter.

In addition to the 6- by 9-foot icing tunnel, two smaller high-speed icing-duct tunnel facilities are also used. Techniques equiv&lent to those just described are used in these tunnels. A schematic diagram of tli~ 3.84- by 10-inch tunnel presented in figure 28 shows the inlet diffuser sectio.1 with screens, the plenum chamber with flo..,..s t raightening tubes, th~~ bell- mouth tunnel entry, the test section, and the outlet diffuser section. The tunnel is designed to provide a range of subsonic Hach numbers from C .. J to 0.8 and a supersonic Mach number of 2.0. Altitudes up to 30,000 feet may be simulated.

A supply of refrigerated air initially at approximately -20° F and with a specific humidity of 5.0xlo- pound of water per pound of dry air is conditioned to provide the desired temperatures and humidities at the tunnel test section. The humidity of the airstream is co~trolled by means of steam injected at a point sufficiently far upstream to ensure thorough mixing at the tunnel entry.

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One wall of the tun~el contain, a larae 1la1a ,action for obNrvation and vi1ual aeaaure•nt1. The other wall baa fift porthole, for ace••• to the in,ide of the tunnel and reaovable plua• for in1tallation of inatruaen- tation at variou1 1tatiou along the tunnel. Peraaneat in,trwaantation of the tunnel at the teat 1ection includes 1tatic•prea1ure tap, alona the to, and bottom 1urfacee of the tunnel and prea1ure taps and theraocouplea in the plenWll chaaber.

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' A acheutic diaaram of the coaponent part, of a 12- by 12-inch icina duct tunnel is shown in fiaure 29. The tunnel characteriatica are in aener• al similar to the 3.84 - by 10-inch tunnel. Subsonic apeeda up to• Mach nuaber of 0.75 can be achieved with ••11 airfoil models. For icina studies

f

the airspeed ia .. intained in the aubaonic and low supersonic apeed rans•••

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I APPENDIX B

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OPERATIONAL TECHNIQUES The following are techniques uaed for model teating in the Lewis icing tunnel and associated f~cilitiea.

Thermocouple Installations I.

' ~ Whenever posaible, all skin or surface thermocouples (copper-constan- tan) are peened into small holes drilled into the aurface as ahown in figure 30. The ball at the junction of the thermocouple is juat large enough to fit into the hole, so that peening the surface around the ball will result in a firmly anchored ther1110couple. The ball should be as close to the outer surface of the skin as poaaible. For very thin metal skins (O.OOS-inch stainless ateel, e.g.) spot-welding the thermocouple on the inner surface of the skin is acceptable. The thermocouple leads should not be secured on the outer surface of the model, since ice will anchor on the leads. If splicing of thermocouple leads is required, such splices should be made in a protec- ted, constant-temperature location, outside the model in the test chamber.

All thermocouple leads should be protected against moisture; asbeatoa- covered wires are not generally recommended for models in icing conditions.

Shielded thermocouples are recotnmended for obtaining measurements of hot air temperature, although a trailing thermocouple such as that shown in figure lO(u) is acceptable.

Tunnel Air Temperature The tunnel air temperature is obtained with a probe that separates th~ entrained water from the airstream as shown in figure 31. The probe con- sists of a nose and rear cap and a housing containing a temperature-sensing

element. Hol~s are located in the housing so that the air flows through the J

j probe from the rear to the front of the probe. The locations of these holes are based on pressure-distribution studies. The water droplets, because of

H

their inertia, do not enter the housing at the rear locations. Secause the I'

nose-cap diameter is larger than the housing diameter, the housing is pro- d

tected from icing. The nose cap is allowed to ice. Thermal icing protec- J tion could be incorporated in the nose cap; however, an error in the indica- l ted temperature would be incurred. The average. temperature-recovery factor j for these probes is about 84 percent and is constant over a range of Mach t numbers from 0.2 to 1.0. In the NACA icing tunnel the probes are used to measure air temperature in the low-speed section upstream of the spray sys- tem and ahead of the contraction cone. The air temperature measured by thes• probes is therefore essentially a total air temperature. Because the tunnel is always at least saturated when the sprat system is used, the ambi- , ' i

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i ent-air temperature in the teat section ia computed by conventional wet-air equations (ref. 21). '111e total air temperature measured in the low-speed section of the tunnel is used for a baae in theae calculations.

Temperatures from Rotating Bodie• A typical means used to transmit the temperatures from a rotatina body to a recorder ia shown schematically in figure 32. The thermocouple lead•

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from the body are fed through a hollow motor shaft to the rear of a motor hou1in1 and throuah a thermocouple selector switch into a steam-filled jack- et that rotates with the shaft. From the rotating jacket, copper lead1 are

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attached to a slip-ring and brush assembly. From this a1sembly copper leads are again led into a steam-filled stationary jacket. Copper-constan- • tan leads are used from the stationary jacket to a thermocouple selector

r unit and to a fli3ht recorder. The steam jacket is used to provide a con-

stant temperature at critical junctions in the thermocouple circuit, where

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• r the wire metal in the thermocouple leads is changed from copper and constan- I tan to all copper and back again.

Pressure Tubes In icing conditions all pressure tubes subject to water impingement !

(pitot-static tubes, tubes in survey rakes and in the boundary layer, etc.)

must be protected against icing. In the Lewis icing tunnel such pressure tubes are generally electrically heated. A co-axial tube is used consisting of two concentric tubes separated by a woven glass sleeving insulation (fig. 33). The ends of the tubes exposed to the airstream are silver- soldered and shaped to obtain either static or total-pressure tubes. Tube sizes of 0.093- to 0.437-inch outside diameter and 0.057- to 0.393-inch in- side diameter with wall thicknesses of 0.005 inch are in c0111UOn usage.

These tubes are made of lnconel. A special tube bender was developed by NACA personnel to avoid collapsing of the co-axial tubing during bending of the tubes to a desired shape.

Surface Pressure from Rotating Body A scheme similar to that used to obtain temperatures from rotating bod- ies is also used to obtain surface pressure measurements. Pressure lines from a model are fed into a hollow shaft (fig. 34). Each tube is then al- • lowed to vent into a chamber composed of the hollow shaft, bearings, and a stationary housing. All pressure sealing is accomplished by the bearings and felt seals. The pressure from each sealed chamber is then transmitted to a manometer. A water-jacket cooling system (not shown) is provided for high-rotational-speed operation. This pressure system permits simultaneous readings Qf many pressures and is generally limited only by the number of bearings used.

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\ APPENDIX C lCING lNSTRUMINT~ The deteniination of liquid-water content and droplet-aiae diatribution of natural and artificial clouds ha1 received conaiderable attention in con- nection with cloud phyaic1 1tudie1 and, in particular, in aircraft icina 1tudie1. A knowledge of the liquid-water content and droplet-aiae di1tribu- tion in cloud• i1 of fundAMntal importance in evaluating rate and area of ice formation on various aircraft component,, rate and area of ero1ion by impinging droplet, on various aircraft surfaces such as radOM&, reduction of visibility, attenuation of radar, and the basic lllf!Chanism of cloud forma- tion and precipitation.

Numerous methods for determining these parameters have been proposed J and te-·ed, but each method suffers limitations as to accuracy or ease in obtaining or reducing the data to ,,sefol form. In so111e cases the limita- tions become very severe when measurements are attempted in high-speed air- streams. In addition to the rotating multicylinders and pressure-type .

icing-rate meter discussed in the test, some metho~s and techniques that have been widely employed to determine liquid-water content and/or droplet size are: (1) Cloud camera (2) Oil slides (3) Oil-stream aeroscope (4) Heated probes The methods are described and discussed in references 38 to 40.

The use of cameras (fig. 35) to photograph droplets directly in a cloud (ref. 38) is based on fundamental principles and is basically a sound tech- nique, but there are practical difficulties. Because of the high magnifica- tion required, the volume of the field of view is extremely small. As a result, the average number of droplets per 8- by 10-inch picture is small in clouds of moderate liquid-water contents. Therefore, a large number of pic- tures are required in order to obtain a size distribution. Since the mag- nification required is high, it is difficult to design a ca1Bera ao that the object plane is outside the undisturbed airstream about an airplane ~r cam- era mount.

The oiled-slide technique, where a glass slide covered with a suitable oil is exposed to a droplet-laden airstream and is then photographed through a microscope, has been us~d also to determine droplet-size distributions.

This method yields photographs with a large number of droplets per picture from which the droplet sizes may be measured. However, because of the rela- tively large size of the slide compared with th6 eize of droplets, the over- all collection efficiency and the local collection efficiencies of the slide

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vary con1iderably with droplet 1i1e. The droplet-aiae diatribution for any given area of the slide must be corrected according to the local collection !

effici•nciea in order to obtain the true droplet-1i1e di1trihution of the cloud. The local collection efficiencies used for thia correction are baaed ;- upon that of a ribbon in ideal two-dimen1ional flow. The expo,~r• time re- ; t quired in order not to 1aturate the elide with dropleta mu1t be of the order !

of a fraction of a eecord. Thia present• some difficultie1 in that the ' elide muat be moved rapidly or a protective cover mu1t be opened and clo1ed rapidly. Thia motion disturbs the airflow field in the vicinity of the slide, and therefore the collection efficienciea of the slide are not the same as for a ribbon in ideal flow.

An oil-stream aeroscope composed of five main pa!ts (fig. 36) - d~oplet pickup probe, circulating pumps for oil and air, photographic cell, light source, and a photomicrographic camera - has been developed. The droplet pickup probe consists of a small-diameter tube with a small hole on one ,.

side. When operati~, the probe is arrang,ad so that the small hole faces upstream to the air flow carrying the cloud droplets. Oil is forced by a pump through the pickup probe in the direction indicated in the sketch. As the oil passes the small hole, any water droplets that enter are trapped in the oil. Oil does not flow out of the droFlet pickup hole, because the oil pressure is maintained at atmospheric pressur~ by the air pump shown in fig- ure 36. The oil containing the droplets then flows through the transparent plastic cell where the droplets are photographed with a photomicrographic camera. The channel through the plastic cell narrows down at the point where the pictures are tak~n, so that all the droplets are approximately in the object plane of the camera. After leaving the plastic cell, the oil passes through a filter and trap where the water droplets are removed. The droplet size and distribution can then be determined by measuring the images on the photographs from the known magnification. After the droplet distri- bution is known, the liquid-water content of the cluud can be calculated from the known geometery of the instrument, the airspeed, and the oil-flow rate. Limited data indicate that this instrument shows excellent promise for obtaining the desired information.

The heated-wire instrument consists basically of a loop of reRiatance wire (refs. 39 and 40) which is mounted in the airstream (fig. 37) and is heated electrically by passing current through the wire. The wire Jiameter is Q.021 to 0.064 inch, with a maximum power input of 31 to 300 watts, re- ..

spectively (ref. 40). The change in wire resistance from the clear-air con- dition, resulting from cooling due to evaporation of impinging cloud water droplets, is used as a measure of the liquid-water content, or icing sever- ity. Although the heated-wire instrument has several disadvantages a• pointed out in reference 40, a workable instrument can be obtained that is very useful in studying cloud microstructure.

A variation of the heated-wire instrument is currently under develop-

r

ment at the ::ACA Lewis laboratory. This instrument consists of a heated ,....._

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r

tube operating at constant aurface temperature with a variable power input.

t

Thia in,trwnent baa the following advantage, over a constant-power heated• wire probe: (l) The mea,ured change in required power i1 linear with water impinge- ment, becau1e the 1urface temperature it fixed.

(2) The change of heat•tranafer coefficient under all condition• ia minimized.

(3) The 1en1itivity to water impinaement i, maximized.

(4) The powe~ input i, eaaily measured.

(5) With proper deaian, the time constant i• l••• than that of a wire heated with constant power.

While the control circuit for thia probe ha• proved formidable, a 1ati1fac- tory unit has been designed and operated. The probe ia currently being cal- ibrated in the Lewis icing tunnel.

a'\,---··-----·- - - --·

i

UIEUNCIS 1. Kacker, Paul T., and Dorich, Robert G.: A Swaary of Neteoroloaical Condition• A11ociated vith Aircraft lcina and a Propoaed Method of Selectina Deaian Criterion• for lee-Protection lq~i,..nt. NACA TN 2569, 1951.

2. Lewie, Willi•, and lerarun, Noraan R.: A Probability An•ly•i• of the Meteoroloaical Factor• Conducive to Aircraft lcina in the United Stat••• NACA TN 2738, l9S2.

3. Jon••• Alun R., and Levi,, William: lecoaaended Value• of Meteorological Factor• to be Conaidered in the De1ian of Aircraft lee-Prevention Equipment. NACA TN 1855, 1949• 4. Lewia, William, Perkin,, Porter J., and Brun, Rinaldo J.: Procedure • for Measuring Liquid-Water Conte~t and Droplet Siaea in Super- cooled Cloud1 by Rotatina Multicylinder Method. NACA RN E53D23, 1953.

5. Perkin•, Porter J., Mc<ullough, Stuart, and Lewia, Ralph D.: A Simpli!i.ed In1tru,: ant for Recordina and Indicating Frequency and Intensity of Icir,~ .• Conditions Encountered in Plight. NACA llM ES1El6, 195 l.

6. Bru~, Rin~ldo J., Gallagher, Helen M., and Vogt, Dorothea E.: lmpingement of Water Droplet, on NACA 65A004 Airfoil and Effect of Change in Airfoil Thickne11 from 12 to 4 Percent at 4° Angle of Attack. NACA TN 3047, 1953.

7. Brun, Rinaldo J., Gallagher, Helen H., and Vogt, Dorot.hea !.: Impingement of Water Droplets on NACA 651·208 and 651-212 Air- foils at 4o Angle of Attack. NACA TN 2952, 1953.

a. Guibert, A.G., Jan1aen, E., and Robbins, w. H.: Delenaination of

Kate, Area, and Distribution of Impingement of Waterdrop1 on Var- ious Airfoils from Trajectories Obtained on the Differential Ana- lyzer. NACA llM 9A05, 1949.

9. Brun, Rinaldo J., Gallacher, Helen M., and Vogt, Dorothea!.: Impingement of Water Droplets on NACA 65A004 Airfoil at 8° Angle of Attack. NACA TN 3155, 1954.

10. Brun, Rinaldo J., Serafini, Johns., and Gallagher, Helen M.: Impingement of Cloud Droplets on Aerodynamic Bodie• aa Affected by Compressibility of Air Flow Around the Body. NA.CA TN 2903, 1953.

11. Dorsch, Robert G., and Brun, Rinaldo J.: A Method for Detenining Cloud•mDroplet l11pingement on Swept Wings. NA.CA TN 2931, 1953.

.. ..., J

12. lrun, tinaldo J., and Dorach, lobert G. 1 lapina--•t of Water Droplet • on aa lllipaoid with finaae•• latio 10 in Axia,-tric flow. IUCA n 3147, 1954.

13. Doracb, lobert G., lrun, Rinaldo J., and Greu, John L.: lapiq-nt of Water Droplet, on an lllip1otd with Pinen••• Ratio Sin Axiay• metric Plow. BACA TN 3099, 1954.

14. lrun, Rinaldo J., and Meraler, Harry w.: lapinc .. at of Water Droplet •

on a Cylinder in an lncoapre11ible Plow Field and lvaluatioa of lotatiq Nulticylinder Method for Meaaureaeat of Droplet-Ii•• Di •- trlbution, Voluae-Nediaa Droplet Size, end Liquid-Water Content in Cloud1. NACA TN 2904, 1953 • •

U. von Glahn, Uva H., Geld111r, Thoaaa r., and Say•ra, Willi• H., Jr.: A

Dye-Tracer Technique for lxperi•ntally Obtainina lapinaeMnt Characteri1tic1 of Arbitrary Bodi•• and a Method for Deterainina Droplet Siae Di1tribu:ion. NACA TN 3338, 1955.

16. Sbenun, P., Klein, J. s., and Tribu1, M.: D•tenination of Drop Trajectori•• by Mean, of an lxten•i~n of Stok11' Lav. Eng. a.,.

lnat., Univ. Mich., Apr. l9S2. (Air aea. and Dev. co ... nd, USAF, Contract AP 18(600)-Sl, Proj. 11992-D.)

17. von Glahn, Uve 8., and Gray, Vernon H.: Effect of lee Porwationa on Section Draa of Swept NACA 63A-009 Airfoil with Par- tial•ipan Leading-Ed&• Slat for Variou1 Hode1 of Thermal lee Pro- tection. NACA llM ESJJ30, 1954.

18. Gray, Vernon H., and von Glahn, Uwe E.: Effect of lee and Pro1t Formation• on Drag of NACA 651•212 Airfoil for Variou1 Hodea of Therwal lee Protection. NA.CA TN 2962, 1953.

19. Levia, Ja•• P., and Blade, !lobert J.: lxperi•ntal lnve1ti1ation of ladome Icing and Icing Protection. NACA TM IS2J31, 1953.

20. Neel, Carr B., Jr., Berarun, Norun R., Jukoff, David, and Schlaff, Bernard A.: The Calculation of the Heat Required for Wina Therul lee Prevention in Specified Icing Condition•• NACA TN 1472, 1947.

21. GelJer, Thomae r., and Levi1, Ja•• P.: Coapari1on of Heat Tran1fer from Airfoil in Natural and Simulated Icing Condition,. NACA TN 2480, 19Sl.

22. von Glahn, u.: P:·P.l .•inary le1ult1 of Heat Trander fr• a Stationary and Rotating lllip1oidal Spinner. NACA KM ESlF02, 19SJ.

23. Gelder, Thou•,., Levi,, Ja•• ,., and Kouts, Stanley L.: Icing Protection for a Turbojet Tran1port Airplane: Heatina lequire- aMtnta, Method • of Protection, and Perfonunce Penaltiaa. NMiA TN 2066, 1953.

2J ,

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24. llardy, J. It.: IC.in.tic T-,.rature of Wet Surfac.~• - A Metbod of C.lculatina the Allount of Alcohol Required to Prneat lee, and th• l Derivati~" of the P1ychromatric lquation. NACA WR A-8, 1945.

( SuperHdH NACA ARR 5G13.)

l

25. llardy, J. l.: An Analy1i1 of th• Di11ipation of Haat in Condition• of tcina froa a Section of th• Vina of the C-46 Airplana. MCA lap.

831, 1945. (Super1ada1 NACA ARI 4111a.)

26~ Gray, v. H., lowdan, D. T., and von Glahn, u.: Praliainary le1ult1 of

Cyclical De-Icing of a Gaa-Haatad Airfoil. NACA RM 15U29, 1952.

27. Gray, Vernon H., and Bowden, Dean T.: Coaapat'i1on of Several Method• of Cylical De-Icing of a Ga1•Heated Airfoil. ~A RM E53C27, 1953.

28. Lewi1 J.,., P., and Bowden, Dean T.: Preliminary lnva1tiaation of

Cyclic De-Icing of an Airfoil U1ing an External Electric Heater.

NACA RM E5U30, 1952.

29. Cole1 Willard D., and Ruggeri, Robert S.: Experimental Inveatigation of Sublimation of lee at Sub1onic and Superaonic Speed, and It1 Relation to lwat Transfer. NACA TN 3104, 1954.

30. Colet, Willard, Rollin, Vern G., and Mulholland, Donald R.: lcina-Protection Requir&11ent1 for leciprocatina-Engine Induction Sy1tem1. NACA Rep. 982, 1950. (Super1edea NACA TN 1993.)

31. Acker, Loren W.: Natural Icina of an Axial-Flow Turbojet Enaine in Flight for a Single Icing Condition. NACA RM E8F0la, 1948.

32. Acker, Loren W.: Preliminary lleault• of Natural Icing of an Axial-Flow Turbojet Engine. NACA RM E8Cl8, 1948.

33. Gra1, Vernon H., and Bowden, Dean T.: lcing Characteri1tic1 and Anti-Icing Heat Requirement• for Hollow and Internally Modified Gas-Heated Inlet Guide Vanes. NACA RM E50108, 1950.

34. Callaahan, Edmund E., and Serafini, John S.: A Method for Rapid Determination of the Icing Limit of a Body in Terar.J of the Stream Conditions. NACA TN 2914, 1953.

35. Callaahan, Edmund F.., and Serafini, John S.: Analytical lnveatiaation of Icing Limit for Diamond-Shaped Airfoil in Transonic and Super· sonic Flow. NACA TN 2861, 1953.

36. Coles, Willard D.: lcina Limit and Wet-Surface Temperature Variation for Tvo Airfoil Shapes under Simulated Kigb•Speed Flight Condi• tiona. NACA TN 3396, 1955.

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37. Laapuir lning and Bloclgett latberiu B.: A Nath ... tical 1 1 1

f

lnve1tiaation of Weter Droplet Trajectori••• Tech. Rep. No. 5418, Air Materiel C0111and I.AF, reb. 19, 1946. (Contract No. W-33-038- ac-9151 vi-th General llectric Co.)

38. McCullough, Stuart, and Perkin1 Porter J.: Plight Camera for Photographing Cloud Droplet, in Natural Su1penaion in the Atao- apbere. BACA Ill BSUI.Ola, 1951.

39. Neel Carr a. Jr. and Steinaeta Char lea P.: The Calculated and

1 1 1 1 Measured Perforaance Characteristics of a Heated-Wire Liquid- Water-Content Meter for Measuring Icing Severity. NACl TN 2615 1952.

40.:, "Neel, Carr a.: A Heated-Wire Liquid-Water Content ln1trument and Results of Initial Flight Teat in Icing Condition•~ _BACA RM ..

A54123, 19~5 • ,,.

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LOCAL IMPINGEMEN T RA -E ON A 15-PERCENT THICK

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TYPICAL AIRFOIL ICE FORMATIONS

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Fi e 20 .

PNEUMATIC BOOT DE-ICING SYSTEM Fi 21 ICING PROTECTION FOR PISTON ENGINE-INDUCTION SYSTEM SPEE D. DENSITY Hfl'EANi, Oll.-HEA TE> ntlOTTI.O AH, THROTTU IOOY I L PAGE IS , ... I' LI TY

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NACA 3.84x 1O-INCH HIGH-SPEED ICING DUCT TUNNEL

REFRIGERATED AIR SUPPLY l

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NACA 12 x 12 -INCH HIGH-SPEED ICING DUCT TUNNEL

ALTITUDE EXHAUST SPRAY

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SCHEMA TIC DIAGRAM FOR PRESSURE MEASURING SYSTEM

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F igure 37

4 4

l

l SELECTED BIBLIOGRAPHY OF

l

i NACA-NASA AIRCRAFT ICING PUBLICATIONS Meteorology of Icing Clo'!!l!, l. Berarun, N.R. and Lewie, Wm.: A Probability Analyaia of the Nal-73269 Meteorological Factor• Conducive to Aircraft Icing in the United States. NACA TN 2738, 1952.

l

l 2. Hacker, P.T. and Douch, R.G.: A S\llllll&ry of Meteorological N&l-73270 Conditions Associated with Aircraft Icing and a Proposed Method of Selecting Design Criterion& for Ice Protection Equipment.

NACA TN 2569, 1951.

3. Jones, A.R. and Lewis, liln.: Recomended Values of Meteorological • N81-7li71 Factors to be Considered in the Design of Aircraft Ice Prevention Equipment. NACA TN 1855, 1949.

4. Kline, D.B.: Investigation of Meteorological Conditions Associated NSl-73272 with Aircraft Icing in Layer-Type Clouds for 1947•48 Winter.

NACA TN 1793, 1949.

5. Kline, D.B. and Walker, J.A.: Meteorological Analysis of Icing NSl-73273 Conditions Encountered in Low-Altitude Stratiform Clouds.

NACA TN 2306, 1951.

6. Lewis, Wm.: Icing Properties of Non-Cyclonic Winter Stratus Clouds.

N81-73274 NACA TN 1391, 1947.

7. Lewis, liln. ~nd Hoecker, W.H., Jr.: Observations of Icing Con¥tions NSl-73275 Encountered in Flight During 1948. NACA TN 1904, 1949.

8. Lewis, Wm., Kline, W.B. and Steinmetz, C.P.: A Further Investigation NSl-73276 of the Meteorological Co~ditions Conducive to Aircraft Icing.

NACA TN 1424, 1947.

9. Perkins, P.J.: Preliminary Survey of Icing Conditions Measured NSl-73277 During Routine Transcontinental Airline Operation. NACA RM E52J06, 1952.

10. Perkins, P.J.: Statistical Survey of Icing Data Measured on NSl-73278 Sch~duled Airline Flights over the United States and Canada.

NACA RM £55F28a, 1955.

11. Perkin,, P.J.: Icing Frequencies Experienced Durin& Climb and Deacent NSl-73279 by Fighter-Interceptor Aircraft. NACA TN 4314, 1958.

. .,,.:..,__ . .._..

ct •• -· •- - tod

4 , SW • ~,- -~ ....... L"•• • ----~.

··-, -~.__ 12. Perkin1, P.J. and Kline, D.B.: Analy1i1 of Mateoroloaical Data N&l-73280 Obtained During Flight in a Supercooled Stratiform Cloud of High Liquid Water Content. NACA RM 151D18, 1951.

13.

Perkin1 1 P.J., Lewi,, V. and Mulholland, D.R.: Sutiatical Study of N81-73281 Aircraft Icing Probabilitie1 at the 700• and 500-Millibar Level, over Ocean Areas in the Northern Hemisphere. MCA tN 3984, 1957.

14. Perkin1 P.J.: SU11111&ry of Stati1tical Icing Cloud Data Meaaured over N81-73282 United States and North Atlantic, Pacific, and Arctic Ocean, During Routine Aircraft Operations. KASA Memo 1·19·59E, 1959.

Fundamental Properties of Water 15. Levine, J.: Statistical Explanation of Spontaneous Freezing of Water N81-7328J Droplets. NACA TN 2234 1 1950.

• 16. Dorsch, R.G., and Hacker, P.t.: Photomicrographic Investigation of Spontaneous Freezing Temperatures of Supercooled Water Droplets.

NSl-73284 NACA TN 2142, 1950.

Hacker, P.T.: Experimental Values of the Surface Tension of 17.

NSl-73285 Supercooled Water. NACA TN 2510, 1951.

18. Dorsch, R.G., and Boyd, B.: X•Ray Diffraction Study of the Internal NSl-73065 Structure of Supercooled Water. NACA TN 2532, 1951.

19. Dorsch, R.G., and Levine, J.: A Photographic Study of Freezing of NSl-73286 Water Dtoplets Falling Freely in Air. NACA RM E51Ll7, 1952.

20. Lowell, H.H.: Maximum Evaporation Rates of Water Droplets Approaching N81-73287 Obstacles in the Atmosphere. NACA TN 3024, 1953.

21. Hardy, J.K.: Kinetic Temperature of Wet Surfaces. A Method of N81-73321 Calculating the Amount of Alcohol Required to Prevent Ice, and the Derivation of the Psychometric Equation. ARC B6iM 2830~ 1953.

NACA ARR 5Gl3, 1945. See also WR A-8.

Meteorological Instruments 22. Neel, C.B., Jr, and Steinmetz, C.P.: The Calculated and Measured

I

NSl-73149 Performance Characteristics of a Heated-Wire Liquid-Water-Content J Meter for Measuring Icing Severity. NACA TN 2615, 1952.

j

'

23. Lewis, Wm., Perkins, P.J., and Brun, R.J.: Procedure for Measuring l NSl-73322 Liquid-Water Content and Droplet Sizes in Supercooled Clouds by Rotating Multicylinder Method. NACA RM E53D23, 1953.

J

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,._ ...... --...,. __ ,.. ____ _

tre»ercen-r •

- '··-

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24. McCullough, s., and Perkin,, P.J.: PU&ht Camera for •botoaraphina

NSl-73288 Clnud Droplet• in Natural Su1pen1ion in the Atmoaphere.

NACA RM ESOlCOla, 1951-.

25. Perkin1, P.J.: Plight ln1trum•nt for Meaauraent of Llquld•Water NBl-73150 Content in Cloud• at Temperatures Above and Below Freeaina.

NACA RM ESOJ12a, 1951.

26. Perkin1 1 P.J., McCullough, S. and Lewi1, l.D.: A Simplified NBl-731S1 In1trument for Recording and Indicating Frequency and lnten1ity of Icing Conditions Encountered in Flight. NACA RM ESlE16, 1951.

~.

27. Brun, R.J., Levine, J., and Kleinknecht, K.S.: An ln1trument • N81-731S2 Employing Coronal Discharge for Determination of Droplet Size Distribution of Clouds. NACA TN 2458, 1951.

J

• 28. Levine, J., and Kleinknecht, K.S.: Adaptation of a Cascade Impactor

N81-731S3 to Flight Measurement of Droplet Size in Clouds. NACA RM E51G05, 1951.

29. Howell, W.E.: Comparison of Three Multicylinder Icing Meters and N81-73154 Critique of Multicylinder Method. NACA TN 2708, 1952.

30. Jones, A.R. • and Lewis, w.: A Review of Instruments Developed for I NSl-7315S the Measurement of the Meteorological Factors Conducive to Aircraft I Icing, NACA RM A9C09, 1949.

I 31. Neel, C.B.: A Heated-Wire Liquid-Water-Content Instrument and NSl-73156 Results of Initial Flight Test in Icing Conditions.

I

f

NACA RM A54123, 1955, 32. Hacker, P,T.: An Oil-Stream Photomicrographic Aeroscope for NSl-73157 Obtaining Cloud Liquid-Water Content and Droplet Size Distributions in Flight. NACA TN 3592, 1956.

Impingement of Cloud Droplets

l

33. Bergrun, N.R.: An Empirical Method Permitting Rapid Detennination of NSl-73099 the Area, Rate, and Distribution of Water-Drop Impingement on an Airfoil of Arbitrary Section at Subsonic Speeds.

NACA TN 2476 1951.

34. Bergrun, N.R.: A Method for Numerically Calculating the Area and NSl-73100 Distribution of Water Impingement on the Leading Edge af an Airfoil in a Cloud. NACA TN 1397, 1947.

35. Brun, R.J., Serafini, J.S., and Ho1ho1, G.J.: Impingement of Water N81-73101 Droplets on an NACA 651-212 Airfoil at an Angle of Attack of 4°.

NACA RM E52B12, 1952.

• 41 ~ • _,.)f,' 36. Hacker, P.T., Brun, ll.J., and loyd, 1.: lllpinament of Dropleta in N81-73102 90° llbow1 with Potential Flow, MCA TN 29tS, 1953.

37. Serafini, J.S.: Illpiqaeat of water Dropleu on Wecfae• and Diamond 181-73103 Airfoil• at Sup•~•onic Speedl. MCA lap. 1159, 19'4.

(Super1ede1 BACA TN 2971).

38. lrun, J..J., Call4her, H.K., and Vost, D.I.: lapiqement of W.ter NBl-73104 Droplet, on Ntr\ 65A•004 Airfoil ana Effect of Chan&• in Airfoil 1'hickne11 from 12 to 4 lerc~~t at 4 Anal• of Attack.

NACA TN 3047, 19SJ.

39. Brun, ll.J., Callqhfilr, H.K., and Vogt, D.E.: lmpit'lement of Water N81-73105 Droplet, on NACA 6S1•208 and 651•212 Airfoil• at 4° An&l• of Attack.

NACA TN 29S2, l~S3.

40. Brun, J..J., and Mergler, K.W.: Iapiqement of Water Droplet• on NSl-73106 a Cylinder in an lncomprr11ible Flow Field and Evaluation of Rotating Multicylinder Method for Mea1urement of Droplet-Size Di•tribution, Volume Median Droplet Size, and Liquid-Water Content in Clouds.

~CA TN 2904, 1953.

4l. Brun, l,J,, Serafini, J.S., and Gallagher, H.M.: Impingement of Cloud NSl-73107 Droplet• on Aerodynamic Bodies as Affected by Compre11ibility of Air Flow Around the Body, NACA TN 2903, 1953.

42. Guibert, A.G •• Jan11en E., and Robbins, W,M.: o-ttennination of late, NSl-73108 Area, and Di•tribution of Impingement of Waterdrcp1 on Varioua Airfoil• from Trajectoriea,Obtained on the Differential Analyzer.

NACA RM 9A05, 1949.

43. Douch, R.G., and Brun, ll.J.: A Method for Determining Cl~ud•Droplet N81-73109 Impingement on Swept Wings, NACA TN 2931, 1953.

44. Brun, R.J., •nd Dorsch, ll.G.: Impingement of Water Dropleu on an NSl-73110 Ellip•oid wilh Fineneaa ll&tio 10 in Axi•ymnetric Flow.

NACA TN 3147, l~S4.

45. Dorich, R.G., Jrun, a.J., and Gregg, J.L.: Impingement of Water NSl-73111 Droplet• on an Ellipsoid with Finen••• ll&tio 5 in A.xiayanetric Flow.

NACA TN 3099, 1954.

46. Dor•ch, R.G., and Brun, a.J.: Variation of Local Liquid•Water NSl-73112 Concentration about an Ellip•oid of Finene11 Ratio 5 Moving in a Droplet Field, MCA TN 3153, 19S4.

47. Brun, Jl,J., Calla1her, 11.M., and Vogl• D.I.: lllpina ... nt of Water NBl-73113 Dropleta on NACA 6SA004 Airfoil at 8 Angle of Attack.

MCA TN 31S5, 1954.

I ' I i I ; ' ' ..

-I

----~-~-F-<"-~-~• ·~----------------~-___,_...__~---

.•. '"" ."'.; 41.

Jrun, R.J., and Dorich, R.G.~ Variation of Local Liquid•Vater 1'81-73114 Concentration about an Ellip1oid of Finene11 Ratio 10 Movina in a Droplet Fiald. MCA TN 3410, 1955.

49.

von Glahn, U., Gelder, r.r., and Smyer,, W.H.: A O,e•Tracer

181-73115 Technique for ExperiMntally Obtainina lllpina ... nt Characteri1tic1 of Arbitrary Bodi•• and a Method for Deteminina Droplet Siae Di1tribution. MCA TN 3338, 1955.

50. Dortch, R.G., Saper, P.G., and Kadow, C.P.: lllpina•ent of Water N81-73116 Droplet• on a Sphere. NACA TN 3587, 1955.

• 51.

Lewi.a, Wm., and Brun, R.J.: lmpina••nt of Water Dropleu on NSl-73117 a Rectanaular Half Body in a 'two•Dimenaional lncompreaaible Flow Field. NACA TN !658, 1956 • • 52.

Brun, R.J., and Vogt, D.E.: Impingement of Water Droplets on NSl-73118 NACA 65A004 Airfoil at 0° Angle of Attack, NACA TN 3586, l9SS.

53.

Brun, R.J., Lewis, In., Perkins, P.J., and Serafini, J.S.: lmpinaement of Cloud Droplets on a Cylinder and Procedure for N81-73119 Measuring Liquid-Water Content and Droplet Size, in Supercooled Clouda by Rotating Multicylinder Met~d. NACA Rep. 1215, 1955.

(Super•e~es NACA TN'a 2903, 2904, and NACA RM E53D23) 54. Brun, R.J.: Cloud-Droplet Ingestion in Engine Inlet• with Inlet NSl-73120 Velocity Ratios of 1.0 and 0.7. NACA Report 1317 (1uper1ede1 NACA TN 3593), 1956.

55. Gelder, T.F.: Droplet Impingement and Ingestion by Supersonic NSl-73121 Nose Inlet in Subsonic tunnel Conditiona.

NACA tN 4268, 1958.

56. Gelder. T .F., Smyers, W.H. and von Glahn, U.H.: Experimental NSl-73122 Droplet lmpingen,ent on Several Two•Dimenlional Airfoih with Thickness Ratios of~ to 16 Percent. NACA TN 3839, 1956.

57. Hacker, P.T., Seper, P.G. and Kadow, C.F.: Impingement of Droplet• N81-73123 in 60° Elbows with Potential Flow. MCA TN 3770, 1956.

58. Lewia, J.P. and Ruggeri, a.s.: Experimental Droplet Impingement

NSl-73124 on Four Bodiea of Re,•olution. NACA TN 4092, 1957.

59. Brun, R.J. and Vogt, D.: Impingement of Cloud Droplet• on N81-7312S 36.5-Percent·Thick Joukowski Airfoil at Zero Angle of Attack and Oiscu1sion of Uae as Cloud Ke•auring ln1trumcnt in Dye Tracer technique. NACA TN 4035, 1957.

~~-._..,._,---.w-•w-• ,....._w _______ ~-- ---------- 60. von Glahn, u. K.: Uae of truncated flapped Alrfolla for lllplnaeaent N81-7l126 and lclna THtl of rull•Scal• Leadt:ta•lda• l•ctlou.

MCA RM 156£11, 1956.

tropell•t Jclna rros•ss\on

61. Selna, J. and Dar1ow, J.P.: A ruaht lnvHtlaation of the Thermal RSl-73038 Performance of an Alr•Heated Propeller. MCA TN 1178, 1947.

62. l.ewi1, J.P., and Steven,, K.C., Jr.: lclna and De•lclna of NBl-73039 a Propeller'with Internal Electric Blade Keatera.

MCA TN 1691, 1948.

63. l.evi1, J.P.: De•Iclna lffectiven••• of External Electric Heater • N81-73040 for Propeller lladea. NACA TN 1520, 1948.

64. Perkin,, P.J., and Millenaon, K.I.: An Electric Thr~•t Meter Suitable NBl-73158 for Flight lnveatlgatlon of Propeller •• NACA RM E9Cl7, 1949.

65. Mulholland, D.R., and Perkin,, P.J.: lnveatigation of N81-7~041 Effectivene11 of Air•Heatina a Hollow Steel Propellei for Protection Againat lcing 1 • Unpartitioned lladea. NACA TN 1560, 1948.

Et. Perkins. P.J., and Mulholland, D.R.: Inveatiaation of Effectivene11 NBl-73042 of Air-Heating a Hollow Steel Propeller for Protection A&ainat Icing 11 • SO-Percent Partitioned lladea. MCA TN 1587, 1943.

67. Mulholland, D.R., •nd Perkin,, P.J.: Inveati&ation of Effectivene11 NBl-73043 of Air-Heating• Hollow Steel Propeller for Protection A&ainat lc:ing 111 • 25-Percerit Partitioned lladea. MCA TN 1S88, 1948.

68. Gray, V.H., and Campbell, R.C.: A Method for Eatimatina Heat NBl-73044 Require111enu for lee Prevention on Gas-•teated Hollow Propdler Bla~ea. NACA TN 1494, 1947.

69. Neel, C.B., Jr.: An lnveatiaation Utili&ina an Electrical Analosue N81-73045 of Cyclic De-Icing of• Hollow Steel Propeller with an External Blade Shoe. NACA TN 2852, 1952.

70. Neel, C.B •• Jr. An lnveatigation Utilizing an Electrical Analo1ue N81-73046 of Cyclic De•lcing of Holl~w Steel Propellers with Internal Electric Heat~r•. NACA TN 3025, 19.SJ.

71. Bri&ht, L.C., and Neel, c.a •• Jr.: The lffect of the lee Pormation•

N81-73047 on Propeller Performance. MCA TN 2212, 1950.

,

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Jofusr&eo •x•s• Jclng r,es•ss&eo

72. Col••• W.D.: lnv••t'-l•tlon of lclna Characterl1tlc1 of a Typical 181-73048 Liaht•Airplane Enaine Induction Sy1tn. MCA D 1790. 1949.

73. Col••• W.D., llollin, v.c •• and Mulholland, D.a.: lclna ,rotection

181-73049 lequireMnt1 for aeciprocatin&•lnaln• Induction SJ•t••• MCI, ra 982, ltSO.

74. Levi1, J.P.: lnve1tlaatlon of Aerodynmic and lcina Characterlatic1 181-73003 of a Flu1h Alternate•lnlet lnduction•S11tem Air Scoop.

MCA I\H £53£07, 19Sl.

turbine-type Engine and Inlet Icing Stydi11

75. Acker, L.W.: Natural Icing of an Axial•Flow Turbojet lnaine in Plight 181-73050 for a Single Icing Condition. NACA I\H E8F01a, 1948.

76. Acker, L.W.: Preliminary Re1ult1 of Natural Icing of an Axial-Flow 1'81-73051 Turbojet Engine. NACA RM E8Cl8, 1948.

77. Gray, V.K., and Bowden, D.t.: Icing Characteriltic1 andAnti•J.cing Nll-73052 Keat Requirement• for Hollow and Internally Modified Gas-Heated Inlet Guide Vane,. NACA RM E50I08, 1950.

78. Lewis, J.P. and Ruaaeri, R.S.: An Inveati&ation of Heat Transfer NBl-73127 from a Stationary and Rotatina Ellipsoidal Forebody of Fineness Ratio J. NACA TN 3837, 1956.

79. Ruaaeri, R.S. and Lewis, J.P.: Investigation of Heat Transfer NSl-73128 from a Stationary and Rotating Conical Forebody. NACA TN 4093, 19S7.

80. von Glahn, U.K., and llatz, a.£.: Inve1ti&ation of Power Nll-73129 Re-Requirements for lee Prevention and Cyclical De•Icin& of Inlet Guide Vanes with Internal Electric Heater,. NACA I\H E50K29, 1950.

81. ~on Glahn, U.K., Callaahan, E.E. and Gray, V.K.: NACA lnve1tigation1 NBl-73053 of Icing-Protection Systems for Turbojet•Engine Installation.

NACA RM I51Bl2, 1951.

82. Gelder, T.F.: Total Pre11ure Distortion and lecovery of Supersonic NSl-73004 )?011 Inlet with Conical Centerbody in Subsonic Icing Conditions. NACA 1M E57G09, 1957.

83. von Clahn, U., and Blatz, I.E.: lnve1ti1ation of Aerodynamic and N81-730S4 Icing Characteristic• of Water-Inertia-Separation Inlets for Turbojet•Engine lee Protection. NACA I\H ESOE03, 19SO.

Wing Icing Protection 84 Hardy, J.K.: An Analy1i1 of the Di11ipation of Keat ia Conditions of lffll-73130 Icing from a hction .,.f the Wing of the C-46 Airplane, NACA TR 831, 19~5.

I.

I '

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~

' 15.

ler1run, N.I., and Med, c.a.: Tbe C&lculatiota of tbe leat a.quired

~ l l 181-73131 f~r Vina Tharaal le• Prevention in Specified lcina Condition,.

r MCA flC 1472, 1947.

t I i 16.

Gray, V.H., lovden, D.T., and von Glahn, U.: PreUatnary le1ult1 of 181-73132 C,cUcal De•ldn& of a Ga1•llu:ed Airfoil. MCA 1K IS1J2t 19S2.

t

17. Levt.1, J. 1. , and lovden, D. T. : PreUainary lnw1 tiaatlon of C,cUc 181-73133 De•lciq of an Airfoil U1ina an lxcernal llectric Heater.

NACA 1M ISlJlO, 19S2.

f 18. Gelder, T.F., and Levi1, J.P.: Compari1on of Heat tran1fer from

181-73134 Airfoil in Natural and Silllulated lcina Condition,.

•

r

NAC4 '1'N 2480, 1951.

Callqhan, E.E., and Serafini, J.S.: A Netbod for Rapid Deter11ination 89.

Rll-73135 of the lcina Limit of• lody in Term• of the Strea Conditions.

NACA '1'N 2914, 1953.

90. Callqhan, E.E., and Serafini, J.I.: Analytical lnve1ti1acion of lcina Limit for Diamond-Shaped Airfoil in 'tran1onic and Supersonic Rll-73005 Flow. NACA TN 2861, 1953.

Ruaa•ri, R.S.: Denlcina and Ruaback Characteri1tic1 of Three Cyclic 91.

Electric, External De-Icing loot, Employina Chorcwi1e Sheddina.

RBl-73006 NACA RM ES3C26, 1953.

92.

Gray, V.H., and Bowden, D.T.: Compari•~n of Several Methoda of Cyclic J>e•lcina of a Ga1•Kuted Airfoil. MCA au E53C27, 1953.

1181-73023 93. N••l, C.I., Jr.: The De1i1n of Air-Heated Thermal lce•PreventiQn Sy1te111. (Pre1ented at th• Airplane lcina lnfonution Courie ~t th• 1181-73024 Univer1ity of Michi&an, Karch 30 - April 3, 1953). MCA Tl•llJO, 1954.

loVl'Jtn, D. T.: lnvHti&ation of forou1 Ga1•Heated Leadir.a•Ed&e Section 94.

NSl-73025 for lcing Protection o! a Delta Wine. NACA 1M £54103, 19S5.

95. Gray, V.H., and von Glahn, U.K Heat lequir ... nt1 for lee Protection 6: of a Cyclically Ga1•Heated, 36 Swept Airfoil with fartial•Span N&l--73136 Leadin&•Edae Slat. NACA L~ t56B23, 19S6.

Gowan, W.H. and Mulholland, D.R.: !ffectivene11 of Thermal•Pn•umatic 96.

NSl-73026 Airfoil•lce•Protection Sy1tem. MCA 1H UOKlOa, 19Sl.

S2 1-

--

• - A, •• -

t AUH!fj»fJ •·•~~•-~-•. :', ":¥! "''--:~?<- -~--------~ . -·.....,•-----...,,....~ Performance Penalties 97. von Glahn, U.H., and Gray, V.H.: Effect of Ice Formation• on Section NSl-73007 Drag of Swept NACA 63A-009 Airfoil with Partial-Span Leading-Edge Slat for Various Nodes of thermal lee Protection.

NACA RM E53J30, 1954.

Gray, V.H., and von Glahn, U.H.: Effect of Ice and Frost Formations 98.

on Drag of NACA 65 Airfoil for Various Modes of thermal Ice NBl-73008 1-212 Protection. NACA TN 2962, 1953.

99. Preston, G.M., and Blackman, C.C.: Effects of lee Formations on NBl-73027 Airplane Performance in Level Cruising Flight. NACA TN 1598, 1948.

100. Gelder, t.F., Lewis, J.P., and Koutz, S.L.: Icing Protection for NBl-73028 a Turbojet Transport Airplane: Heating Requirements, Methods of Protection, and Performance Penalties. NACA TN 2866, 1953.

101. Bowden, D.T.: Effect of Pneumatic De-leers and lee Formations on NBl-73009 Aerodynamic Ch:'racteristics of an Airfoil. NACA TN 3564, 1956.

102. Gray, V.H.: Correlations Among lee Measurements, Impingement Rates, N81-730l0 Icing Conditions and Drag of a 65A004 Airfoil. NACA TN 4151, 1958.

103. Gray, V.H. and von Glahn, U.H.: Aerodynamic Effects Caused by Icing NSl-73011 of an Unswept NACA 65A-004 Airfoil. NACA TN 4155, 1958.

104. Gray, V.H.: Prediction of Aerodynamic Penalties Caused by lee NSl-73012 Formations on Various Airfoils. NASA TN D-2166, 1964.

Windshield Icing Protection 105. Holdaway, G.H., Steinmetz, C.P., and Jones, A.R.: A Method for NSl-73137 Calculating the Heat Required for Windshield Thermal lee Prevention Based on Extensive Flight Test in Natural Icing Conditions.

NACA TN 1434, 1947.

106. Ruggeri, R.S.: Preliminary Data on Rain Defl~ction from Aircraft NSl-73138 Windshields by Means of High··Velocity Jet-Air Blast.

NACA RM E55El7a, 1955.

Cooling Fan Icing Protection 107. Lewis, J.P.: Wind-Tunnel Investigation of Icing of an Engine NSl-73055 Cooling-Fan Installation. NACA TN 1246, 1947.

zsou:;

'--~ .. -~-- ~ ~--. -- . ------

lade Icing Prot•'11!m

108. I.evil, J.P.: An Analytical Study of Heat lequlreMnta for lctna 181-73139 Protection of ladomes. MCA RM 15lA22, 1953.

i 109. Levis, J.P.• and Blade, R.J.i lxperf.Mntal lnvHti&atlon of kadome

•

' ; 181-73029 lcina and Icing ,rotection. MCA IN 152Jl1, 1953.

Antenna lcina 110. Kepple, W,L,: Determination of Aircraft Antenna Loada Produced by N&l-73166 Natural Icing Condition,. NACA RM 17H26•, 1948.

111, Gowan, W.H., Jr.: Vibration and l~ing lnveatigation of CM Type V-109 N&l-73167 Very-High-Frequency Aircraft Antenna. NACA 1M S19D20, 1949.

Inlet and Vent Icing Protection

112. Ruaaeri, l,S., von Glahn, u., and Rollin, v.c.: lnveatigation of

N&l-73013 Aerodynamic and Icing Characteri1tic1 of Recessed Fuel-Vent Configurations. NACA TN 1789 1949.

Jet Penetration 113. Callaghan, E.E., and Ruggeri, R.S.: lnveatigation of the Penetration N8l-73140 of an Air Jet Directed Perpendicularly to an Airatream.

NACA TN 1615, 1948.

114. Ruggeri, R,S,, Callaghan, E.E., and Bowden, D.T,: Penetration of NBl-73141 Air Jet1 l11uing from Circular. Square, and Elliptical Orifices Directed Pe~pendicularly to an Airatream. NACA TN 2019, 1950.

115. Callaghan, E.E., and Bowden, D.T.: Investigation of Flow Coefficients NSl-73142 of Circular, Square, and Elliptical Orifices at High Pressure Ratios.

NACA TN 1947, 1949.

116. Ruggeri, R.S.: General Correlation of Temperature Profiles Downstream NSl-73143 of a Heated Air Jet Directed at Various Anglea to Airstream.

NACA TN 2855, 19~2.

117. Callaghan, E.E., and Ruggeri, R.S.: A General Correlation of NBl-73144 Temperature Profiles Downstream of a Heated Air Jet Directed Perpendicularly to an Airatream. NACA TN 2466, 1951, Beat Transfer 118. Gray, V.H.: lnlprovementa in Heat Transfer for Anti•lclng of NSl-73030 Gaa•Heated Airfoilr vith Internal Fins and Partitions.

NACA TN 2126, 1950.

119. Gray, V.H.: Simple Graphical Solution of Heat tranafer and Evaporation N81-73145 fro~ Surface Heated to Prevent Icing, NACA TN 2799, 1952.

120, Callaghan, E.E.: Analogy between Mall and heat Transfer vith Turbulent NSl-73146 flow. NACA TN 3045, 1953.

-.--- ,......_ --··· ... ___,,._._~--~;~..--.~""l"'I'.,,_,.,,...~~-.._,,....,,.,,.. .. _ -· .. , 121. Col••• W.D., and Ruaaeri, R.S.: Experimental lnve1tiaation of Nll-73147 Sublimation of lee at Sub1onic and Super1onic Speed• and it • lelation to Keat Tran1fer. NACA TN 3104. 1954.

122. Cole,. W.D.: Experimental Determination of Thermal Conductivity of NBl-73066 Low-Den1ity Ice. NACA TN 3143, 1954.

123. Col••• W.D.: Icing Limit and Wet-Surface Temperature Variation for Nal-73014 Tvo Airfoil Shape • under Simulated High-Speed Flight Condition•• NACA TN 3396, 1955.

124. von Glahn, U.: Preliminary Results of Heat Transfer from a NBl-73148 Stationary and Rotating Ellipsoidal Spinner. NACA RM E53F02, 1953.

Miscellaneous 125. Gray, V.H.: Correlation of Airfoil Ice Formations and Their NBl-73015 Aerodynamic Effects with Impingement and Flight Co,· dit ions. (Presented 1957), SAE at the SAE National Aeronautics Meeting - Sept. 30 - Oct. 5, Preprint No. 225. (N-56390)

f

126. von Glahn, U.H.: The Icing Problem: Current Status of NACA NSl-73016 Techniques and Research. (Paper presented at Ottawa AGARD Conference), June 10-17, 1955. AG l9/P9. (N-37766) v~n Glahn, U.H.: Some Considerations of the Need for Icing 127.

Protection of High-Spe~d, High-Altitude Airplanes. NACA Conference on NBl-73031 Some Problems of Aircraft Operation, November 17-18, 1954. NASA TM X-54700, pp. 21.1-21.7. (N64-85274) 128. Lewis, W. and Perkins, P.J.: A Flight Evaluation and Analysis of NSl-73017 the Effect of Icing Conditions on the PG-2 Airship. NACA TN 4220, 1958.

Icing Conditions to be Expected in the Operation of 129. Lewis, W.: N81·73289 High-Speed, High-Altitude Airplanes. NACA Conference on Some Problems of Aircraft Operation, November 17-18, 1954. NASA TM X-54700, PP• (N64-85274) 20.1-20.9.

130. NACA Conference on Aircraft Ice Prevention. A compilation of the NBl-73018 Papers Presented by NACA Staff Members. june 26-27, 1947.

(6505/NACA-1947/8) 131. Gray, V.H.: Heat Requirements for Ice Prevention on Gas-Heated NSl-73056 Propellers. (Presented at SAE Annual Meeting, January 9-13, 1950), SAE Preprint No. 424. (1201.11-203) 132. Bowden, D.T., Gensemer, A.£., and ~peen, C.A.: Engineering Summary of Airframe Icing Technical Data. Federal Aviation Agency, FAA-ADS-4, 1964. AD-608865 (N65-10209)

ss

SUMMARIES/ABSTRACTS OF DOCUMENTS

LISTED IN BIBLIOGRAPHY

Meteorology of Icing Clouds

NACA TN 2738 National Advisory Committee for Aeronautics.

A PRO8ABILITY ANALYSIS OF THE METEONO- LOGICAL FACTORS CONDUCTIVE TO AIRCRAFT ICING IN THE UNITED STATES. Wtlliam Lewis and Norman R. Bergrun. June 11152 . 113p . dia1rs ., 11 tabs. (NACA TN 2'138) Meteorological Icing data obtained In flight l.n the United States are analy~ed statistically and methods are developed for the determination or (I ) the various simultaneous combinations or the three basic Icing parameter s (liquid-water content, drop diameter, and temperature ) which would have equal probability of being exceeded In flight In any random icing encou.n- te.-, and (2) the probability or uceed i ng any 5Peclrted group or values of liquid-water contert a ssoci ated simultaneously with temperature and dr op- dlame:er valu es lying within spectrled ranges .

met".od provides a convenient means of calculaU..

the per.:entagt ol icing encounters ln which the water collectlon rate uceeds the destcn nte.

NACA TN 25H National Adviso ry Committee for Aeror.autlca.

A SUW.URY OF METEOROLOGICAL CONl:ITIONS A&lOClATED '1.1TB AIRCRAFT ICING AND A PRO- ~ r: o ME'n!OD OF SELECTING DE~IGN CRITE- RION S FOR ICE-PROTECTION EQUIPMENT P111tl T. Backer and Robert G. Dorsch. Nonwber 11151.

35p. dia1rs. (NACA T!\ 25e9) Data on the m te orologtcal panmeters pertinent to th e aircraft lcU1g problem are ao amuna rt&-4 u to 1tve the frequen cy of occurrence of obae"ed icing situations ac cording to two al the parameters. TIie SUIJl11' arl:ted data lndlcate that :.u.Ustkal relations exist between aorne I the panrnetus . A method, ba t1 u;iuu the collection e!Clclenc:, of an alrfoU and the frequency of occurrence al Icing 11ltuaUon1 with nrioua llquld--ter cCW1tents and mean-effecth'e droplet li&es, Is propoMd for the selection ol de11Jn crlle rlons for Ice - protecti on equlpmeat.

...... ~~--.- ..... ---·-.........-,...- .....

NA'l'IONAL ADIIBORY Cot.f-tl'l'.l1'Z FOR AIROMU'J.'ICS TECHNICAL NOTE NO. 1855 ll'COM-!ENDED VALUIS 0.1' MITIOBOLOGICAL lACmE TO D COEl.lERED D ml IISIGll 0.1' AIBCBArT IClM'BIVD'l'IOB IQUIPMD'l' By .Uun R. Jones and Willla Levia Meteorological condi tiona conducive to aircraf't 1c ing are arranged 1D four claaaif icationa: three are associated vi th cloud structure and the fourth with freezing rain. 'lbe range ot possible meteorological factors for each claeeU'ication 1a discussed and specific values recommended for consideration in the deai91 ot ice- prevention equipment for aircraft are selected and tabulated. !I.he values selected are ba~ed upon a study or the available observational data and theoretical considerations Where observations are lacking.

l

Recommendations for future research in tile f'ield are presented.

,i Investigation of Mateorolog1cal Conditions Associ- ated v1 th Aircraft Icing 1n ~er-~ Clouds for 1947 -48 Winter.

B1 Dwisht B. Kline

1IACA m Bo. 1793

Jamar, 19,9 Meaaurement • of 119.·1114-vater content, 4rop ai1e, u4 teaperature 4m-1Ds 101111 oolll1t1cu enoom- tered 1n fiSght are • hon to 'be oona1 • tent vlth ,n- Tioualy aea1UN4 ocm4it1ona an4 vitb propo • ec1 -.xlmlll iaiag comitiona in auperooole4 la:•r-t1P9 cloud,.

C11mlat1Te-fretue11CJ srapha ot •teorolos1aa1 pu-a- •ter1 are pre • ente4 11111ce.t1ag the !"requeac7 with which T&rioua 1oilts ooalitiona ha~e been eacounter•4 1n tbe Great tab • area and eunoUD41Jtl at.ate • 4ur1Dg tllo vintere or n.1pt o'b • enatlcma.

---""""""---.,,-""""""--~--- --- .-----

Meteorological Analysis of Icing Conditions Encountered in Low-Altitude Stratitorm Clou4a.

By Dwight B. 10.ine and Joseph A. Walker

BACA !1'J 2306

!larch 1951

'

" ,.

Abstract \ Liquid-water cor:tent., droplet size., and temperature ~ data measured in predominantly stratitorm clouds during the 1948-49 and 1949-50 Winters are presented. The hori- zontal and vertical extent ot icing conditions and the relation ot the existence ot supercooled clouds to cyclone areas and precipitation regions are indicated.

Liquid-water content measurements during 12 tlights are shown in relation to theoretical amounts calculated trom radiosonde data and cloud depth observations.

NATICNAL ADVISOP.Y COMMITTEE FOR AEROHAtr.l'ICS I ICING PROPERTIES OF NONCYCLONIC WINTER STRATUS CLOUOO By William I.ew1a, u.s. Weather Bure.au SID.Cl.ARY ~ Measurements ct the vertical d1str1but1on or liquid water concentration and drop size have been made in winter stratus clouds in the absence or s1gn1t1cant cyclonic or trontal activity. 'lhe obaervations indicute that the clouds are formed by turbulent mixing or the lower la7era or the atmos- phere, res'.lltin~ 1n a region or constant apec1t1c humid1t7 al'ld adiabatic la~se rates. Calculnt1ons baaed on these character- istics Nre uset: to construct a graph which g1 ves the liquid water c~ncentration 1n tems of the tenmerature at the cloud base and the height above the base. In.clouda trom which no anow was falling, . the measured values were. ln good agreement with those given by the graph. Snowfall was round to deplete the liquid water content eapeciall71n the lower part of the cloud la,er, causing dissipation of the cloud from the·baae upwards.

S8 ,.

rs It ,. s n a S5l I 7 2 5

""'""•""'™..,"t.-.'fl""II"'\ ~--;•"" .. .:--.,;_tf"...,...~·""'' ....,,..,..,.,,~.;._;_,μ -IS """"":11,~•:)'"'_i:"'4•. -"!'.t'"'"'"-*""'· ••CtzlWP"IIIIIQ¥1111'1. """qzr,;•,..,.,...,.,..., •. ,'"'.". •""'"......,,..( ........_...,_..,...-r -.~-"7"~_,,..-_-_ .. _,..._·~_,., .• - .. ·--· ._ .. _.,. __ .. -_·· ..... _,._-~_-=--· -------- Obaervatiou ot Icing Con41t1ou Bnoountere4 1n ~ 7

Plight During 1948. ·

By VUliam Levis and Walter H. Hoecker, Jr.

BACA '1'B 1904 June 1949 Abstract Meteorological 4ata from i.c> tligbta in icing conditicma are presented. The report also includes a discussion ot the relation between the horizontal utent ot icing conditiona and the average liquicl- vater content observed therein, the rel1ab1lit7 of· tligbt meaaur•ents ot drop..eize distribution, and an apparent geographical 1ntluence upon t~e size ot .cloud Grope.

I • 8 A Furthe~ Investigation of the Meteorological Ccmd1t1ona Conducive to A1rcrart Icing By William Lewis., Dvight B. Kline., and Charles P.

Steinmetz NACA TTf No. 1424 Ch:tober, 1947 1.i AbstrJJ.ct d H !1 /.

Datit fro:1 tl1.gbt obeerYationa in 1c1Dg cond.1 t1ona il :m liquid \Ater content, temperature., and •m-ettectiYe lrop dhmeter are ahovn to be conai • tent With prenou • ~ ~opoaed. Talue •• Data an drop-,aize 41.-tribution With the rotat1ng-c7lind.er method, al though con • i • tent V1 th ;,rertou.e data, were incou • i • tent with 4.ata 4er1Ye4 traa 1tatiO!l!U"7 c111nder 1nTe • t1gationa. The rel~tion betv.Hm :aperature and :am:!mua water content 1n la,er clouda 1• U • cussed and e • timatea are g1 Ten tor the h1gbe • t Taluea >t water to be expected 1D la,er clouu at Tar1oua t-,..

,raturea.

... -~~---~ .. ~~--~-- ,_,,......, ____ __

l 4 I w w aw. ; ;o;; ,- .. ......,.,,..,,..,..,~.a-"1,1!1!1 . . ll!!lf ..-.a.CJ1!11711Pi " MCA RM IIIJOI lfatloall Adfl10r, Comm ..... for Aeroaalltla.

PRBUIIINARY 8URVSY OF ICINv COMl>moNS MEASURED DURING ROUTINE TRANSCONTINSNT• AL AIRLINE OPERATION. Porter J. Perl&lal.

December 1111. l'fp. diqra., pbotoe., a tabe.

(NACA RM SHJOI) Iclnl data collected on rouUae aperatJoM bJ four DC-4-type tnnaport urcraft eqldpped wWl NACA . press11re-type lclnl•nte meter, and OJlal over a tranaconUnemsl rollte from JUll&J'J throup May 1151 are preHltecl. Tbe four aircraft were IA lcJIII conclttlons approxlmalely l•l/1 percent ol the total Dyllll tune. Nearly oae•balf of the iclnl coaditlona were encow.terecl Oftr tbe Gnat Lakes area.

Avena• llqllid-wuer-conteit mua11rementa did not uceed l. 0 1ram per cllblc meter and 80 percent ol the meanremenw did not eaceecl O. 4 1ram per cllblc meter. Tbe data are considered only preU.laary and the pqnm ls contlnlllnl to proVide addlUonal data from world-Wide air routes.

10 NACA RM E55F28a National Advlaory Committee for Aeronautics.

STATISTICAL SURVEY OF ICING DATA MEASURED

ON SCHEDULED AIRLINE FUGBTS ova TU

UNITED STATES AND CANADA FROM NOVEIDD 1951 TO JUNE 19$2. Porter J. Perk111s.

September 1155. 44p. diagra., pbotos., 2 tabs.

(NACA llll lHF28a) A statistlcal nney and a preUminarJ ualyaia are

made in an iiterlln report of ove1 eoo lclnl ea-

cOIIDlera obtained from a conllnlWII PfOll'Ul sponsored by tbe NACA with I.be cooperation of the airlinH. PrNaure-t:,pe iclntl-rate mtt•r• were la• stalled on 11 airline aircraft of varloue type,. lclnl conditions m .. ured durl.nl scheduled aperaUou pve relative frequenciea of liquid-water coateat, lclng rate, total lee accumulaUone, cloud tempera• ture•, u well u hori&ontal and vertical extent ol lclng clo\Mla. Liquid-water content• •ere higher than data from earlier re11arch Cllpt1 ln layer-type clo\Ml1 but sligt-•ly lower than previoue data from CIUIIWIII clouda, ----......_~.....,. ..... ·c.. .. -.........._____________ I 6, OM # ?s:dtr Ch $

NACA TN 4314 NaUOnal Advlaol'J ComllllttH for Ael'CIUUdca.

ICING FREQUEHCJES DPIRJENCa> DURING

CLIMB AND DDCENT n FlGHTIR•INTERCEPTOa

AIRCRAn. Porter.I. Penln1 . .1111, JIU. aop.

dlqr1., taut. (NACA TN DH) Relative frequact11 of occurl'eftce and • -nl'UJ ol tctna clowl la7er1 eacountered 1111 to aa altltllde al 30,000 ftet are pre1111tec1. .Jet flllllen oa l'OIIUae operaUOcaa ol the Atr Delanae Command (USAF) MU' · D11l1&tb, lllnne • ota, UICI Seattle, Wulllnpon, wen eqlllpped wlt!I tclDa meter • for l Jeu. lclal oeftrnd on appn,ximately I percent of the fllllall, wltJI lee• accreUoo Wclme • a averapn1 le • a Ulan l/11 lacb OD a amall 1enaln1 probe. ProbabWUN of Ida, NYer• !ty (lncl11cllq averap Uqllld-11aler eootent and mul• mwn ice accretion) were ea1C11lalecl ualn1 earller data meu11red ln lc1n1 clouda.

' 12 NACA RII BllDll National .\dftlOIJ Commllt• for -- • atlCL

ANALYIII or IDT&OROLOOJCAL DATA 08-

TAINBD DUIUNO FUGBT DI A avpacocx.m,

ITRATIFORII CLOUD or BIGB UQUID-WATD

CONTDT, Porter J. Pslldu ad Dwtpt 8. SU..

- 1111, lip, dlasra., pbatoL (1'ACA 811 SllDll) Pl1lbt 1cilll•rate data olltalDed la a ... ad llmor• sully deep • upercooled • traUform cload .,.._ ta tu nciftit, ol Lue Erie llldlcated tbe mlhDCe al

Uquld-water caat-• swrallJ aceedllll ft19N ID

amoat and ateat pnYlaualJ npol'ted onr tbe mid· Wilen NCUou cf tile United ltateL Addttt«.I ildormatioll obt.a1ned du1ac deeca throap a put al tu doud IJltelll Indicated liqulcl•water CClldmtl Ulat atpWcantly eacNded tbeoreUcal nlue •• -,.d1U, near tile mlddle cf tbe cloud -,er.

w • tree

IIACA'l'IIIIM • .-aw--,cw-efflee•Aclliillllll.

ffATll'l'ICALft'UDT 0, .AWIT ICIIIO ,_.

AalUl'III A.TTD --AIID--W!dBta a.Y• 1uonaOCURADMDlftl.., ...

DIIIIPDU. Poner J ....... wuuaa .......

llldDouldR. lldollud, Ila, IIIT, llp. dlaln,, tul, (NACATNNN) It ll&UIUe'II...., la .... ol lelal ........ n- portad from ,,......r n-,ee•ce alnnft Don '7 Air Weatber lenk• (UIAr), Wide anu or a.

PacHlc, Mllalle, aad A.retie ac.... WN w,-,_.

at,._ llflM •• ol IIIO .. (ll,- ft) ad tlO lllt

(lO,- ft). lcfDI ....,_,. pn1lll1ll faclllll tlle NIIUft lnqll•clN ol lie OCCVNIN ol lclll, tlle

...,_, ... pl'OIIIIIWtJ of-- fa leflll, aad lie N•

laUDII ol lMN ~- to tlle IN..-c&• ol llfpt fa Claud • ud doad ............ ldalpnlt-

lbWUII ftl'ted widely lbroapMat tbt,..,. from HU'

, .. ro In cold Arctic areu In Wiater 1111 to T perem ta .,. .. -• re sreater elotadfa111 IDII war•r tem• pentllnl preftil, NASA 11£110 1•11•59E NaUonal Aeraullllca and Space Admflllltratloll.

IUIIIIARY OF STATISTICAL ICING CLOUD DATA MEASURED OVER UNITED STATES AND NORTH ATLANnC. PAClnc. AND ARCTIC OCEANS DURING ROUTINE AIRCRAFT OPERATIONS.

Porter J, Perkin •. Janll&l'J ltlil. llp. 111111'•·• pboto1., tabe.

(NASA IIEIIORANDUl4 l•lt•ltl) Dita ull atat.lltlc • aeedld •• urenft ••• ud openUOD an pre1111ted from 1c1111-eloud .....,. ..

meat, • ad obee"atlona oblalaed dlarlnS an ••N • ln

''°''am conducted ln cooperation wWa anenl ur-

Une1 ull tbe Unlted State • Air Force. kla1 meter • laltalled on 71 H"lce alrrrlft • uppUed lnlormatlon for determlnln& the Uqllld-water c:ontnt ud dllllMCe traveled ln UOO icing-cloud enco11nter •. Otber lclns•t'loud parameter • meu11rld wen the tempera- t11re and depth of irtnc•cloud layer, and a reference :j total lee accretion for ncb encounter. AU re • wla • !

are tabulated and tbe meuured parametera are IIUmm&rl&ed u frequenc:y dlltrilNUonl,

""' • μ Pfll W&J¾ • ~--- ....... ~ •• - ... , .............. -- ... ·--··~- •IP4jW-- -----.~· -,....,. .. .,. ...... ~--~----- ..... ~--- r"l!',_...----r'.

···---·---•4

----~-- --··

Fundamental Propcttiea of Water 8tat1 • t1cal hplanat1on ot Spontaneous Free&1D& ot Water Dropleta.

11 Joeeph Levine -.

(t BACA 'Bf 2234 • December 1950 Abstract A atat1at1cal theor, baaed on the pre1enoe ot aal.l.

cr,atall1&ation nuclei suspended in water 1a developed to explain experimental reaul ts showing that on the averaae aill81.l droplet • can be aupercooled to lower tem- peratures than large ones. Sm.ell nuclei ot cr;yatal.11- zation are aaaumed responsible for causina supercooled water to freete apontaneoualy.

The average behavior ot supercooled droplet • 11 reproduced on the baa1a ot probabi!it7 the01"7 vith an aaaumed diat1~bution of cr7atallization nuclei vith reapect- to the temperatures at which the nuclei cause freezing. The moat probable cUatrH,ution curves ot apon- taneous freezing temperatures tor water droplet • or various aizes within the a1&e r8IJ6e f.ow:id 1n clouds ere obtained.

16 Photcaicrograpb!c Investigation or Spontanewa

J.l'ree zing Temperatures or Supe1-cooled Water Droplets B7 Robert G. Dorsch and Paul T. Racker NACA TN 2142 July 1950 Abstract Data obtained b1 a pbotomicrographic technique on the spontaneous freezing temperatures of supercooled water dro;;lete of the aize ordinarily found 1n the atmosphere are presented.

The epontaneo·..is freezina temperature vaa ro-..ind to depend on droplet size.

~~~~ncy distribution curver of the aponte.neoue freezing temperatures ohened for a given e1.ro11let size were obtained.

-~·1· • l11d'1K"· . -- • '&

;a J _Y.Mfl"----·-•-uw ..... - ...... ...,-,,- -;-; __......,,,..,.~,.,,_....,_ ... , -, .... _....,,""' 4 ""4" • .. _ ;.-i,,...,._..,_ ... ,~ ..... __,,....,--.,..-- -,..,-T..,.~---·- -, NACA TN 1,:10 Natlolal Adfttlll/rf CommlltN for Aer...UCa.

UPEIIMENTAL VALUES OP 1IUt ~PACS TElelON OI IIJPERCOOLED WATER. Paul T.

llacar. October 1111. JOp. clap'a., pbotoa., tab.

(NACA 'rN 1110)

TIie IIVlllc• teaalall al wta luia ..._ --•laid

-,.rtmeltallJ for UM tempentare rup, fP to

-D.J'> c. TIie ~ Lnfledlall point Ill tbe ...,.ce-

teukla - tempentun relaUon, aa IDdlmted bf U.

lateraaUanal CrtUcal T1lbl• nl•• for t.a,eram•

down lo -f/J C, •• aul•uUated bf Uie meaaare- lDIIIIU Ill tlM tem .. ratwe ft .. , 00 to -11.IO C. ffN aurtace t.ulon lntnun at -..,rodmatelJ a U...r nte from a ftl.:e al 'NI.N~.oe dfM• per ceallmeter at -to C to '11.l'lto.OG dJDea per centimeter at -22.Zoc.

NACA TN 2532 National Advlaor, Committee for Aeronautics.

X-RAY DIFFRACTION STVDY- OF THE INTERNAL STRUCTURE OF &UPERCOOLEO WATER. Robert G, Dorsch and Bemroae B<1yd. October 1951. Hp.

d1a1ra., photo. (NACA TN 2532) X-ray diffractiou data for water In the temperature ranee 21° to -111° Care presented. "r.11e minimum between the hrr.> main diffraction pealta deepened con- Unuoualy, u the temperature was lowerec!. n la concluded that aupercooled water apparenUy become• proerustvely more Ice-like 1n structure•• the tem- perature ls lowered.

19 NACA 11M SllLIT

NaUoal......., Coaalltee for Ae....-aa.

A PHOTOGRAPHIC ffUDY OF n&SZDIO OF WATSll DROPLrn FALLINQ n&SLY DI AIR.

ltobertO. Doncllud.JONpllLmM. r__,.,

1111. n,. dilln,, pllo&N., I &IN. (NAc:41111

Slll.lT~ fte fne&IIII ol fne-fallial ftler draplata • a&r wu laffatlpl..S bf a fliatolnplllc ,...._. Woraa- Uotl OIi Ille followlll WU olltalaed: (I) draplat .....

l

after fnea&as, (I) tM occvrwe o/. coll•--• ol

putlJ fl'OMll or lroua 11111 Uqald draplata, ud (I) tbe frtieaas temperature• ol ladlndlaal ''""' fall&nc dropleta .

l

•

20 NACATN 3024

National Ad,taor, CommlttN for Atronautlca.

MAXIMUM EVAPORATION RATES or WATER DROPLETS APPROACHING OMI'ACLl:S IN THE ATMOSPHERE UNDER ICINC CONDrI'IO ...

Herma• H. Lowell. October 1153. Hp. dla1ra, 1 I taba. (NACA TN 3024) Muun11111 poaalblt enporatlon ratea of water droplttl approad:lnr obttaclt1 In lht atmo-,lltrt alone atapatlon Uneaor movtn1 within lntau duct1 of airplane• under lclnc condltlona were calculattd for a wldt nrltty of ambient condltlona, fllpt Mach n11111btr1, d11r1ea of atapallon of tht Incident rell- tln air atream, and droplet dlamtttra. Droplet diameter, body alu, and fili)lt Mach number tffecta

w,,.. found to predominate, wb1r1aa wide variation

111 ambltnt condltlona bad Uttlt tfftct on tvaporatlfl louta. It wu conchldtd that Uttlt or no napora- Un loaa occura rrom dropltta approachln1 amall obetaclt1 auch aa llquld-watn-cor.tt'nt mnaurtm.nt cyllndtr1, •htrtal IOHtl JI\&)' bt H hlJh H atvtral ~rctnt In tht caat of lar~·tr obataclta 1uch aa wln,:e, or 50 ptrctnt Ir !ht ,•u•: d ducta at hl(h ram prtaaurt, Loaata In d11d1 In central, however, wUI uauaUy bt about 10 to 20 ptrc:?nt.

ti$ itt

__,,--"-·--n---=-·----•o-------------11!•11c!!.•---ll"J!!"l!'l¥1!1~~-

-i ~--~ ----------- '

Kinetic 1'empcraturc of Wet Surfaces

A Method of C..kubting tlk: Amount of Akohol Required to Prevent kc, and

the Derivation of the Paychromctric Equation

HJ

J. K. HA111n·•

of the Royal Aircril(t E.tabli.tamtnt Rtpor11 and ldtmoranJa No. 2830

&p1t1nl11r, 1945

s.un,,.,,. -A method is liven for wcwatin, the temperature of a surface wetted either by• pUR liquid, such

•

u water, or by a mixture, 1;1aeh as alcohol and water. Tht method is applied to the problem of protec:tin,, by alcohol, propellers and the induction system or the cnsine ap:nst kc. The minimum quantity or alcohol reqllired II calcnlalcd for a number of arbitrarily chosen condition~. The cffec:t of evaporation of ak:ohol Is shown by repeatina tbt calaalations for a non•YOlatile nuid. The metbt:>d can be applied to otha problems ir. evaporation, for laatanc:c, to the evaporatie>n of fuel in the induction system of the en,ine. The psychromctric equation, ,ucd in wct-blllb hypometry, is deduced in its acneral form. The effect of kinetic hcatina is incl~dcd in this equation.

Meteorological Instruments

NACA TNH15 National Ad-rlac>l"f CommlttH for AeronuUc:a.

THa. ~.t .. '.-CULATI.D A..'ID MI.AI\JRED PERFORM- ANCE CHARACT'ERJSTICS OF A HIATID-WD\.!

LIQ\::0-WATlR-COJIITENT MITER FOR M&41UR·• ING ICING U:VERrrY. Carr 8. NH1, Jr. aw.I Charlt • P. 1te1Amet1.. January 1951. Hp . .11a&r11,, photoa., e t&bl. (NAC~ TH 261$) ln.itlal developa1ent hu been made of u lllanmaeat which cOl&ld ti. llNd to obta.n 1laU1Ucal flicht data on the Uq11id-•ater content of tctnc cloudl ud to provide a direct lndkaUon of lctnc M'fertty. TIM Nn•inc element of tht tilltrwnent coaallla of a WI of known tetnperatw-t•rHlatL"ICf characttriltkl which 11 huted bJ Pf.HUii elfftrlca.l currwr.: tllroup U. Tbe win 11 mvwited ill the air •r•&n1 and th• decrH of coolinC , .. llltln& fro1D eva,oraUoa of illlpinc.llle water droplet• ta a mtaNN o( Ult "4Wd· water tot1ttnt of the clOt.1d Compartao,ui ar• made of the Uq1dd-water COfttent H mnMNICI w1UI IM&tad WiNI ud ablOrbut cyltndtra IA UI artUldally prodlm1d dOIMS. Perlormuce c1111ractertatic1 ot a healed-WU-I WU'Ullleftt &H preaented.

-~-' ... -------- .. - ... c:::-::.,.. .... , __ ............ -•e....itr.-11n1111i11<ri.J;!l10..-&----- -· --------------

.. -- -- ~~.!.J

23 NACA RM E53D23

National Advi10ry Commlttee for Aerouutica.

PROCEDURE FOR MEASURING LIQUID-WATER CONTENT AND DROPLET SIZES IN SUPERCOOLED CLOUDS BY ROTATING MUL'!'lCYLINDER METHOil WUllam Lewi1, Porter J. Perk.Ina and Rinaldo J.

Brun. Appendix C: ALTER.-.ATE METHOD OF REDUCING ROTATING MULTICYLINDER DATA.

Paul T. Hacker. June 1953. 48p. diagra., photo •., 4 taba. (NACA RM E53D23) The rotating multlcyllnder method for in-night deter- mination of liquid-water CO'ltent, droplet 11..&e, and droplet-alze diatrlbutlon in icing cloudl la described.

The theory ol operation, the appar ..i.us required, the technique or obtaining data in flight, and detailed methodl of calculatln~ the re1ult1, including neces- sary charts and tables, are presented.

NACA RM E50K01a NaUonal Advisory Commlttee for Aeronautics.

FLIGHT CAMERA FOR PHOTOGRAPHING CLOUD DROPLETS IN NATURAL SUSPENSION IN THE ATM();PHERE. Stuart McCullough and Porter 1.

Perkins. 1une 1951. 23p. diagrs., photos. (NACA RM E50Jt01a) A camera designed for use in flight has been devel- oped by the N \CA Lewii. laboratory to photograph cloud droplets in their natural suspension in the atmosphere. A magnllicaUon of 32 times ts em- ployed to distinguish for measurement purposes all sizes of droplets gr~ter than 5 microns in diameter.

Photographs can be taken at flight speeds up to 150 · miles per hour at 5-second intervals. A field area ol 0.025 square inch ts photographed on '1-incb-wldth roll film accommodating 40 e:q,os-.ire1 on an 18-foot length. Flight tests conducted ln cumulus clouds have shown that approximate droplet-size distribu- tion studies can be obtained and that studies of the mlcrostructure and physics of clouda can be made with the camera.

J'l1aht Inatrument tor Measurement of Liquid.-

Water Content in Cloud • at T•perature1 above

an4 below :rreezins.

B)- Porter J. Perltina BACA 111 150012a 11arch 1951 , .

-

'

Abstract An inatnaent conaistins of a n.all cylindrical element operated at high surface temporaturea was

dneloped to provide a ailllple aDd rapid means ot deter-

mining the liquid-water content of clouds at tempera- tures above and below treezina.

The instrument V8S sensitive to a vide ranee of

liquid-water content and was calibrated aeainat rotatins

•~tiqlioder meeauremente at an air temperature or

20 r, an air velocity of 175111.ilea per hour, and a

surface temperature in clear air of ~75° F.

26 NACA RM E51E16 National Advil'Ory Com· .ilttt>e for Aeronautic:&.

A SIMPLIFIED INS'IRUMENT FCJl RECORDING AND lNDICA TING FREQUENCY AND INTENSITY OF ICING CONilTIONS ENCOUNTERED IN FLIGHT.

Porter 1. Perkins, Stuart McCullough and Ralph D.

IA"wis. 1uly 1951, 26p. diagrs., photos. (NACA RM E51E16) An instrument for recor<iing and Indicating the fre- Qllt'nt'Y iind intmsity cl airrraft klrc conditions en- counll'Ud In flight has bffn dl'veloped by the NACA I.A-wls Laboratory to obuln statistical lei~ c!ata OVl'r world-widt air routes during routine airline ~erattona. Tht opt'ratlon of the instrument ls bas~ on U.. crutlon <I a dlfferenUal pressure be- hrttn an icl'-frt't' tatal-pressurt' system and a total- prtssurt' systt'm In which small total-pressure boles vented to !Italic pruS11re are allowed to plug with lee accretion. Thi.' simplicity of thh operating principlt' permits automatic operation, and providrs rebtiVt' freedom from malnttnanct and q,eratlng problems. ThP complete unit welghlnc only 18 poWlda ffCOrds Icing rate, alrapeed, and altitude on photasraphic film and provides visual 1Dd1caUon.& of lcin& intenalty to the pilot • .,.

-~ ...... ,-,--.--., .. , '.,., __ . .._ ____ ,....., __ ·"'""""...,_....~----·....----,--- t I

27 NACATNHII

National AclrillOl:J CommlttH lor Aeronautic •• AN INITRUllll:NT 11:MPLOYJNG A CORONAL DIS-

CHARGE FOR THE DETERMJNAnON or

DROPLll:T-81ZII: DISTRIBUTION IN CLOUDS.

Rinaldo J, 11nm, JONpll Lewlne, and Kennetll I, Kleinknecht. a.ptember IHI. Hp, dlarra, photo •,, 4 tabs, (NACA TN 1411) A Ollbt ln • trument tbt ll • H tlectrlc mean • for ' obtalnlna a QIIISllJ'e ol the droplet- • 1&1 dlatrlbutlCXI In aboYe-frHalna cloucl • b •• been devillld and IPYeD

preltmlnar, enl-.-...tlo11 In flllht. An electric chars•

la placed on th• droplet• and they are aeparat.cl Hrodynamlcallr acco...U. to their mass. Tb• de- alrable laature • of • n lnatrwnent baa.cl on the method de • crlbed are: (l) the Instrument can be u • Nl In clouds wttb temperatures above free&lnl, (I) the alH and the shape of the cyllnders do not cban,e durln& the eirpo1111re time, (3) tbe error caused b)' bowlce-off la low, (4) the readlnc• are 1:istantaneous and continuous, and (5) the fast lnatrument response permlta the study of variations In cloud structure.

28 NACA RM E51G05

National Advisor, Commltte-e for Aeronautics.

ADAPTATION OF A CASCADE IMPACTOR TO FLIGHT MEASUREMENT OF DROPLET SIZE IN CLOU~. Joseph Lf'vlne and Kenneth S, Kleinknecht, September 1951. 28p. dlagrs., photos. (NACA RM E51G05) A cascade impactor, an ln!ltrument for obtalnlna the size distrlbuUon of droplt-ls borne In a low- velocity air stream, has been adaptt'd for flight cloud droplet atlldiea. Data from two lllgbta are presented.

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:

.. £WA ½<i..~.~- EEf 141 • & • Lt 4Miiil&

·· . ""btJS!]

NACA TN 2'108 National Advl10ry Committee 1or Aeronautlc:1 .

.:OMPARISON OF THREE MULTICYllNDEA ICING METERS AND CRITIQUE OF MULTICYLINDER METHOD. W11llau !. Ho-11, Mount W1ahl111ton Obaervatory. JW\e 1952. 40p. diagra., photo •., I tabs. (NACA TN 2'108) Three multlcyllnder lcq meters, fWldamentally atmUar but dlfferlq from each other ln important delsgn details, nre compared ln use at the MOWlt Waahllllton Observatory. Comparison of relative

\

effectiveness ol the lnstrum•nti, evaluation of obser- vational errors, determination of the eUecta of de- tailed design differences, and recommendation • for further improvements ol design are presented. An ·, evaluation of the multlcyllnder method, concerned with the validity of the theoretical basis and the de- gree to which the lnstrumenta and the technique of their use permit accurate determination• of t."le pbya- lcal mear.ll'ementa involved, ls alao included.

A Beviev of Instruments Developed for the Measurement of the Meteorological Factors Conducive to Aircraft Ici.1g.

B;r Alun :R. Jones and William Levis

l

NACA BM No. A9C09 April 1949 Abstract The statua of instruments suitable for the mP.aeurP- ment of the meteorological factors conducive to air~~aft icins ie reviewed. The factors to be evalustcd &rP.

listed, and tentative values for the ~GdirPd and accept- able accuracy of meaeurell16nt !Cf!' each factor arP- BUBSested.

Nine 1not.ruments vhich e.ppear to be thp, m:>at pronrte- 1~ for tha procurement or the meteorological data arP diecussei with respect to tbu quantities they mPaeurP, principle of operation, range and accuracy, du.~ation of a single readins, and advantages and disadvantagPe as~oc1- ated with their use. Recommendations are presented for the continued research a."ld development of ic1l'l8 meteor- ological instruments.

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NACA RMAHID National AdTl•Ol'J' CommlltN for Aeronautlca.

A HEATED-WIIU: LIQUID-WATER-CONTENT

lNITRtJIIENT AND RESULTS or lfilfl'IAL FLIGHT

TEBTI IN ICING CONDfflON8, Carr a. Neel •

.lu11ary llH. Hp. dlqre,, photo • ,, lab. (NACA RMA541JS) A Olaht model of the h•ted-wlre lnetl'Ulllelll wu teated ln natw-al lclnc condlUona, and wu llhown to proride reliable meuurement1 of Uqwd-water content. The rapid reeponn of the l111tnameat enabled detailed atudy of cloud atnacture. Cloud- chct teeta allowed mea1urementa could be made "1 to 100 mph. Reel&lta of the fillht meuurement1 • ub- lltanllated the hip value • of water content prevlouly predicted. The hlpeet walue meuW'ed wu S. '1 tram• per cubic meter, NACA TN 35112 National Advl • ory Commlttff for Aeronautic •.

AN OIL-STREAM PHOTOMlCROGRAPHlC AERO• SCOPE FOR OBTAINING CLOUD LIQUID-WATER CONTENT AND DROPLET SIZE DISTRIBUTIONS IN FLIGHT, Pa11\ T. Hae lier. Jan11ary 1H6. S6p.

dlqre., photo •., tab •. (NACA TN HU) An airborne cloud aero1cope by which droplet IIH, al&e diatrlbuUon, and llqutd-water content of lcinJ and nonlcl111 clouda can be determined bu been de-

l

veloped and luted in nt1ht and In wind tunnel • wlUI water apraya. The cloud droplet • are contlnuoualy captur.«S ln a atream of oil, which ta then photo- • . l sraphed. In moat caau, droplet 111.1 dlatrtbutton can be obtained from a • ir,ale photosraph. With Ule droplet • lz.e d11trlbut1on llnown, the liquid-water content of I.be cloud can be calculated from Ule p- ometry of the aero • cope, the alrapeed, and the oll flow rate, The aeroacope ta de • crlbed 1n detail, and tome droplet alu dl1trlbutlon1 and liquid-water content• obta!.ned during teeta are preaented.

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--.VJ .,..,--- .. ------- .... __ 4'y'O.,.......

Impinaement of Cloud Droplet• 33 MCATNM'9 Nltkaal Mil-, Qamltteef• ....UC..

.AN mlRRICAL MSTBDD PDlfl"nND IIAPID Dn'aMINATION a, 1BB Alll:A., un, AND IIBTIIBU'IIClf 01' WATBR-IJROP DIPINOBIIBNT ON .AN AIRPCIL 01' AIUIITIWIT ISC'IICIC AT

~

IUIIICINIC .. Bal: NoNu L ....,_.

· llptmber ltll. lllp. ....,._, 11 tabL (NACA TN M'II) A•--ladnelaped'llllldlpendlatlle.._lM• Uoll or ..... , nte, -· altrlblltlml ol wter-4np ~t • alrtol1 • ol ullltnrJ NCtloD at adt-

• -c ........ TM mllbad, wlllcll l • lued • tllle

naaltl of ateulft •ts-dnp~--, calcala• Uou f• ftff airfoil C&HI, reqainl cmlJ a few • lmple -•teal ccaputatiou as• tbe ftloclt, dlatdbutloa o._ tbe airfoil la • ... detsmlaed.

NACA TECHNICAL NOTE No. 1397 A METHOD FOR NUMERICALLY CALCULATING THE AREA AND DISTRIBUTION OF WATER IMPINGEMENT ON THE LEADING EDGE OF AN AIRFOIL IN A CLOUD Norman R. Bergrun SUMMARY A method is presented for determining, by step-by-step integra- tion, the trajectories of water drops around any body in two- dimensional flow for vhich the streamline velocity components are known or can be computed. The method is general and considers the deviation of the water drops from Stokes' lav because of speed and

i

drop size.

I The equations are presented in general form and then, to illustrate the procedure, water-drop trajectories are calculated about a 12-percent-thick symmetrical Joukowski profile chosen to simulate an NACA 0012 section • ..

The method provides a means for the relatively rapid calculation of the trajectory of a single drop without the utilization of a differential analyzer.

In addition, consideration is given to the maximum possible rate of water-dror impingement on a body.

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~ ' t ' J

ICACARMIUBll NaUoul AdYlaol'J Comm1ttee for Aero •llllce.

IIIPINQDIINT 01' WATIR DIIOPLITI ON AN

ICACA 11~=-AlllJ'OII. AT AN ANOLS or AffACK

or~. ,. aru, .roema. 1ua11a1u11

Oeorp J. lloalloe. llpteaaber 1111. 4'1p. dlllr•., tab. (NACA RM Sll811) Tile t~rl• or drapllte bl tbe llr OOWII pul ..

ICACA 111 •Ill llrfoll at aa upe or ltteck of ¥) .. ,.

dltermlMd. Tile collecUoa elllcieDcy, tbe area or

droplet lmplllpmetll, ud tbe rate of droplet implllp• aeat "n calctlated from tbe tn,JectorlN. TIiie re• eulta an appllClble IUlder tbe follo•IIII coadltlou: ebord leaplle lrom I to IO feat, altUlldN from 1000 to H, 000 feat, llrpluae lpNde from llO mllea per boW' to the crlUcal fllpl llac:ll number, aad droplet dlametere from I to 100 mlcrou.

NACATNHn National AdTtaory C01nmlltN for Aeroaa,uca.

IMPINGEMENT OF l'l.tOPLETB aN 800 Bl.BOWi WffH POl'ENTlAL FU:NI. Palll T. Hacar, Rinaldo J. Brun and Bemroae Boyd. leptember 1813. Hp. dlalra. , I taba. (NACA TN 1111) Trajectorlea were dltermlned for clropltta 1n air nowl111 throu&h 90° elbow, eapeclally dealped for two-dimenalonal potential motlon With low prelUIU'e louea. The elbow, were Ntabllahed by aelectlna u wall• of each eClow two atramUnea of the flow fleld produced by a compl .. potential function that eatabllahH a tltO-dlmenaional Dow around a IOO

bead. An unlimited mamber of •lbo" wltb alllhtlJ

different lhape1 can be eltabllahect by Nlectllll different pair • of 1treamllne1 u walla. The elbow• produced bJ the complea potential function aelected are aultabl• for UN 1n aircraft alr•tnl&u ducta.

The droplet lmplnpment clala derlftd from the trajectorlu are preaented alone with equatlona 1n a.ach a manner that the collectlon efflclency, tbe area, the rate. and the cllltrlbullon of droplet lm• Plnlemenl car. be cletermlnecl for any elbow de· flned by any pair of etreamllne• Within I portion of tbe now field eatablillled by the complea potential function. Coordinate • for aome typical llream•

Una• or the flow fleld and velocity component• for

Mveral point• alona theu atreamllnel are pre• HIiled 1n tabular form.

.P ¢4iQ.$ .. ¥1' '!!"" eapww 4M¥ . MCA Rept, Ult N&Uoaa. \dftaor, ComllllUN for Ml"OlauUca.

IIIPINODISNT Of' WATSR DROPLITI ON •w•IDOII- ..

AND DOUBU•WSDOS AIRPOILI AT IUPERIONIC IPEID8. Jobll 8, StraflaL IIH. U, 14p. dlqra,

(NA.CA Rept. UH. rormerlr TN nu)

An ua1,uca1 IOlllUOII hu been obta1Md for the eq.UOU ol motloa of water droplet.a lmp1Dlbll on a ftdp In a two-cllmena!onal auperaonlc flow field wWa a abock wan attacbld to the wdp. 'l'ot clolld-lorm aolUUon ,telda analJUC&l up, ... ._.

for 1111 equaUon of the droplet trajector,, tM local rate ol lmplnpment and the lmplftpaaent ftloclty at an, point on tile wedp alll'face, ud the IOtal nte of lmplnpment. The anal,Ucal npree11ona are IIUUnd to determine the laaplnpment on the for- ward aurface• of dwnond airfolla in -.rlOlllc flow flelda with attached ahoc:k W&Yfl, The renltl preHnted include the followtna c:oaditlone: droplet diameter • from I to 100 mlcrone, pre•ure altitude• from ... lenl to 30, ~ feet, tree-atream lll&Uc tempent11r" from 420 to 490 R, fr .. •atream llacll nlllnber • from 1.1 to 2.0, 11,mlapea ancte• for tbe wedp from 1.14° to 7.t'l", WcknHl•to• cbord rauoa for the diamond airfoil from O.OI to 0.14, cbord leftllhl from 1 to 10 fHt, and an,lel of attack from aero to the inverae tanpnt of tbe alrfoll thlclalH••to-chord raUo.

'NACATN 3047 National Advleory Committee for Aerona11Uc1.

JMPINGEME!ff OF WATER DROPLETS ON NACA

85A004 AIRFOIL AND EFFECT or CHANGE DI ·

AIRFOIL THICKNES FROM 12 TO 4 PERCENT AT 40 ANGLE OF ATTACK. Rinaldo J. 81'1111, Helen M.

Clallqher and Dorothea £, Voet. November 1153. · 45p. dlagra., tab. (NACA TN 3047) TIie trajectorie1 of droplet• in the air Oowlng ~ an NACA 65A004 alrfoll ill an angle or attack of C were determined. TIie amount or water ln droplet form impinging on the airfoil, the area of droplet lmpln,e- ment, and Ille rate ol droplet impingement per Wilt area on the airfoil surface were calclllated from the trajectorlea and preaented to cover a large ranee of f\lght and atm01phertc condltlona. The effect of a chance ln airfoil thtckne11 from 12 to 4 percem It 4° an1te of 11ttack l1 preaented by comparing the lm· ptngemeru ralculatton1 tor the NACA l!>A004 airfoil with tlloat' for t~ NACA 651-208 and 151-212 air- foUa. The rearward UmU of implnpmeat on the -.,per 111rface decreuea u the airfoil thlckneN de• creue1. The rearward limit of llllplnpment oa the lower 111rface lncreue• wltb a deer .... in airfoil thlcluleaa. The total water llltercepted decreuea u the airfoil thicknna la decreued.

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IIACATNDU 'Na&lolal ..,._,, CWeldee lor Air rn.,ot

UPDIOSIUIIT or WATD D.,.Lftl OIi UCA

Ila-IOI AND 111•11' AIBJCILI AT • .AlfGL8 or

ATTACL ._.. ,. ana. aei.a II, Oe!'••

ud DorotMa a. TOil, llaJ llU, 41p. dllln-

(IIACA TN IIU) TIie l~torlee ol droplet• la tile air DoWlai ...

aa lU.CA 111·• urloll ud u MCA 111-Sll

· alrlol', llolllatuUlleol.aaaot•, .. ,.

coap1ledWUllaaecllulealualQI. TMUIOlllll ol waa.,r la droplet fora laptJIIIII oa * lirfoUa, ......... ol droplet ................. n&• ol droplet ----- per 11111& ....... urloU Nrfact, affected •re calclllllld from tM ~•- toriel.

kACATN H04 National Adn10ry Committee for AeronauUca.

111.PINGEMENT OF WATER DROPLETS ON A CYL• INDER IN AN INCOMPRESSIBLE FLOW FIELD AND EVALUATION OF ROTATING MULTICYLINDER IIE'fHOD FOR MEASUREMENT OF DROPLET-SIZE DlSTJUBUTION, VOLUME-MEDIAN DROPLET SIZE, AND LIQUm-WATER CONTENT IN CLOUDS.

Rinaldo J. 8r111i and Harry w. Mergltr. March

1153. 'lip. d1agr1., photo., • taba. (NACA TN 210,1 The trajectorl11 of water dropletl ln an tncompreNI· ble now field aro1&nd a cyllnder were calclllated w&th a mecbanlcal analOI, The coUecUon effldencJ, tile area of droplet lmplnaement on the cyllnder, and tu rate of droplet lmplnpment were determlned from the trajectorle•. An evahtatlon of the rotaUnc mllltl• cylinder method for the mtHuremelll rt dropltl•alt.e cU1trtblltlon, volume-median droplet 1lae, and liquid-water content wae ma~ baaed on the re111lta of lbe trajectory calclllaUona.

I

_____ , -· _____ ......._ ......... _~ ..... -- .......__..._.~ ......... -lilllall ..... ...._ __ _

1 tc ·;arc Si'?O CW# • I ;Or;wsd t eel +

IIACATIIIIOI 11.uo.l ~ 0-elttM w ,..,. •• ,.,.

IMPINOIIIDT 01' CLOUD DIIDPLSTI GIi MRO- HII.AIIIC IIODISI Al AfncTID BY COIIRl:II• IBILITY 01' AIR l'LOlr AIIDUND TU IIGDY, RIMI .. ,. ana, Mal. lenlllll ...........

Qallaper. March 1111, IOp, dlllrl, (MAC.A TN HOS) TM tn,leetorlta of water dropltll la a oompnPIIII•• · air Dow field aroud a cyllndlr nn -,.&ed wWa • aecllukal ualOI, TM rellllll of tlle Cllc:ulaUolll al u.. napt cntlcal llacb llllllllber nre compared wWa calculallona of tn,lec:torlta In u ~• now field. For a cylinder, tlle .aect of coaprer• lbllltJ of Ille air oa tbe droplet tn,leetorlN wu ...Slpbl• up to Ille ftlpt crltlc:al Madi ... r.

Tbe reeulta oblalMd wWa tile cylinder wen mended to alrfoU •. TIile uteuloa la poulble llecauN Ille lnc:ompre •• lbl• now flelcla of llolh cyu•r• and alrfolla are almllarly altered by compre11lblllty.

Dlterminatiun of Bate, Area, aa4 Dlatributim ot Imp1np•n.t ot Waterd.ropa on Varioua Airtolla trm.

'l'ra3ectoriea Obtained on the Dittenntial Aba]J&er•

B7 A. o. Gl..ibert, J:. Janssen, aD4 v. M. Bobbins

NACA RM no. 9A05

!'ebruaey 1949 Abstract The traJectoriea of vaterdrops in air flov1ng ovar airfoils are detnrmined for three airfoil - angl.e- of-attack combinations Wling the differential anal,yzer to solve the differential equat101:a of motion of the vaterdrops. From these traJectories the rate of water impingement, the area or impingement, and the distribution of impingement are determined as fWlctiona of two dimenaionleae moduli.

Comparisons are made of the rate of vater impingement on theae airfoils and the rate of vater !· impingement on cylinder,.

o~~C'~~{P.l PAGE •

OF , .. - . ~~ QUALITY

¥20 ......

·~--•--Wll!0>_,.-----~---~ ...... -·---•111t11#1!1!. IIIA-•.llll-llllllll7· ...

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I j NACATNINl lla&lonal Afthory CommSUN for Atrona11Uc1.

A MITIIOD l'OR DITSIUIININO CLOUD-DRDPLft l)IPINOSMl:llT ON IWl:PT 9.'DIGI. Robert O.

Dorldl and IUlllldD J. Bnua. Aprll IIU, atp.

dlqr1. (lCACA TN INl) Tb• pneral effect of wtas neep OIi cloud-4roplet tftledOl1H UOlll nepl "1ap of blp upect ratio morial at aablonlc .,... la dlectlllld. A mltllod of computllll droplet ln.leet011H about ,awed CJUadera ucl ... wtap .. preNntecl, ud Wutra• UH droplet tra1eetorle1 an computed. A metbod

of utendanc two-dtmeaalonal calculatlo111 of droplet

tmplnpmenl on DOnlwepl 1rinp to ••ept wtnp l•

preNnled. b la llbown Uw the 111t1n1 or lmplap• ment of cloud droplet• on an alrfoll nrface, the total rate of collecUon of water, and tbe local rate

of llnplnpment per IIAlt uea or airfoil 1111rface can

be fovnd for a 1wept wln, from two-cllmtnalonal data

for a non • wept wlnl, Tb• lmplnpmenl oa a IWllllt

wtn, la obta1lled from lmplnpment data for a ..,..

••• airfoil NCtloa which t • tbe Ame u tlle NCtlon in tbt normal plane of tbt • wept wtn, bJ calclllatlnl

all dlmenalonltH peramtttr • wttb re • ptct to now

condlUona in tile normal plane of Ole 1w1pt •lnl• NACA TN 3147 National Advlaory Committee for Aeronautic,.

IMPINGEMENT OF WATER DROPLETS ON AN ELLIPSOID WITH FINENESS RATIO 10 IN AXI· SYMMETRIC FLOW. Rinaldo J. Brwi and Robert G. Dortch, May 19H. 37p. diagra., tab. (NACA TN 3147) The pretence or radomea and ln1trument1 lbat are aenalllve to water mm, or ice formation. in tile noae section or all-weather aircraft and ml111lea neceul- tatea a k!lowledge or the droplet lmpinf,ement clul,· acteriatica of bodiea ol revolution, Bet'auae It II po11ible to approximate many of these bodies with an elhpaold of revolution, droplet traJet'torsea about an e\11paoid of revolution with a finene11 ratio of 10 were computed for inrompru1lble axiaymmetri<' air Uow.

Fron, the computed droplet traJf't't'>rif'I, the fol10•11.-1ng tmpln&ement characteriallc1 of the ellipsoid • urfac:e were obtainf'd and ue preaentE-d in term1 o( dlmen- 1lonle11 parameter,: (l) total rate of water lmpln&e• ment, (2) exter,t of droplet lmplnpment tone, and (3) local rate of water tmptncement. Theae tmpln&e• Dll'nl charactert1tlc, are compared briefly with Uloae for an elllpaold of revolution witb a {lneneH ratio of 5 reported in NACA TN 3099,

·- 4 • __ .... , ... __ ... ,,-~----- ~ ....

IIACATNI• NalioM1 Adtleo17 CoaalttN for At,..111,ca,

. IIIPINGIIISNT or WATU DIIOPLSTI ON AK

SLUPIOID WITI nNINUI RATIO I IN AXIIYII• IISTIIIC PIDfl. llolltrt 0. Dora, llllllldD J.

Bna and Jotan L. Ong. llarcll llH, IOp, dlqr1,, 11b. (NACATNI-) ftep,......ol radoae1111111 ~llla&ue NUltlft to water flllu or Ice formllklu Ill UMt - . aeetloa ol au • ...,.., aircraft 111111 mlNllu lllffNI• &atel a IIAowltclp ol tbt droplet lmplnpaeat Cllar•

MterlallCI ol llodlN ol n,ollllloL lleca .. • II

pou&blt to approldmalt mu, of &bell bodiea WU. u

'

elUpeold ol nwoluttall, dnplat tn,leetortee allolll u elllploid of rtYOlllltoa •WI • flAINN ratio of I .. ,.

computed for lDco..,....utlt ua.,mmetne a&r now.

Proa tilt computed droplet tra,eetorlea, Ult folknrllll implllp111ent cllaracterllttca ol tlae 11Upaoid nrface

were obtalr.td ud an prueattd La ttrma of dlm••·

81onleaa param•er•: Cl) tocal nit ol wattr laplllp• 1111nt, (2) Pltnt of droplet bnplftpmtnl IOM, (I) dletr&bution 'JI lmplftlinl water, and (f) local nte of water lmJlln&ement.

NACA TN 3153 National Advlaory Commllttt for Aeronautlca, VARIATION OF LOCAL LIQUID-WATER CONCEN• TRATJON ABOUT AN ILLIPSOm OF nNENEII RATIO 5 MOVING IN A DROPLET FIELD. Rabtrt G. Dorach and Rinaldo J, Bnn. JIily 1154, llp, dlacra., pbotoa., 2 &aba. (NACA TN 1153) Analy.e1 r.f calculated water-droplet traJectorln allow that the conctntrallon of llqUld water at ftrlou polnl1 about an elllpaold of rHolutlon morinc thl'Olllh a droplet field varlta conalclerably. Curve • of local conc1ntr1Uon factor H a fwicllon of apatlal poalUon are preaenttd In terma of dimenalonleaa parameters.

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otm C -CS<• •

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NACATNllH Nallonal AdYlaory COIDr IHN for Atronautk•.

' IMPINOSMINT OF WAHII DIIOPIZl'I ON NACA IIA004 AJIIPOH, AT I° ANGLI or ATTACK.

Rinaldo J. 8nn, Heltn M. Galla.,._, and Dorocbea I, Voll, July 1114. ftp. daaar•• (NACA TN UH) TIie lraJecto11tl of droplta. 1ft tht air flowtnl pUl Ill NACA IIA.004 airfoil at u anlle ol attack ol I° wre dettnnlned. 'ht amout oC water in dnplet form lallpiftllnl on Ult airfoil, Ult ana ol dNpltC ialpinp• men&, and l',t rate ol droplte llnplnpment ,-r WIit area on the alrfoll aurfact were calcuiliitd from Ult tnJectortee and preNntecl lo co.-r a tarp nnp oC fUlltt and atmoapheric condlUona. T11tN lsnptnp- ment cllancttrlltlc• are compared bnefiy wHII Ulole prtYloualJ reported for &lie nmt alrfoll at an ADIi• cg auack of 40.

48 .NACA TN 1410 NaUonal Adrieory CommlllH for Atronaullu.

VARIATION or LOCAL LIQUD>-WATEII CO~IN-

TRATION ABO\TI' AN ELLU 101D OP FINl:NUI RATIO 10 MOVING DI A DROPLET FIJ!LD. Rinaldo J. Brun and Robert O, Dorac:11. April ilH. Up.

dla,ra., photo,, lab. (NACA TN 1410) Tnjtttorle1 ol water droplet• about an tl.llpeold of rewlullon with a flnt11ta1 raUo of 10 (10 perctat &hick) in fillltt lhroup a droplet fttld wtrt computed with lht aid oC a dlfftrtnllal a,alptr. AnalJNa of tlltlt tnJecloriea lncllcalt tllal Ult local COliCN• tnUon of Uqwd water at ,arloua polnla about an tlllpeold nrlH conaldtnblJ and lllldtr ac>me coa- dlUona inay bt 1tnral Um•• th• fne-•ream con- centration. Cun,a of lllt local C1H1Ctfttratlon tactor u a function of epatlal poalUon were obtained and are preHnttd In lerma of dlmtnalonltH para111ttar1 that deacribe rupt and atmoapllerlc condlUona.

7 tt ,_

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· ~ Q # § &444 -.---~· - .......... - .... """- ..... ---- - c.c:;c • ,. ·---,~ --.. • - ...._ . -,.---....--.~ --.---.....- ~ ~.--.---- - ~--- .. •-• ••••""•--~--·----..~--i,!!!11-...!lllll••m- ..

NACATNHH NaUonal Ad•laOl'J CoaalllN lot Aeroaalllk•.

A DYS•TMCCJI TSCII~ JOI DNIIIIISNTAL• LY OBTAIMINO IMPINODIINT CIIARACTIIUl'J'ICI or ARBITIIAn IIODIU AMI> A Ml:TIIOD POii DITl:ltMININO Dll0PUT IIZI: DIITIDVl'IOIC, u.. ff. voa Clatla, no. .. r. Gelder 11111 ,mu.a a.

••1•t1, Jr. Marca 1911, '3p. daqre,, photoe., tu. (NACA TN IISI) . A c,e-cracer •~ llu.,... dHelapN lroa wMci.

Ill• droplat lmptnpmen& cllaracter&atk• ol bodl-. eu llf --•rmllled by eolorlaelrlC aalp&a. The lecll•

•uau• 11 appltcable lo ftr ....... , ... ).3 prvnded

Ille l111111idatJ of Ille air ,., ... cu be malnlaUIICI ..., uhanUon. A a1echod &a al&-> pnlNllled Wlltnllf lM drop~et a&u ~atrlthatlon ol lM WIP""11DI cloud NJ • determined bJ r•launa 1M upenmen1a1 &mp&np• 111•nt char1cterl1tlu of a boct, to the theortllc:al tra• Jeclory realalta (or tile Hme bodJ, NACATN 3$8'7

~o

NalJonal AdvllOl'Y CommUtN tor .uronautlc-.

IMPINGl?.IENT or WATER DROPLSTI ON A

SPHERE. Robert G. Dorac:b, Palll G. laper, and CharlH r. Kadow November 19$5, 29.P, d1afra., lab. (NACA TN Hl1) Droplet u .;.c!::i!"le1 about a ,a;phere ln Ideal fl11MI flow were calclllalt.., From the calc:uuled droplet traJectc.rlta, the droplet-lmplnsemn cllaracterla- tlc1 cf the lll)here wne determl-. llllpuipmnt data and 1q111tlona (or cletermlnlnl the collection el· flclency, tilt area, and tM dtltributlon of lmplAf• • mffll an prHent.d l.n terma of liimenatonl•u pa• rametera. The ran,, of Dish& and atmoapheric conchtlun1 covered ln the calculaUona waa extended con1lderably ~,onc1 the range covered by ~HYiO\llly reported calc11aUona lor th~ aphere.

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51 NACATNSIU

National AdYtlory CommlttM for AeroeautJca.

UIPINGEIIENT or WATER DROPLETS ON A RIC•

TAJIOULAR RALF BODY IN A TWO•DDIENIIONAL

DfCOIIPRB8SIBLE n.ow FlELD. wuuam Lew1a

ud IUuldo J. Brun. J'ebr11U'J llH. l'lp. dialr••• taba. (NACA TN H58) TraJec:torlff of water dropleta moVlnl In tbe ldu.l two-dlmenalonal flow field lbead of a body of nctaa• plar crou eectlon and lnflnSte dtent In tbe don- atrnm d1reetlon ba•e been calculaled bJ DINM of a dWerenU&l analyser. Data on collec:Uon efficilDCJ and diltrlbtmon of water llnpinpment are pnMlted.

NACA TN 3586 National Advlaory Committee for AeronauUca.

IMPINGEMENT OF WATER DROPLETS ON NACA 65.AOCM AIRFOD.. AT o" ANGLE OF ATTACK.

Rinaldo J. Brun and Durothea E. Vogt. November 1955. 28p. diagrs. (NACA TN 3586) The trajectories of droplets in the air flowlDg paat an NACA 65AOCM airfoil at an ~le of attack of 00 were determined. The amount of water In droplet form ilnpir.ging on the airfoil, the area of droplet impingement, and the rate of droplet impingement per unit area on the airfoil surface were calculated Irom the trajectories and presented to cover a large range of flight and atmospheric ct'JldlUona. These impingement characteriatics are compared briefly I" with those prevloualy reported for the same airfoil 0 •

at angles of attack of 4o and a

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__________ , ______ .....___

---.-...____ • < tt 2ffltitc «:IF:: ·t Cs,,._ g rtf.

S3 REPORT 1215 IMPINGEMENT 01' a.oUD DROPLETS ON A CYLINDER AND PROCEDURE FOR MEASURING UQUID-WATD CONTENT AND DROPLET SIZES IN SUPERCOOLED CLOUDS BY ROTATING MULTICYLINDD METHOD lly It . J. li • l •N, W. J,.:Wll J'. J. Pa: • &INI, n111J J. 8. 81UlA'1NI SUMMARY E,,abuitfon of 1M rotalifl! mtAltityliridtr ,n,tlwd fur t/u,, mecuurtm t of dropl,t-«iu dutril>-utiun, ,,.,1.,,,.,,-m«lian dropl,t rizt, a"'l /iquid-wattr contn,t in clouilx 11h11w,d tA11I 11mall 1111- ctrlai,uil11 in tl, 6axic ,lata tliminat tA, dixlinction 6,twt11 dijftrent dow.l tlmplrt..,,ize di. ~trib1tli111,., arul ar, a x,,i,rc, uf large err11r1J in th, drttrmit1atim1 of th, drupl,t Hiz,. f'alcwla- tiu1111 of th trajtrJ11n·,11 of dowl dr111,lrf11 i,i i· ru-11111pr xsibl, am/ eomprux-:bl, Jluw fi,IJ IS aruu.,ul a ryliml,r wn, p, rf11r111,J 1111 a muhanua/ analoy cm111tructtd f(lr tla, xtUtly uf th , trajttturi,x of tlruplt'fx :iround au1Jtly11amic b11di ,x. Ma11y data p11int1S wu, carrfu.lly ca/rulaltd in orJ r tu d,t rmi11, pr,cix,ly th, rat, of 1/r11pl,t i mpi'lly m ,11 "" tA, x-urfau 11.f a riyht t'irt'tllar culi,,J,,,._ Fr11111 ti, compute,/ ,lroplft traj,ct11ri r, ,, t/11 · f,,l/owi-11y impi11y l' - nu11t clwracltri, ,ti~ of th. r-yli111/u ·u.rjau u·, ·:·, 11btai11, , ,I am/ urt prex ,itnl 1 11 t,r111,'< of diui,11xiu,i/r ., ., J>aramt'lt'rx: (I) fut<1f raft' 11J u,atrr i11111i11y,mr,if, ( .2) uln,t ,~ ( droplt'f i111pi11!1t111,1tl wn,, ,11ul (S) lural ,/ i.,tributiun 11/ i111pinyi11y wat r ,111 cyli//tl,r 11u1:fac .

T/, ,, r11tatiny multirylimlrr 1111t/1ml for i11-:ffiyM drftrmi11ali11n nf litJ'! i tl- r: altr eont ,it, , 1r,.,i1 , t siz , a11tl dr11pl,t- .,i:e Ji11lributi111,

i II i ; 11y rl11ud ., ;., d r.srri b,-d . Tl,, tl,mry 11.f 11p rr ali1111. tl,r

11111111mf11 ., r 'luin-d. t/, ,. trr/11,i,,u, , 11.f 11bt,1i1, i 1,y dat11 ;,, _ tfiyl1t, 11111/ t/,-tu ,'/,./ 111,tlt ,11 / .s 11J r, /i-11!11fi1,y t/11 r, . ,11/f . ,, i11du,li11y ,,,.,. ,,_,_ ,.,,,.!/ clwrt., a111I t11b/,, . ,, 111 ·,, pr1xF 11fl'II . • 111 ,,vrl11ati1111 11/ t/11 Ill 11/t ,' ,·!l/ ;,,,1,,, 1111 '''"" i1,d111/, •. , ,,,, rtf,"' 1111 _fi nal ,., ,. ,11/t s 11_(

,1,..,,,/,1. tl,nt ,/,, ,,,,1 JrrF :, "111111l1 f,/ !I 1111 t/11 l'!/1 i 111/11 s 11,ff tr

, "<friki11y ti, 111 , "" ,, ,,, If 11 ., pr11ht1bl ,,,.,. ,,,., , ;,, .finnl r, ., 11/f,.. r1111 . -<r1/ by fl,,, i11l,n ·r 11I ;,, ." 11 . ~i tirit :; 11.f ti, ,, 11111/t,'l'yl ,',, ,t,,. 1111 · tl,111I .

NACA Rept. 1311 Nat!onal AdvlltOry CommlttH for Atronauuc1.

CLOUD-DROPLET INGESTION lN ENGINE INLETS WlTH INLET VELOCITY RAnOS or l.O AND O.'f.

Rinaldo J. Brw1 . 1957. U, 35p. dla,r • ., tab .

(NACA Rept. Ul'f. Supereede • TN 3593) Tbe patlll ol cloud droplet • into two enrtne lnleta ar1 calculated. The amount o( water ln droplet form lncuted by the Inlet • and the amovnl and dl • trlbuUon of water lmplnctn1 on Ule Inlet wall • are obtained from tbue droplet-trajec:lorJ calculation •. In bolll type • of lnlet a prolate etUpeold ol rnoluUon (10- percenl tt .ic k) rt: !' ·eMnt • either part or all ol U.

forebocf! at ~= center of an annutar lnlet to an enpae.

T~ c011fl111ratlon1 can al • o npre • ent a fu • elac• of an airplane wttb • Ide ram-ecoop Inlet •. The p•lnc pal difference between the two lnlet1 1tudled 11 that the Inlet alr HIOCIIJ ol one ll O.'f lb&t ul lbe other.

REPORT 1211 IMPINGDIINT OP a.ouD DllOPLITS ON A CYLINDlll AND PltOCIDIJU POI MIASUIUNG UQUID-WAl'D OONTINT AND DaOPLIT 8IZIS IN 8UPlltCOOLID a.GUDS BY ltOTATING MIJLTICYIJNDD MBTIIOD By ll. J. Hat•N, W. J.111w1a, 1•. J. Ps • &INB, w1d J. 8. 811MhNI SUMMARY

t

&ialution of tM rotating ,,..i,q,ntl,r MtlW /or lite ,,..,.,.,,,.,111 of drc,pltt..izt didrihtion, ttul••-nattlia,ulropl,t liu, at1d liquid-t11tWr ttmltflt in clow/11 Hltt?Dtd IAal «mall vn-

l

, ~rtai,&ti,11 in Ile 6o«ie data tliminat, tu di«tindfon lw'11wn ..

di.tftrent dotul dropl,l-.ize diNtributi11,,11 aml or, a IIOIUU 11/ ,.,.,,, UNlrfl in tu dttt.rmi,iati11t1 of tA, drc,pln «izt. ('alcula- hoftll u/ the trajttturit11 u/ duud dN1J,/rl11 in ifteamprtllllil>lr atHI

r.u,tapru,r:6/, Juw fitld11 around a ryti,ultr un p,rf,,nn,d "" a

,nttlianital analfHJ tor1Ntrud#d for tA, «tu,ly uf tA, lraj,eturir• 11/ drvpir't« ;uvu,ul urudpamic b,,di,11. Ma11y data point11 v,," car,Jully ca/culattd in orJ,r tu d,tm11i11, JH"CtlWl'I/ tu rat, ff/ Jn,pltt impi11!}f'mtnl un ti,, NUr/att ,~( a riyAI timdar cyt;,J,r.

Frmn t~ compulefl dropl,t traj,ctorir", ti,,- Jollowir,!I i1111ri11g,- m,nl tAaradtri11lu:11 u/ th, eylindrr svrfa~"' ttY,--t ubtai,u'fl am/ art prt«n1tnl i11 trnn« of ,limn~iu,i/rxx 11aramrtuH: (I) lulal ratr 11/ v-alrr i11111in!Jrm,11t, (t) ,.rtn,t t~( ,ln,pl,t i,,,pi11!}f'111n,t wn,, a11tl (S) lutal ,lilftribution of impi1,gi11y t.Valtr flll cyli111lrr 11ur.facr.

Tl,,, r,,tali11g multityli11tl,r 111,-t/w,I for i11:fliyl,t J,.trrminati,,r, o.f liq•! i,/ • ..,--attr t-0nlent, dr,,J,/rt 11izt, a,ul ,ln,pltt-xiu. dixtribulim, ·i11 i611u t'l111ul" ;." ,/r."tribrtl. Th, tlm11-y •~f t1Jwrotim,, tit, UJIJHll'Otu" rf11uir,-d, tl,.r 1,-tl,11i11u,- ,~( obtt1i11i11tJ ,lat,, i11 :,li!lhl, 11ml ,1,-t,,if,-,/ mttlt,,,/,. of talrult1ti11t/ ti,,, '''"'"'"•• i1,clu,li11y 11,-rrN1tt11·y tlwrf,. am/ t,.6/,-N, ,.,,, ,,,.,,"""'"''· .-111 rmluati1111 of t/11 11,ullir!Jli11du 1t1t·ll111tl i11du1/1·,'( flu- ,_ff,·d 1111 .fi11al ,.,,,cuff,. o.f ,1, . .,,,1,-1." tl,at ,lo '"'' Jr,,-z,, r111111,l,-t,-/y "" 1111· rylimln" ,1.fta

Nt,·iki,,u ,,.,,,,,, "·" ""'" "" ,,,.,"1u6J, ,,,-,-m·-" ;,, _fi,,,,, ,.,.""''" m"-""''

l>!J tl,r i11/1nt11I i""""·"iliril:J ,~( tl,r 11111/tir!lli11tl1·1· 111,·tl,111/.

• NACA Rept. 1111 National Advlaol'J CommlttN for Aeronauuca.

CLOUD-DROPLET INGESTIOfol IN ENGINE INLETS WITH INLET VILOCITYRATIOS OF 1.0 AND 0.1.

• Rinaldo J. Bna. lts1. U, ISp. dllcn., tab.

(NACA Rept. 1311. SuperaedH TN 1591) The patlla ol cloud dropleta bllo two en,lnt lnleta an calculated. The amount ol water bl droplet fora lnplted bJ tlle Ulleta and the amount and diatrlbullon

of water lmplaplls on tlle Inlet -n• are GbtalMd

from theN drop\et-trajector, calculattone. In baUl typee ol bllet a prolate e\Upaald of rnoluU• (10- percenl U..CII) n!'-nent• either put or all ol U.

fonbcld! at !!!: c•t•r ol • auular Inlet to u ......_ T~ conftpntlona CU\ aleo repreNat a fuselap of an alrplane wttll .,. ram -ec:oop lllleta. TIie prlllcipal difference between tlle two ln\lta atudled la tllat tbe Inlet au welocltJ of one la o.T tbat ul tbe otber.

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·:: :a it NACA TN Uta Natloaal AclYtaorJ Commlttee for Aeraulltlca.

DROPLn DIPINGEIIENT AND INOEfflOK n

SUPERSONIC NOSI INLET IN SUB80NIC TUNNKL CONDfflONS. Tbomu I'. Gelder. May 1958. Sip.

dlaet't,, pbotoa. (llACA TN '218) Tbe aa:ount of water ill cloud draplet form lftttltH by a fwl•acale aupenaatc noae Inlet w1tll conical centar bodJ ,ru meuund. Local aacl total flier lmptn11meat ntaa on tbe cowl and cnteNIOCIJ Ml'• : face• were alao obtaiMd. All meuuemnta wen made with a d,--tracer tec:lmlqae. IDJet up1 of

attack of 00 and ,.ao, droplat dlameten from l1 to

•

20 mlcrona, aa.t ratloa of Inlet to tne-atream wloc• itJ from 0.4 to 1.8 were at..sled. lleU1&nmnta were confined to a free-atream llacb Dl&lllber of 0.231 and are extendable to OIMr aubaonlc apeeda bf dlmenslonleaa lmplogement puametera.

NACA TN 38311 National #,dvlaorJ Commit'. ?e for Aeronautlc1.

EXPERIMENTAL DROPLET IMPINGEMENT 0K SEVERAL TWO-DIMENSIONAL AIRFOILS WITH THICKNESS RATIOl!i OF 6 TO 16 PERCENT.

Thoma • F. Gelder, William ff. Smyer•, Jr., and Uwe von Glahn. De..--ember 11156. 1'7p. dlagra., phnt:JIJ., tab •. (NACA TN 38311) The raie and area of cloud droplet lmptnpment 011 al'veral two-dlmenalonal • wept and 11111,rept alrfolla were obt.11.ned experimentally In the NACA Lewia king tunnel with a dye-tracer technique. Airfoil

thirkneaa ratlo • of e to 16 percent, anglea ol attack

from o to 1Zo, and chord 1i&e • from U to Iii lncbea were lncluded In the atudy. The re • ulta are pre- sented In the form cl dimenalonleu impingement pa- rameters In order to cover a wide range of flilbt ancl almuspherlc conditi~.

r-,m¥4 .,. -~·~.-!:.: 54 :;u:,4144i!wL.--·••!:jiil>_ "r,", ____ c;.;;;...-------------=..;;;i-m.;=;;;;:.:,i__,....,. __ ._.. _____ ~"'-"111111•

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NACA TN 37'0

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National Advisory Commlttff for Aer011&11tlca.

UIPINGIIIENT or DROPLl:T8 IN '°° ELBOWI

WITH POTENTIAL FLOW. Paul T. Bawr, hlll G.

I laper, Uld CbarlN r. Kadow. October 1111.

L

Mp. diqra., tabe. (NACA TN 3110) k

f

Ttaeoreucal tnJectorlea were cletermlMd for dropleta • ln alr fiowlnl tbrOUlb 900 elbon. The elbon were

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,, eatabUabecl by NltctUII u nlla ol eacb elbow two

atnamU..a Of a two-cllmenalanal now field prodlaced

by a complex potenUal function. The .. elbon are aultable for u .. ln alrcraft air-Inlet duct&. Droplet lmpinpment data are preaenlld in term& ol d1aam-

~'

alonleaa parameter • atonc wltb emplrlcal equau.&

•·

ao that the reaulta can be aprlled ower • wide nap · of condltlou and elbow alzea. A comparlaon ol lbe

eoo elbow wltb previous calculationa for a comparable

90° elbow lndicated that lhe l.mplnpment cbaracler- iatica of the two elbowa are very aimilar.

NACA 'IN•on

National Advlaory Committee for Aermautlca.

EXPERIMENTAL DROPLET IIIPINGEIIENT ON FOUR BODIES OF REVOLUTION. Jamff P. Lftia and Robert 8. RugerL n.c.mber 1951. elp.

diap'a. , pbotoe. (NACA TN •OIi) The nte and ara al. cloud droplet lmplA,emelll ca four bodies Of revolution were obtained experi- mentally ln lbe NACA Lewla lcllll twmel. Spbe.,.., ell1pao1dal forebodiea ol fiaeDeN ratioe ol J.5 ud 3.0, and a conical fonbody ol 300 included Ullle 0 ,

were atud1ed at &111lea ol attack ol 00 to e rota-

tional &peed& up to llOO rpm, and an atrapeed al 15? knota. Tbe reaulta are preaented in the form ol dimenaionleH impinpmut parameter• la order to cover a wide raap ol flipl and atmoapberlc cond1Uona.

....... i, fit dm ......... ntftt tt':C,t c tet:5lb O M ,. .

,;42 p; .urn+ ;

a_

• -1 .... Q4JQ¢14-CP)J$$£!1 Q@ Ai. Ott &

I aμ PM!i.

IS -~-- ~J F ~TZTRW SACA,,,. 4031

S9

N~.llun.-.1 Adv!1ory c.,mmlttH for Aeron:uallu.

1MPINGl...4ENT OF CLOUD DROPLETS Otl M.1- PERCENT-THICK JOUICOWSKI AIRFOIL ~T ZERO

ANGLE OF ATTACK AND DISCUSSION or liSI AB

CLOUD MEASURING INSTRUMENT IN DYE-TRAC&ll TECHNIQUE. R. J. Bnan :ind Dorothea&. Vop, St'plt'mt>.r 195'1. Hp. d1.11ra., t.ibl, (NAC A TN 4035) The tr::jKtorln o( droplet, tr, Ule ;alr fiowtag paat a M.5-perc•nt-th!rk JO\lkowakl airloU at aero ansl• ol lltC..rk were cletermlnt'd. The amount ol •~ter ln droplet form lmp,ngina on the alrtoll, the area ol droplet ilnpingt'ment, .ind the rate ol droplet implnp- mt'nt per unit .are .. on the airfoil 1urface were calCll- lated from the tr .. jtttorlH ;.nd cover a larp ranp of flight .ind .. tmosphnic conditlona. With the de- t.ail•d :mp:ngement inform .. uon available, the H.5- pcl'<'ent-thick Joultowski ran aerve the dual purpoee of use a11 the prinr :pal element in lnatrumenta for making meaaurementa ln clouda and of• ba1ic ahape for eatim:itlng impingement on a thick atreamli.ned body.

60 NACA RM 1:56111

National AdvlaorJ Committee for Aerona11Uca.

\JSE OF TRUNCATEJ> FLAPPED AIRFOILS FOR IMPINGEMENT AND ICING TESTS OF FULL-SCALE LEADINO-EDGE SECTtONS. Uwe H. YOll Glalln.

July lllH. 29p. diagr1 , photos., taba.

(NACA RM E56Ell) Experimental 1tudie1 nre made with an NACA 151 -212 aldoil NCUca truncated at the 30- aad 50- pe,:-cent-chord 1tatl01111 and equtpped witll I tratlilll- . edce flap. When UM truncated airfoil• nre com- pared with the full-chord airfolla, the ••loclty dla- tributlon and the impingement characterlatlca were aimilu •Ith the flap properly deflected, but were altered 1ub1tanua111 wltbout nap deflec:t1011. Uae of flapped truncated airfolll permit• impingement and icina 1t11diea in icinJ tunnel• to be conducted with full-1cale leadinC-edce HCtioM over a ,realer rap ol coodiUou than prevtoualy pOllaibtt.

_____ ,_....,...,._ .... _ !SOS..,.L!~.-~. -~-.::".- .:-::a;;;,·oo..16iu __ __,,..,.. • .._,.....,._......;,,.. ..:..;.,;;_..,..i;y""~----..._ ...-z:: r ,m

Propeller Icina Protection NACA TECHNICAL NOTE 1178 A FLIGHT INVESTIGATION OF THE THERMAL PERFORMANCE OF AN AIR-HEATED PROPELLER John F. Darsow and James Selna SUMMARY Observations were made during flight in natural-icing conditions and by the collection of thermal data on the propeller during tli~ht in clear air and in clouds at temperatures abo·,e freezing. The propeller was equipped with standard hollow steel blades which were altered to permit heated air to enter the blade cavities at the propeller hub and to leave the cavities at the blade tips. The distribution or air flow inside the blades was not controlled.

1be ubservations in natural-icing conditions together with the ther- m.al. test data indicate that little or no protection to the leading-edge region of the propeller blades would result during flight in severe natural-icing conditions. In natural-icing conditions only light-icing conditions were encountered; however, ice accretions formed on the leading edges or the blades in the region of blade stations 30 to 40. The clear air and cloud tests showed the propeller blades to be inefficient heat ex- changers in that more heat energy was discharged in the air flow leaving the propeller than was dissipated through the propeller-blade surfaces.

The measured blade-surface temperatures indicated that inadequate heating was provided to the leading-edge region or the propell er and snow the need of providing neans to increase the heat flow through the leading-edge re- gion or the b.ades.

IoiDS u4 De-IoiDI or a 1ropell . .- wlth Imer-.1 m.eotrlo lla4• l•tere BJ .i .... 1. i..1 • an4 lanr4. c. sinna, Jr.

IACl B lo. 1691 AQSat, 1968 lb~ n.-101111 etteo1ll'Yon1 •• or 1at.rml eleotrlo

propeU.--'blaAe IINt.- - • u~ a11 '9o lolDC al

1llo o,aa\1111 OOll41'1oaa wt\la IINt applle4 oont1aa- o~ u4 Q'oll~, u4 tu ftllllrecl b9at-oa u4 cvol• ts.. • an uon.

CJMmlwlN •neat of loizll waa gN&t• tban tat OOTvel b7 'bla4e llea1ler1. Met•t• &e-1o1DI 1D ll•W.

ar • wlth oont1D.1)0u IINtllll wa1 o'bt&lml wtt!l ,onr •••U&bl• lnat aulaa pow• input ot 1250 •tt • ,er bla4•,,.. lmutttotent tor o,olto te-101111. Sartaoe t.perature-rlH rat•• of 0.2° to 0.1° ~ ,er • eooD4 were obtalMCl u4 al:&19a oooliJlf'> per1o4 tor o,11o ... 101111 - • &JP1"0Zlll&tel7 2i tllle • tM IINtiD& perlo4.

De-Ic!Dg Etrect1Tene • e ot hterneJ. 11.ectric !eater• tor Propeller :BlAdea.

BJ Jamee P. Levis MCA TN No. 1520 Februar1 1948 Abstract Icing protection proTided by exten1al ruober-clad propeller blade beatere at several icing, beatiDB, and propeller opera t 1.no cond1 tiona has been determined.

Etfecta or propeller speed, ambient-air tempeirature, liquid va t e~ concentration, beat1Jl8 power density, dura- tion of he.atins, &Dd total c,cle time on power require- ments and 11e-1c1DS pertormance were 1nTtat1pted.

Power dene1t1ee or 4~ to 10 vatte per equare inch

veN required. tor cyclic cte-101.ng v1 tb best ohQrdviee d11tribution approach1Il8 1Jni.torm1ty. Heating t1JN1 or a pproximatel7 2, eeeonda veN req_\lired Yitb ratio of best-on to total c1cle tiJDo of 1:, giviag beet reea i t ••

Hean rate or rile of beater temperature ot approX111&tel1

1.1 ° 1 per eecond vae obtained.

GE IS O OR QUALITY

64 An Kleotr1o Thrut Meter Su1 table for r1.1pt IlnN• t1pt1on ot Propeller•.

11 Porter J. Pvki.Da an4 Mortou B. Milleuon llACA 111 lo. 6017 Nay 19'9 Abstr-aot A l.1gbtveiabt 1nstrument tbat utilizes re11 • tance- v1re electric • train gages to measure propeller-aha1't thruat baa been developed. A vind-twmel 1meatigat1on on a propeller installed on a aiDSle-engine purauit airplane ahoved that the instrument save a reliable 1nd1cat1on at propelbr-ahatt thrust to an accurac1 ot ~ percent v1tb1n 1ta calibrated rans•• 110 attmpt va • made to determine the relation at 1D41cated abaft thrust to net propeller thrust.

Innat1sat1on ot Brtectivenea • of Air-Beating a Bollov Steel Propeller tor Protection apinat Io1QS. I - Unpartitioned Propeller Bladea.

B1 Donald R. !t.llholland acd Porter J. Perkina BACA Tlf lo. 1586 Ma7 l9j8 Ab • tract An ioina 1nn • t1gat1cm ot an air-heated hollow • teel propeller with blade • ra41all7 part1t10D84 at 25-percent ohorcl vu oaaduot.4 1D the DCA Clevelan4 icinc NH&roh twmel.

Beeult • • hoved that at 850 ria a heatina rate of 7000 Btu per hour per bla4e pronde4 adequte 1o1Da protect1cm at 23° r but not u low u 150 r.

Surface t•peratUN • 1n41oate4 eati • taotor, ~or4- v1 • e 41 • tr1but1cm. Th• blade heat-exchanger etteo- tl•en••• va • found to be 77 percent.

~DICAL llOrl IO. 1587 DiiBtI'1ATIOI o, ifHXitlfWWW or AIR-DAflJIC A IOLlDII 8'1'DL PROPILtD JOlt ~IOI AallllST ICim II - 50-PDCiif PAITITIOBD BLAD!8 J.r Port.el" J. Pert1n1 u4 Donalt J. Nulllollu4 Th• 1cin6 protect1oc attor4e4 an internal air-heated propeller 'blade b7 n.cUal part!t1oc1.Dg at 50-peroent ohor4 to CODtine the heated air to the tontard halt ot the bla4• •• 4etera1Ded 1D the MCA CleTelan4 1c1J:lg NH&rch tunnel. A 110d1.t1e4 pro4uct1on-model bollov it.eel p:ropeller W.I UNd tor the 1D•••t1pt1oc. Teapen.tUNI ot the bl.&4• 1urtaoe1 tor Hnn.l heatl.Dg rate, were •a1ured UD4er •ar1ou1 tunnel 1cina cond1t1cme. Photogaphic obHnat1ona ot 1oe tonat1cm1 an blade 1urt'aoe1 and blade heat-ezohanaer ettect1nne11 WN obtalm4.

With SO-percent part1t1on1ns ot the bla4e1, adequate 1cins pro- tecticm at 1050 rpD w.1 obtained vith a heatins rate ot 26 000 Btu per hour per blade at the blade ehank u11Dg an air temperature ot ,oo<> J' v1th a t'lov rate ot 280 poun41 per hour per blade, vh1ch 11 one-th1r4 le11 heat than va, found nece11&r7 tor 11a.1lar ice pro- tect101l v1th anpartit1ane4 bla4ee. The chordv1H 411tribut1on ot tu applied heat, a1 4etendne4 b7 1urt'ace temperatUN •a1ure1119nt1, va • c0D114ered unati • tactor, v1th 11Wch or the heat 41111pate4 vell back ot the leadins edge. Bea.t-exchans•r et'tecthene11 ot approzi- •tel.7 56 percent al10 indicated poor ut1lhatton or aT&ilabl• heat.

'l'h11 ettectinne11 va1, however, 9 percent greater than that obtained trom unpartitioned blade ••

ln•••t1•t1cm ot stfeot1~•• ot A1r- .. at1Jal a lollov Steel Propeller tor Proteot1CD acatA • t Io1D&.

Ill• 25-Peroent Part1t1cme4 lla4e •

17 Daaal4 I. Nulllollan4 IID4 Porter J. PerktAA.

IACA '1'I lo. 1588

11111e,e

Ab • traot All 1o1q 1ATe • t1.t1m ot an air•hNW hollClllr • tHl propeller v1 t.b bla4•• n41w.17 pu-t1 tlaMI at ?5-percmt ohar4 vu OCD4uote4 1A the MCA CleTelu4 1C1.Da NH&l"Gh tUDUl.

Benlt • ahovecl tbat at 850 rpa a hMtiDa rate ot 7000 Bt11 per hour per bla4• proT14e4 a491ute 1c1Da proteot1m at 23°., but DOt u lClllr u 150 -,.

Surtaoe tapen.t1&n1 1D41oate4 • at1 • t&etor7 ohor4• v1H 41 • t.r1bu\1CD. 'l'h• bla4• heat-•xcbMcer •tt•o- t1•m••• vaa tound to be 77 percent.

NACA TECHNICAL NOTE 1494 A METHOD FOR ESTIMATING HEAT REQUIREMENTS FOR ICE PREVENTION ON GAS-HEATED HOLLOW PROPELLER BLADES V. H. Gray and R. G. Campbell SUMMARY The propeller blade is analytically divided into a number of short radial segments, successively treated as separate h~at exc: angers. Ex- pressions for the total external and internal heat transfer are combined to determine the surface temperatures of each segment. The thermodynamic steady-flow equation is given for the internal gas-flov process and ex- pressions are obtained for the radial variations of gas temperature and pressure within the blade. For a given initial gas temperature in th blade shank ~avity, the minimum gas flow is determined, vhich will pro- vide surface ~ emperatures of at least 32° F everywhere on the heated portion of the blade. An expression for the required heat-source i n r, ,1t .

to f,he ga:; is included and a formula is given for calculating the r e- quired blade-ti nozzle ar a.

NACATNIIII National Adnaory CommlUN lor Aeroautlce.

AN INVUniATIOlf UTILIZINQ AN IUCTIUCAL

ANALOGUI or CYCLIC DI-ICING or A 1101.LOW

IITSIL PROHLL&ll WITH AN IXTlllNAL Bl.ADI ao1. Carr 8. NNI, Jr. Dec .. ber ltll. Hp.

cil • lr •., pbotoe . , S tabe . (N .. CA TN UII)

A •IIIIJ ol U.. lleat ,.iremeeta lor c,ellc ••lclll

ol llollow etNl propeller • Rtttd wllll eat1nal blade

llloee, 11tlli&1al u electrical ualope, MOWN llow euro requlrem . ••• COIIJd be dec:reuecl 117 cllul•• la 1111 method ol operatloa of 1&1at&as llloee ud lbl'OUlh proper bladt-llloe dteiln, •'ri111• Ill total •Ml'ff In Ille order of to percent WOl&ld bl poulbl1 lll •ch CUI . IM"IJ reqvtr1m111l1 Wlrl ehown lo lncrtut wtlh dtcr ... 1111 Uqllld-water contelll and air temperature .

•

NACATN 3025 National Adneory Commllln for AtronauUce.

AN lNVEITIGATION trrlUZlNO AN 11.ECTRICAL

ANALOGUE or CYCUC DE-ICING OF HOLLDW

STEEL PROPILLERI 'Wff'H Dn'!tRNAL 11.ECTRIC HEATERS. Carr B. NNl , Jr . October 1113 . Up .

diaJrt., photo., 3 tabe. (NACA TN SOU) An analytical etlldy, utlll&IIIJ an lltclrlcal lnalOI\II, or the htal rtquir1mtnt1 ror cyclic d, 1-lclnJ or hollow elHI propelltrl UUtd With two ,,,.. or lnltr-1 1lectrtc htaltrl lhowtd Ult lmpracllcablWJ of UIIIJ an lnltrnal tubular heater, and lllllltrattd lilt · advanlQH of tmploylnJ an lnltrnal 11101-tn,e bNltr lo clillrlbutt \ht heat mort l'HNJ lo lhl blade 111r- fac1 . The Importance or mlnlmlllnc the thermal IBtrtla of the 1y1tem wu demonatrattd, and Ult ::nalftltudt or rtductlou In tht total entrff reqvtre- ment mad, poaalblt lhroUJh redllCIIOU In hllllnJ period wu lndlcattd .

71 KATI<lW. ADVISCIIT CCMa'l'lU J<l' ADCIIAUTICS ti'CDICAL WOl'I 2212 TD ~T Cll ICI JCIINATICIIS CII PROPILIJ:R PIRJ'CIOWl:I BJ Carr B. Neel, Jr., aD4 Loren G. Jript St1114ART • M•1urement1 of propeller etticienc7 loe • due to ice formation are • upplemented b7 an anslysi1 to e1tabli1h the •gnitude of efticieney l011e1 to be anticipated. during tlipt in icina conUtiOZll. T".ne mea1w-e- •nt1 vere ade durina flight in natural icing cODditicma; vheree.1 the anal71il conailted or an inveotip.tioa of cbange1 in blad~ection aer~ dynamic cbaracteristic • cauaec,. by ice formation and the retulting pr~ peller efficiency cballlea. Agreement in the order of •gni tude of ert1- cienc7 lo11ee to be ezpected is obtained between mee.1ured. and analytical result •• The re • ul'ta indicate tbat, in general, efficiency lo11ea can be ezpecte,ci to be le11 t.ban 10 percent; vherea • azillrllm loa • H, vhich will be encountered only rarely, may be aa high aa 1, or 20 percent.

Jeported. lo11es larger tban 1, or 20 percent, baaed cm red.ucticma in

airplane performance, probably are ~.ue to ice accretiona on other part, of the airplane.

Blad~lement theor,- 1a ,wed in the analytical treatment, and cal- c'61.ationa are mde to 1hov the degree to vhich the aerodynamic cbarac- teri1tlc1 of a blade aection must be altered to produce ftri0u.t propeller

efficiency lo11e1. ~e effect, of ice accretion, on a1rfoil • ectio~

~baracteri1tic1 at aubcritical speeds and their influence on drag- di~erg~nce M~ch number are esamined, and the attend.ant mazimum efficiency lo11es are COl'lputed. The effect or kinetic beati~ on the rad1al extent or ice formtion 11 considered, and it1 influenc~ on required length of blade beBtin& 1b061 11 di1cua1ed. It 11 dem"118trated hov the efficiency loH reaulting from an icing encounter ii influenced by the deciliona of the pilot in adjusting the engine and propeller ccmtr~l,.

Induction Sy1t .. lcin& Protectiog TICDI-:AL Jar& 10. 1790 DVJBTI(M.l?J:01 or ICDG CIWtACTDISTICS Of nPICAI.

LICm'-AIRPLAII DOID DmJCTIOI anms

11 V11lar4 D. Cole • Tbe 1c1na cbaracteri • t1c1 ct tvo tn,ical light-airplane engine 1n4uctlon •1•teu vere iDYe • tigated uaing the carburetor • and man1- tol4• of •rwt1m • 1n the hcr1epow1r ranee• trcm 65 to e.c; an1 165 to 185. The ID&ller 111tem cona1 • ted ot a tloat-type oarbur1tcr vith an unheated manifold and th• la:rser ayat• conai • ted or a 1ingle- barrel preaaure-type carburetor v1th an oil-Jacketed manifold.

Carburetor-air temperature and hum141ty ltmlt• ot T1 • 1ble an~ nrioua icing ven detltrmined tor Tar1oua ena,ne power ccn4iticna.

8•••ral.-tho41 or achie•1na ice-tree iniuct1on • y • teu are 411- cuaaed alons vith e1t1tiste1 or • urrace beatir,1 requ1reunt • or the T&r1ou.a 1nduct1on-•1•tem componant1.

A atudy va • al • o made of' the ic1ag cl:arac er11tic1 or a typical Ugbt-atrplane air • coop vi th an expoeed t1lte~ • and a modU'ted • 7atem that proTtded a normal nm inlf't v1th the tilter lecated 111 a po11t1on to induce inertia • eparation or the tree vat•r f'rem the cbarg• a1r.

Th• principle or opt i .ration or float-type carburetor• 1a prove'!

to nke the: ir.herentl,y mo e euaceptible to icing at the throttle plate than preuure-type earburetor1. Tho re • 'Jlh 1n. 11cahd thst proper Jacket1Jli and beating or all put • erpoaed to the f'uel 1pn,y can ut11ractori!, reduce or eliminate 1cin, in the float-type carbure._or an4 the manifold.. PreHi.r•-t~ carburetor• can be J)rOtectei trom ••riou.a icing by proper location of the tuel-41 • ch.ve• noiile cnm- binK with • utt&ble application of' beat to critical part,.

ICING•PIOTICTION HQUIRL\1£NTH roa UCIPIOCATING-~CINE

INDfCTION llbTl:)121 11, W11.u11• D. cu .... , v ..... a. llul.LIN, .... , l>uu ... ,,. ~ht&.IIUl,l,AH IUMMAH

lllq,ilr lite J,f'ftfl,,,,.,,., ti} mfllim1 i,,,-Jrrr ft,,1_,,.,1,ri•1

.,._., Ck tlliJ,aJll'lflll ti« uJ abtr11t1t, a..J lwt,J,J~ir i,.,dfl,.,

••J 1M IMlf .J alcolw,I Jo, ,..,,.,,.,., J,.;c;,.,,, i,;,.,, 11/ airr"4/t-

,-,i11, i..J9'dt0fl ...... Ma.,;.,.,. ,,,...,,.. ,,..,.,;,,,:;.,,.,, MN 6cn •• to fllttq •• t. NMNl all,-,.,. uj IAi• ,,;,.,, """""'· l'nn,a ..,., it1•fllif"lir11•, ui1,riu1t11 Jo, •Jt o,w,..

,;,,,. a..J Jor ,l,aif,a u/ ,.,. i,.Jw,;,,,. ,.,,.,,,,.. 4caN w,,. ,...,._

li.J&MI.

Tlw ,,..,,1,. arc o61aiflhl /ru11t ,.,,,_,.,,., ,,.riratifll'lio1t• uj

CfU'6wrlur-nJllrdaMflC!r r111116i • al i """, .,,; 11 d -I,.,." ,I i II r,,J i ,,.,.

lw11• uj •ir KOuJH, Mvllicyli11,/,r...,11gi11e "'"''""• 1111,I JlitJltt i11w.tifll,lW11•. l'luuaduialir.4 uj ti,, tArrr .fw-111• uj ir.f', i1H11dd, llaruttli,,11, .,.,/ J-,,,1 1ou11CJN1iu11, nre -,.,,,/jr,/. 1'1,, rj(rrl11 u.f wttrral judur• 011 ll&t iciflll r.1H,rwt,ri-tir11 torrr 11/,w llltM/ir,/ 1111J i11d.,,,/rJ (/) "'"'"J.Arrit c:u11Jitiu111t (.t) r1111i11r 11111/ tiir-,crwp

ru1,J.1111ruliu11• 1 ilfd,,Ji,,u li,,,.,-11ir1,la11, •N"''""'• (~) lf/J" uj

.f~I t1«J, a,.J (4) op,rali"fl ruri1161,11 1 url, 11a JMill'lrr NmlitiuH, .,., uj • ,1101,ijulJ 1•rt1U1Vn rrv,,lolur, H1iJ11,rr arlli11!/, curhurrlur lwut, a,ul .,,,,,,11/rol.ol i11j,cl w11. I 11 11d,I it iu1,, ic,1',lrrl iu1t t11tll1uJ• .,,,,, i,er,llligut,J a11cl ,,,,,J.uc,• uj ,,,,,.,,.,.,;,.,, u11J rt• ,,,u,,i1111 i,ulwtioa-qllt1111 iu or, •t.Ji,J. Jlrcu11111er11J11tiu11• are 11imt for d,.ign a,,J UJ•Utllio11 tv&tl. rtt}Gtd tu i11dt1diu,,- •r-'•• ici,. 1.

MAC.A JIM SUD>'I Natloul Adftaory CcemtttN for AermallllkL IMVEITJGAffClil or ilRODYNAMIC AND ICING CBAIIACTl:IUITICI OP A FLUIII ALTERNATS- DILET DfDUCTD-ITITIM ADI ICOOP. laan P.

Lnta. ll&IJ HU. 4Zp. dlap'a., plaokla. (MAC.A JIM EUl:07) AD me~ al 1M .. ....,_le ud kll!S mru-- tertattu al a hll-acal• a..eu. • ., • .,. au---, aueablf lacor1lontllll a Dula-tnie a1tffale lalat wa1 ~ la die MAC.A IAwt • ldlls rneudl ._L TM a.-•tpttoe Wlll ..... O'Nr I :up al mau-w-Dow l'IUol, aa,ln al alaek, ~.

air ...,.,..,..,, U..W-water ~ 1M d,nplet .tuL TM nm lalat Pft pad pre • -n l"HOffry la batll cl•r alr ud lea., 1M .,.,Id bloctillc s U.

Clrtl'U'llor Kl .. OCCIArnd la k&III. TM alle,_..

lallt "'Ml poor pndU'e '"°"" ID llo&II clear alr

Ud ldlls, 1M IIO Nrtou KN• kll!S 11111 olulMll.

flw laN • t~U. Wllldld tM .. al prelleat alr alou ud ' A comblMUOll w1tll nm- ud allerM11 • lalet air .

.,

Turbine-Type Enaine and Inlet Icing Studies 75 Natural Ic1ne of an Ax1&1.-Flov 'l'urboJet IDsine 1n Fli@ht for a Sinsle lcine Condition.

By Loren W. Acker NACA RM No. E&Ola August 12, 1948 Abstract A tli@ht investi@B,tion in natural icins conditions was conducted to determine the effect of ice formations on performance of axial-flow turbojet engines. Results are presented for a flight in which liquid-water content varied from 0.077 to o.490 gram per cubic meter.

During(,() minutes in icing, tail-pipe temperature increased from 865° to 965° F and the Jet thrust decrea3ed from 1950 to 1700 pounJ..s. The engine was satisfactorily accelerated to take-off power near the end of the icing period.

Pre) 1m1MJ"':!" Results of Natural Icine ot an Axial.- Flow Turbojet Engine.

By Loren W. Acker NACA RM No. E8Cl8 August 1918 Abstract A flight 1mest1sation 1n natural icine conditions vas conducted to determine effect of ice fanmtiOIMI on pertonance of an axieJ.-nov turboJet engh,e.

Resul ta are presented tor a tl.isht in vhich the icins rate Taried tram 5.1 to 2.1 inchee per hour.

Dm-ine 45 111.nutes 1n icine, tall-pipe temperature increased f'rcm 761° to 1065° rand jet thrust decreased f'rca 1234 to 910 pound.a. Ice peuetrated to the eecond- staee stator bl.adee.

Icing Characteri1tic1 and Anti-Iciq Beat Requirement • tor Bollov and Internally Mo4U'1e4 Gaa-Baate4 Inlet Ouide Vane,.

By Vernon B. Gra7 and Dian T. Bowden BACA RM 150108 December 1950 Abstract Gas temperatures and flow rates required tor anti- ic!ng a tvo-d .imens i onal cascade of turbojet inlet guide vaneB vere determined for hollow and internally modified vanes. The pressure losses caused by icing on unheated guide vanes were also determined.

Less heat vas required tor anti-icing internally modified blades than for the hollow blades. Pressure los,es across the cascade vere greater at an inlet tem p erature of 22° F than at o° F because of the characteristic shapes of ice deposits at the tvo temperatures.

NACA TN 3UT National AdYl1orJ Commlttff for Aeronautic •.

INVESTIGATION or KEAT TRANSFER FROM A STATIONARY AND ROTATING ELLIPIOIDAL FORS- BODY or FINE ES8 RATIO, . Jam- • P. IAwlll ud Robert 8. R11111rl . Noftmblr llH. •ep . cliap'e., pbot..,,, tabe . (NACA TN 313'7) bp1rlm1atal CClllftCtlft b•t truafer w 1> • obta1Nd for L.J0-lllcb-d.lameter for•bodJ for alral)ffde up to HO knot •, rotational •Pffd • up to UOO rpm, &111I•• 0 , 0 , '-' attack ol 00, , and e ud botJI unl!orm 1urfac• temperature and unUorm lnput but dtneltJ . Tb1 r11wt1 apN ••II with Uaeor1t1cal pr1dlct1au . s,.

fect1 ol rotation Wlrl lllllpUlcant, ud 1fl1Cll ol anal• ol attack onlJ minor. Tranattlca from laminar to turbulent heat traufer nrled O'l\r a R1,nolde a11111blr ranp ol 0.1 • tol to I• lo • . Limited tru• 1l1nt b1atlne data Indicated that tbe c:llup ol eurfac1 t1mp1ratur1 wll!I tlm1 followed u IJlpCIHIIUal relatloa .

NACA TN '8H NaUoul Adneol'J Committee for Ael'GllaU&lea • . INVISTIQAffON or DAT TRANSFER 111011 A STATIONARY AND ROTATINQ CONICAL FOllS- BODY. Robert I . R111Prl aad laau P. Lffla .

October llH. SClp. cllacr•·• fMIO,, lab.

(NACA TN 40H) Ellperlmeatal COGftcUYe IIHI truafer wu cleter- alaecl for• colllcal forlbody (1&0 llalf-aacl•) for frN•lllr-- •elodUN • ID 400 feet per NCIOOd, · rotaUoul lpNdl • ID UOO rpm, •1le1 of utack of r/J and eo, aad for b•Uns condlUou al llftlfora aw- face t•...-ratve and llnllora ' bnter llput powar dnalty. For tb• t11n»ulent repoe, lll• reewta ••re

ln cloN" acr••••• wttll ftl11H precllctecl for two-

dlmnalOD&l bodlea Ulan witll lboM predlctecl for a COM . IUecta of rotaUOD nre lulpUlcant . J'or tbe etaUoury aplnner at eo &1111• of attack, lll• bftt• tranaler co.Ulcleota ••re I to U percent sreater oa tb• lower evface Ulan OD lll• upper Nrface. sari., bolllldary-layer trualUoD occvrecl for all coadlUou lDnaUptecl.

Inn11t1gat1on ot Pover Requirements tor Ice Prevention and Cyclical De-IoiJ:16 ot Inlet Guide Vanes vith Internal Electric Beaters.

By UVe TOn Glahn and Robert I. Blatz llACA JIM 150B29 December 1950 Abstract An investigation vae conducted to detenaine the electric power requirements for turbojet-engine inlet guide Tane1 vith continuous heating and vith cyclical de-iciJ:16 tor a range of iciJ:16 conditions.

Minimum total pover requirements for continuous heating and cyclical de-iciJ:16 are presented in tenu of average surtace datum tetJIPerature. An analysis ii included to extend the experimentally obtained contin- uous beating data to vane sizee and icing conditiou.a other than those investigated. Cyclical de-icing provides a total power saving as high as 79 percent over continuous heatillg tor a typical engine 1nstallation.

Beat-on perioda of 10 seconda or less vith heat-off perioda of 60 seconda are recommended tor c7clical de-icing.

NACA Investigations ot Icing-Protection Syetema tor Turbojet-Engine Installations.

By Uwe von Glahn, Edmwid E. Callaghan, and Vernon B. Gray BACA RM E5ll312 May 1951 Abs~raot A summary is presented of the investigations made 1n flight and in vind tunnels at the ~A Levis laboratory to determine wbi~h CIIIJ)Qnents ot turbojet engines are most critical in icing conditions and to evaluate several icing-protection methods.

Complete removal or retraction ot compressor-inlet screens upon enterbg icing conditions is reccmnended.

Surface heating appears to be the most acceptable icing- protection method, although hot-gad bleedback otters a simple method tor obtaining icing protection on some !.nstallations.

:-IACA RM E57G09 N. tion.11 Ad\'lt ry Committee ror A•ronautlca .

TOTAL-PRESSURE DISTORTIOS AND RECOVERY or Sl.PERSO . IC Na!£ fNLET WITH CONICAL CESTERBODY IN SUBSONIC ICING CONDITIONS.

1'homaa r. Get~r. S•pt•mt>er 1957. 41p. dlacra., not<». (NACA RM £57G09) CONflDENTlAL k• w .- a fc rmed on a futt-aral• unheated auperaonl . c n in e lnl•t ov er a r:in1• of rond111on1 In the NACA Lno'lt 1r1n1 I nnet to ~ttraune ill effect on mpreuor - f.tr• tot.tl -p ruaun d11tortlon and recovery . Tht addit i on ol let to the Inlet compo- nent, lnrr•ned d11torllon ltvela and decre&Nd r•• rovery vatuu compared with clear-llr rtaulta, the IOHH l ncreu1nc With llmt ln kln,. The combllla• lion ol glue let, Mgh rorrtcted -•&ht flow, and hl&h angle of alt.ark )'lllded lht hl1hul levtla ol die- t rllon .tnd lowut Vllluea ol rerovery .

ID,_ttsat1on ot ~o and Ioing Charaoter1 • ttaa at Vater-Inert1a-S.parat1on Inlete tor 'l'ur'boJe\

Zasim • •

17 ~ Ton Glahn and Robert I. Blat1 11ACA IIC ESOE03 July 1950 Abstract Aerodynamic ain loins investigations or several internal water-inertia-separation inlets de&iEPled to prevent entrance of voter into a turbojet engine in an icing condition are presented. Comparisons of total- preseure loss, mass flov, am icing characteristics are made.

Complete 1olng protection of inlet guide vanes vaa not aohiend. Approximately 9 percent of the volume or water enterins the inlets remained in the atr. For non- loins operation, total-preseure losses were canperable to those of direct-ram inlets. Under icins conditions, consi,erable total-pressure losses vere obtained vith inertia-s~paratton inlets.

Wing lcin& Protection AN ANAL\" IS OF THE DI IPATION OF HEAT IN CO1'l>ITIOS OF ICING FRO~t .~ ECTION OF THE WING OF THE C-16 AlRPLAl"<iE J. K Huor SUMI\UI.Y A nutlwJ i giom for calrulati11g tlie ltmprralure tliat a 11urjau, Ji,-atrcl inltmally by air, toiU auvme ill 1qircifi d C01'· dilicms of icing. Tlie mttAod COIi bt applitd gn1 rally to prt- diet tAe pt1Jorma11ce, tmdu ~o,ulitio11.S of icing, of tlit tl1trn1al systnn for proftcting aircraft. lulculati<>t1 · Aarv bun made for a 1tctio11 of IAt vring of lM 46 airpla11r, a,1d tlit rttr'ult11 agru cl0$tly tpjtJi. IAe ttmptratu.r ~ mt'fU11rrd. Tiu limit ,if prot ction, dtr1 Ult tetn11rrah,rt of tilt fltlrjact rtochts :JS Ji', /uJ btt11 prtdidt.d for 'lit lraJi11g t,dgt. The trmprratvrr of tlie 1111rfau in condition of irfog •>itli afr at 0° F alllo Aa 6 11 calo1at J. Tlat tJftrl of J:i11ttir 1't"ati11g a,wl tlir tjfrrt <>J tlit conce11tratio11 of Jr e tLol r a,id ,i.t of dropltt in tht rloud art Jtn10,1~trafrd.

NATlONAL ADVlUOlY CCH.\l'l'l'El:: 1'011 AEltO?WJ'l'lCS .rr.cHNlCAL NO'l'E NO. llf(2 THE CALCULATIOlf OJ' TB!: BEA!~ FOB WINO TBERW. ICE PREVE?fl'lOlf IN SPf.CIFilJ) lCmG CONDI1'IO?E By Carr B. ?leel, Jr. , :Noman R. Bergnm, Do.vid Jwcoff, and Bernard. A. Sahlaff As a reault or a !W'ldamental 1nveat1f31!t1on or the mteoroloeic.ll conditiona conducive to the formation or ice on aircraft and a stu~ of tha process of airfoil thermnl. ice prenntion, prev1oual1 derived eqwst1ons for calculatins the rate or heat transfer !rem a1r!oila in icine conditions vere verified. Knowledge ot the mmmer 1n vh1ch vater 1a depooited on and evaporated fl-cc the surface of a heated airfoil vas exve.ndod oufficiently to allov reosonnbly accurate co.le~ l~tions of airfoil heat roqu1remonts. The resee.rcb conaiated of flight teots in natural-icil"l8 conditions v1th tvo ~toot-chord heated airfoils or different sections. Measurements of the meteorological.

ve.riableo conducive to See formation were made eimultaneouel1 vith the procurement or airfoil thermal data.

It ve.e concludod that the extent of knovledge on the meteorology of ici~, the 1.mpinge~nt or water drops on airfoil surfaces, and the

proceoeee or heat transfer e.nd evaporation rrcm a wetted airfoil

surface bas been 1ncreneed to a point vh~re th e doaign of heated v1n~s on a f\mdomental, wet--<l1r bas1e nov can be undertaken with reasonable certainty.

NACA RM IIUII NatlOllal AdnaorJ ComauttH for Aerouutlca.

PULDUNARY UIULTI or CYCLICAL DI-ICING or A OAl·HUT&l> AIRFOIL. v. B. Gray, D. T.

Bowdea ud U. ,_ Glalul. .1Ulal'J llU. Hp .

photoe., cUaara. , tab. (NACA RM ;;mn•>

Aa NACA II• -Ill alrfoll of I-foot dloNI WU pro- Tided wWl a pa-bealed l .......... for laTffUla• UOM ol c,cllcal dit-ldal, De-lcllll ... acc:oa- pllabed WWI llllermlttNt ...... ol alrfoll .......

that ...,Ued bot pa to cllorchrtN,....... la a

cblble-alr.lll c:outructJon . b remGft1 wu faclll-

talud bJ a apuwlN l•clllll-e ;,;e putllll •rtp wlllc:b wu ccmtilMaolaalJ IINlecl from lbe su•IIIPPIJ duct.

Prellmlnary re1.•lt1 d • mon • trate t.llal • atl1fadC\l'J c,cllcal lee remo r.\l orcua with ratloa of total cJd• Um• to beal-o11 perlOd from 10 to 18.

NACA llll 111130 National AdYtaal'J Comm lttff for Aeroaauttc •• PRELDIINARY INVl8TlGA110N or CYClJC D1- JClNO or AN AIRFOlL U!IING AN IXTIRNAL ILICTRIC DATER . lame • p, Lew and Deall T.

Bowden. PebnaarJ 1152. Up. pbotoa., cllqr •• (NACA RM 151130) An tmeatlptlon was conducted ln the NACA Lewi• lclnl rea•rc:b t1&Mel to determine the cbancterla- uca and requlremero of c,cllc de-lclnt of u alrfoU bJ uN of an Ulernal electric beater. TIM preNllt lnnatlptlon waa llmlted to u 1lr11teed ol lTI mUH per bOlll'. Data are preNntecl to llhow lbe etfecta ol nrlaUona tn lint-on and beat-oa perloda, ambteat alr temperature, llquld-nter c:oatent, &111l• ol attack and beaUnc dlatrtbution on the req\llremeata for

c,cllc de-lcl.JII. Tbt Hternal beat now at '1lrlou

lctn, and beatlns conditlou la al90 prtHaled. A contlnuoualJ bftted partq • trip at lbe alrfoU lNd- lJII eels• •• follnd neceN1r, for qulcll, complete, and conalatent let remOYal. Thoe cJcllc power re- 41ulrtmenta ••r• fol&lld to i,. prlmarlly a fllllCtlon ol lbe datum temperature and beat-on tlme, wlth the other operallnc and meteorol01lcal nrlablea bHlnl a aecond-order eUect . Short beat-on perloda and blab powar densltlea reaulted ln the moat efflcltnl let r--=>onl, lbe mlnlmWD enerc, input, and lbe mllll- mum rllllbacll lc:e formallona .

..

88 NACA TN 14111

National Ad'riao11 CommlttN for AeroaautlcL

. COMPARI80N or BUT TllANIHll nu:>11 AIRPCJIL

IN NATUllAL AND IIMULAT&D ICING CONDITICIIII,

Tlloma • r. Gelder ud Jame • P, Lewta. September

1161. llp. dlqrL, pbotoa., I taba. (NACA TN 14111) An uperlmeatal lmeltipUon of tlle beat tralUlfer from u 1-foot-cllonl atrfoU model lll dear air ud lll almulated lcllll c:ondttloa1 waa ICCIDdledtd la Ille tel111 tunnel. TbeN rftlllta are com.-nd wltll tlaoN obtained ln a filpt llffeltipUoa wltll tile aame aodel at almllar apenttns comllt1oaL 'l'bl tuanel n..ita

llldlcate Ille .erect al taml turbulence bJ Ille forwanl

m0Ye1111nt of tnnaltloa from laminar to turbulmt hat tranafer. Tbe fitpt reault1 tndicate tbat Ille comectlft beat tnuler ln tel111 ta c:onaldenblJ different from tbat meuured ln clear a!.J' and oalJ au,titlJ dWerent from tbat obtained tn tile tunnel durlJII almulated lclJII.

NACA TN 21114 Natlonal Advisory Committee for Aeronautics.

A METHOD FOR RAPID DETERMINATION or THE

ICING LIMIT OF A BODY IN TERMS OF THE n'REAM CONDITIONS. Edmund E. Callapan and John S. Serafini. March 11153 . 33p. diagra .

(NACA TN 21114) The eflecta of exl1Un1 frlcUonal heattns were ana- lysed to determine the condlUona under which Ice formatlona on aircraft aurracea can be prevented. A me hod l1 presented for rapidly determining by mean• of chart a the combination of Mach number, altitude, and 1tream temperature which wUI maintain an let -free 1urface In an Icing cloud. The method can be applied to both aubaonlc and supereonic now.

The chart• presented are fo:r Mach numbers up to l . 8 and preaaure altitudes from aea level to 45,000 feet.

NACATN IHI NaUonal AdYieorJ CommlltN for Aeroaautlca.

ANALYTICAL DfVUTJGATION or ICING LDIIT

POR DIAMOND·IIIAPSD AlllPOlL Df TIIAMIONJC AND IUPEUON1C l'LOW. · Sdmund S. Callapu and .John I. leraflAl . .J~ HU. lip. diap'a.

(NACA TN 1111) Calc1alaUona haft bNll made for tbe lclAI l1m1t ol a clwDond 1\rfoU at aero allll• ol attack lll terma ol the atnam Mach lllllllber, •ream temperature, ud

prHeure alUtude. The lclAI llmlt la clelllled u a

wetted-•urface temperature of II° r aal la ~ed

to the atrnm condltlou bJ tb• mM!lod of Bard,.

Th• rHWtl abow that tb1 polat mollt UulJ to lee Oil

tbe airfoil llH lmmediatelJ behllld tbe abol&lde r and 111ubJ1ct to po1a1bl1 lclAI at Mach lllllllbere u la1p u1.,.

NACA RM E5llC21 National AdvillOrJ Committee for Aeronautlc1.

DE-ICING AND RUNBACK CHARACTERLffICS OF THREE CYCLIC, ELECTRIC, !:XTERNAL DE-ICING BOOTS EMPLOYING CHORDWISE SHEDDING.

Robert 8. Ru11erl. MaJ Ul5ll . llap. pbotoe . , c11a&r1. (NACA RM E5llC21) The performance characterlatlc1 of tbrN cycllc, electric, rubber-clad de-lclnc boota were en.luated.

lach boot wu operated in lcin1 at deal.p apeclflca- Uona of 21 watll per aquare inch for cycled areu, Ill watt1 per 1quare Inch for contlnuoualy bated parlllll 1trlp1, a beat-on time of 10 MConcle, and a cycle ratio of 10. For a frH-ltream Yeloclty of

approximately 395 fell per 1econd, the rans• of frN•

1tream total temperature at which the iclns protec- Uon afforded by the varloua boot• became marpnal wu from 12° lo 15° F for valuH of llquld-water content employed. The runback characterlaUca of the boot• were 1lmllar . The forward cycled 1ecment1, upper and lower 1urface1, were the moat critical areu for the thrN boot• inveatlpled .

'

.,

IIACA 11111 IUCH Natloaal Adneol'J CoamlltN for AeroMuUca,

COIIP.AJUION or BVIIIAL IIITIIODI or CYCLIC

DIE-ICDIG or A GAI-HSATID Allll'OIL, VerllDII

a. an, and Deu T. aowden. .r ... 1tu. Np.

dla&n , , pllotoe. , I tabe. (NACA 11111 IUCIT) leffrll melboda ol c7cUc de-lcllll .J • pa-a..ted alrf.oU were laftlllpted to determlM lce-remoftl cllancttrlatlce and -"Ill reqlllremnta. TM c,cUc dt-lcllll 11Jeltm wllb I apuwtN lee-fl'N putllll lltrlp la lbe et1paUoe Pesl,oe ud I c:ou&ut· temperature IU·MPPlJ Ml 11ft lb• .-&cu• ud moat reliable lee relllOftl. Bnlilll reqlW'UMNlle for the NHral metbode ol cyclic dt•ldAI are compared, ud the unnp oftr contlauoua lee preftllUon are lbown. Data an pnNnted to lbow the nlatloe of eurfac1 temperature, rate of lllll'fact llntial, ud llntlnl tune to the relDOYll of lee.

NACA TN 3130 National Advl10ry Committee for Aeronaullc1.

A PROCEDURE FOR THE DESJON OF AIR-HEATED ICE-PREVENTION 8YS1' EMS, Carr B. Neel, Jr.

Jwie 11154. 63p. dla&r •., photo. (NACA TN 31:S0) The procedure to bl follo•ed In the de1l1n of air• craft lee-prevention equipment ln which lhe compo- nent• are protected by meane of lnttrnall)' circulated heated air 1 • outllntd. In addition lo pre • enlaUon of lht! required heat-tran1(11 and alr-pru • ure-loH equation •, a • lmple electrical analo&W 11 de • crlbed which wu devl • ed to facllltate lhe de • l&n of an alr- heated • y • ttm. An llluetratlon 1 • Jiven of the appllcallon of the analoaue to a dt1l1n problem.

NACA 1111 SHIOI NalloMl AftleorJ COIIUllitl .. lor Ael'OMUtlca.

INVUTIOATJON or POIIOIJ. OAI-RSATm>

LIADINO-SDOI acnON l'OII ICINO PIIOflCTION or A DILTA WINO. Dau T. Bowlin. ., • ..., 1111, 14p ........ , pllotoe., tab. CNACA 1111 Sl4IOI) An lll\ONUptton wu COftduca.d In Ille NACA Lftla

lcllll ,....,rc:11 tunnel lo clelermlne 11eau111 r..-re-

.. nt• and charactertattca ol a pa-lleated poroua lNdlni-edp ., .... lor Ull-lClfll ol a delta ......

Adequate lclnl proteeUoll wu obtained lor all lcllll

condlUona ln•eaUpted. Larfl •nap tn pa now

maJ be reall&ed by aNlinl hall tlle ....-r-alU'lace

poroua ar•. Du now Ulroup Ille poroua area

callNd onlJ a allpt lncr .... In aJrt '> U clr&1 ar..d ball ., appreciable .Uect on airfoil preuve dlatrtbutloa.

Olue-ki lorinallo:ia on U.. unbated a.arloll callNd rapid lncr- • In NCUon clras .

:AACA RM 1:!11821 .National Adv!.aorJ Commlltff lor Atronaullce .

1,EAT REQUIREMENTS FOR ICE PROTECTION Of A GYCLICALLY GAS-HEATED, H SWEPT AIR• l'Oll. WITH PARTIAL-SPAN LEADINO-EDOE SLAT .

Veraon H. Oray and Uwt H. Von Glahn. MaJ IHI .

Tap . dia&ra ., pbotoa., tab • . (NACA RM l:HBH) He • tlnc rttqulremeni. for ut11ractor1 c,cllc dt- lchic o••r a wlcw rans• of lclrc and operalln( :ondl- llona haH bt H obta1ned for a IU·btaled, 31° INpl airfoil wlU1 a partial-apan le&dinc•eclc• alat. Com- )Uiaona of healln( requlr1m1nta were madt belWNn Ole 1l alled and unalatted porUona of the airfoil and bett. · ten cyc:llc dt-lclnc and CODllnuoua anll-lcilll , Cy clic dt•lClrJ& ay111m1 WIUI and without luduic- •d& • lce-lrtf par11n1 atrlpa wue alao evaluated.

&tfeot1TeDee • ot Thezw.J.·Pncn11at1o Airtoll•Ice-

Proteot1o· a,ata.

II W1ll1• B. Oovu, Jr., aD4 Donald I. *lholl.an4

IACA JIC ISC&l.0&

April 19,1

Abetract

Ic1QS and~ 1nTeat1gat1oaa nn con4ucte4 1n

the IACA L ,via 1c1Da naearch twmel OD a thenu.l·

pae111111.tio 4e-1cer aounted OD a ,2-1ncb-chord. IACA 0018

a1rtu1l. Mars1D&l ponr 4eaa1t1ea tor the lea41DS•edae

electricnll.7 heated area nre obtained. Drag coapa.ri-

eona nn all.de between the bare airfoil aD4 tbe Tarioua

operatinr& con41t1om ot the pie\ll&tic aection ot t.m

de-icer dur1Q8 1c1Q8 aD4 non1c1ng ot the airtoll aur-

tace.

Performance Penaltiea

NACA RM E53J30 National A. dvlaory Commltlff for A.tronalltlc •.

EFFECT OF ICE FORMATIONS ON SECTION DRAG OF SWEPT NACA 63A - OOII AIRFOIL WITH PARTlAlr SPAN LEADING - EDGE SLAT FOR VARIOUS MODES OF THERMAL I CE PROTECTION. Uwe H. von Glahr a1td Vernon H. Gray . Mar h 1154. 59p. dla i;n., photo:.. (N ACA RM £53J30) SIIM!s • w re mad I determine the effect of Ice fo rm I n• on th serli n drac of a 6. 11 - fout -o rd 36° • ~• ACA 63 A -OOII alrf II with par11al-ap n I d 111 -ed.i alat. In I I nl , the r ln of a thin n pt alrf II Ill r 111lt In cruter a rodynan1lc penalllu th.i n fo r a lhl e ll. 11n1w~t 1rfoll. Glau-I ce I rn 11 on1 t th I di n d I the airfoil cal!Md tare nr re • • In H e llon drag I en at a llqu d-water cont nt o f 0.311 er m per cub r met r . TIie 11N of 111 I - Ire parltn 11rlp In the II Ml n repon caund a n ll&lbl ch n n dra1 cc mpared with a com- pl tely unhuted alrf II . Cyclic de - lcln& wtlffl p r rly applied 1111 1d the drac to decreue almoet I th b r -1ir f I dra, ¥1hltl.

NACATNINI ti

Na&IOMl AdYleor, Coaallt• lor Ae.,....•

•rnCT or IC • AMO nmr POIIIIAft>NI °"

DIIAO or NACA 111-lll Alll,OU. POii YAIIIDUI IIIIODII or TIIDMA.L ICS PIIOl'SCTIDN. ..,_ •. an,_. u.. • .... caua. ,_ 1111. •· ..., • . , fMIN . (NACA TN INI) .... "" ... lo ... ,.. ..... .a• of lee ...

froat fot..UO. OIi die drac of u l•foot--CMrlll NACA 111-111 urfo&l. Al llilll UIII• of 1111aCk ( • o), ll&H-lce for..UO. oa UM! ..,.r ~-, 1M

I..._ Hp of u airfoil u... l&rll Iller ..... &a

... ud lllclplHl alallllll of LIie aartoll. llaallMk lclnl 011 Ula lower evface, nce,t for ._., .,...

WIN lu ridpe, preMtllecl ao Nrlou dr11 pralll ... .

lllme-lce for..UOU oa the ,...., edp dul aot «:allN l&rp drac uicr ... e. C1cUc ••lcilll ol 1M lndlac .... IMICCHefllllJ clecrNNCI Ille ..... lllDCl • l

IO the bar• airfoil drac ftlue . rroa foraatlou °"

alrf t ll aurfacH callNd iarp drac 111c,..... .- .. , rHlllt 111 eta1U111 of LIie airfoil .

!f'tecta at le• J01"11&t1ona on Airplane Pertcma- ance 1n Lnel Cruiaing JU.pt.

!7 o. Merritt PrNton and CalTin C. !lackmaD

llACA Tl lo. 1598 Na1 19'8 Abatract Flight 1nnat1gat1on 1n natural 1o1na con41- t1ona vu co · r.11 · 11 oted ~o detennine ettect at ice accretion on idrplane performance.

Muil.1'14 loe1 1n propeller etr1e1enc7 mcoun- tered vu 19 perce n t. During 87 percent at tlie propeller 1c ins encounter., lOPea of 10 porcent or leH vere ob1erved. Ice tormaticne on all CCIII• pononte at the airplane except the propellen dur- 1116 i 1ng encounter reaul ted 1n an 1ncreue 1n pe.ruite 4r&e at the airplane at 81 percent. The control re1ponae or the airplane in tb11 conditioo vu marginal.

NACATN 1111 National Adriaol"J CommlttN for Ael'Wlltlca.

ICING PROTECTION ,OR A TURBOIST TRIJCI- PORT AIRPLANS: BUTINO UQUIR.SIUNTI, IIETROOS OF PROTECTION, AND PEIU'ORIIANCII:

Pll:NALTIU. Tllomu r. Gelder, JameaP. Lnta

ud Stanley L. K.ouu. Janu&rJ 1153. I, Hp.

diaar•• , tab. (NACA TN 1111) Tbe 11eaUJ1C requirement• !or NTenl mltboda of • lclnl p1otec:Uon for• typical tlll'bojet truaport air-

plane operat1al cmr a probable ranee of lclnl coadl-

tiou are eftluated, and the airplane perfonnuce penaltiH auoclalecl With proYidini thla protection

from ftl'lou ••ru • olll'CH are uHaNCl. Coa-

Uaiaoua heatlal reqlliremeata and airplane peaalUea for the tu.rbojet tra.aaport are c:oulderably tncreued over tbo• for lower-apeecl aircraft. Beatial re- qldremenu can be aubataatia1ly reduced by uae of a cyclic de-lclnc eyfltem and choice of Ule proper enerl)' aou.rce.

NACA TN 3564 National Advlaory Committee for Aeronautic•.

EFFECT OF PNEUMATIC DE-ICERS AND ICE FORMATIONS ON AERODYNAMIC CR.-.RACTEll!S- TICS OF AN AIRFOIL . Dean T . Bowden. February 1956. 59p. diagr1., photoa. (NACA TN 3564) Meuure;,,enta of drag, lift, and pitchinl moment of an NACA \>011 airfoil were made in icln1 condition • uelr.g pnewnatic de-lcera havin1 either apanwiH or chordwlee inflatable tubea. Lift and drag penaltlea due to de-icer inflation and to Ice remalninl after de- icer Inflation are presented. lnflalion of the 1panwlee-tube de-icer cauaed a much greater ln- creue in drag than Inflation of the chordwlae-tube de-icer . The two de-teen were equally effective 1n removing Ice. Lilt and drag penaltle • re • ultlng from Ice formed wlt .h the de-icer inoperative are alao pre- 1ented, as well u apoiler data for analyzln& drag lncreuea due to Ice formation• .

NACATN4UI NaUoaal Aclriaory Co~ for A.......Uc:a.

CORJlELATIONI AMONG ICI IUASUUIIDTI, DlPINGEIIENT RATU, ICING CONDITIONI, AND IJllAQ COEFFICI.INTI 10R UNIWIPT NACA tlAOCM AlllfOIL , Venoa B. Ora:,. rebrll&l'f IHI. ,.,.

dlair••• pbo.,oa ., -.. (KACA TN 4151) Aa eJllldrtcal relaUoll la dartffd bJ wlllcll dlaps ID NctiaG cine coefflcl•ta dDe to Ice oa • NACA IUOCM a1rfoll are c:alcuble from lmOn ldq Md openUDc coedlllcu. 'l'u correlatloo la GblalaN bJ ue of mcuved Ice Mlpta ad let....-. ldtlal ice ftlpta are ID llp'Nmelll wltb droplat imp&ap• ment data; ID sJa,M CD11dllioll1, ice welpta lacr ...

at procreulHly sreater rate • wliJI U.ma.

NACA TN 4155 National Advlaory Committ.N for Aerouatica.

AERODYNAIIJC EFFECTS CAUSED BT ICING OF AN UNSWEPT NACA HA004 AIRFOIL . VerDOD B.

Gray and Uwe B. YOII Gla.bo . flbrar:, IHI. 41p.

dlair • ,, paotoa., taba. (NACA TtUU5) At aqlea of attack ltH Uwl 40 botll rime and sl&H· lee formaUooa lDcreued drq, reduced lift, ad reduced d1'f1nl momeota . At anpea of attack sreater tban 4°, cine coetfldnta lncnued wltb 11,ut•lce

formation • and decreued wltb rime lee; Wt coem-

denta seoerally lncreued with pue let ud were nrtably affected bJ rime lee ; pltchlos-mom•t cbanle• were rather erratic and depeadecl Oil tbe lee eape . When tbe airfoil wa.a iced at b1p 1111,lea of attack aod rotated to lower ansl11, tarse oepUH pltchln& momnta • ~ re obtallltd . ke formaUou OD tbe airfoil bad DO 111Clllflcaut .Ueda OD CODtrol- 1urface b1qe momeota .

.,

NASA Til D-21116 National Aeronautics and Space Adminlatratioo .

PREDICTION OF AERODYNAMIC PENALTIES CAUSED BY ICE FORMATIONS ON VARIOUS AIRFOILS. Vernon H. Gray . February 1964. 19p.

OTS p:-lce, $0 . 50 .

(NASA TECHNICAL NOTE D-2166) An equation la presented by which changes in drag coeUlclents due to lee formations on airfoils with thickness ratios up to 15 percent may be calculated from known Icing and flight condlllon1. Bued on limited data, changea In lift and pitching-moment coemctenta due to Ice on thick, blunt airfoils may be estimated frcm the ..:orrespondlng changes ln drag coefficients: for thin airfoils at higher angles of attack no general relation Is obtained .

Windshield Icing Protection NACA TECHNICAL NOTE 1434 A METHOD FOR CALCULATING THE HEAT REQUIRED FOR WINDSHIELD THERMAL ICE PREVENTION BASED ON EXTENSIVE FLIGHT TESTS IN NATURAL ICING CONDITIONS Alun R. Jones, George H. Holdaway, and Charles P. Steinmetz SUMMARY An equation is presented for calculating the heat flow required from the surface of an internally heated windshield in order to prevent the formation of ice accretions during flight in specified icing con- ditions. To ascertain the validity of the equation, comparison is made between calculated values of the beat required and measured values ob- tained for test windshield in actual flights in icing conditions.

The test windshields were internally heated and provided data applicable to two comm on types of windshield configurations; namely the V-type and the type in s talled flush with the fuselage contours. These windshields were installed on a twin-engine cargo airplane and the icing flights were conducted over a large area of the United States during the winters of 1945-46 and 1946-47. In addition to the internally heated windshield investigation, some test data we re obtained for a windshield ic e -prevention system in vhirh heated air was discharged into the wind- shield boundary layer • .,

MCA 1111 a111n,.

Natlcmal AdYiJiorJ CommlttN for Aercmautlca.

PRELDIINARa DATA ON RAIN DU'l&CflON FROM AIRCRAn WJNDIHIELDI BY llliNI 01' BIGB- VELOCITY JET-AIR BLAST. Rablrt I. JtugerL July lt55. l'Jp. dlqra., pbotoa. (MACA RM SHE 1'a} RHulta lndlcate that ra1D del1ectloD bJ Jet-air bLUt appear • feuible for fllpt .,._. c-.,anble wWa laDdiDc and take-off; bowHer, '1aibllltJ tbroup tbe alat pnerated bJ ra1Ddrop break"' pl'Nllll • a prob- lem. For Ult almulaled wtndalaleld 1181d, air-flow ratH of aboat S.S lb/min-I.A. of apu were nqmred for adequate ra1D defiecUon at u air • pNd of 135 mph. A method wu denNd whereby Lup-cltameter water drop • (1000 to 1500 .,_) can be produced ill a moYinJ air • tram, without breakup, at • pNde ill HCIU of 175 mph.

Cooling Fan Icing Protection NACA TECHNICAL NOTE 1246 WIND-TUNNEL INVESTIGATION OF ICING OF AN ENGINE COOLING-FAN INSTALLATION James P. Lewis SUMMARY An investigation was made of the icing characteristics and means of ice protection of a tYPical radial-engine cooling-fan installation.

The investigation was made at various icing and performance conditions in the icing research tunnel of the NACA Cleveland laboratory.

The icing of the unprotected cooling-fan installation was found to present a serious operational problem. Reduction in air flow below the minimum value requir ed for engine cooling-air flow through the fan assembly occurred in as little as 5 minutes under normal icing conditions.

Steam de-icing was found to be effective for the cowling lip and inlet duct. Alcohol de-icing of the fan blades and stator vanes was found to be unsatisfactory. Electrical heat de-icing of the fan blades was found to be effective but de-icing of the stator vanes was not com- pletely effective at the power densities investigated • .,

lladome Icing Protection

NACADIJSUAU NaUoaal AdTlaory COIIUlllttM for Aeronullca .

· AN ANALYTICAL ffUDYOF IIJSAT UQUIRS- MENTS FOR ICING PROTECTION OF RANDOIIU .

Jamea P. Lewla. March ltu. IOp. dlaen, (NA.CA RII EUAU) The heat reqlllrementa for tbe lclnl protection of two radome confiprationa have been atudled ov.tr a nap or dealgn lclnl condltlona. Both the protection limit• or a typical thermal protection ayatem and the rela- tive effecta of tbe varloua lclnc nrlablea have been determlned. For fllll evaporation of all lmplfflllll water, an effecttve heat denalty of 14 watt• per aquare lncb wu ,ecilllred. When a comblnalion of tbe fllll eqporation and l'IIDDln& wet aurface ay--m• wu employed, a beat reqlllrement of 5 watta per aquare inch provided protection at nnre lclnC and operatilll conditiona.

NA.CA RM E52.r.il National Advi110ry Committee for Aeronaldlca.

EXPERIMENTAL INVESTIGATION OF RADOIIE ICING AND ICING PROTECTION. Jamu P. Lewta and Robert J . Blade. January 11153 . eo,. dlacr•-, photoa. (NACA RII E52J31) In an lnveaucallon or radome icing and icing protec- tion ln the NACA Lewta icing reNarcb t11Mel, the impingement of water and the formation of ice o .. '. W<> radome contlguratlona were found to acree well with theory and experience. The lee formationa on the radomea produced aerioua ertecta on radar perform- ancf!. The ethylene pycol fillld-protection ayatem gave adequate lcl111 protection fo 1 · both ami-lclnl and de-Icing. The radowea were tn, ~atigated at alr- apeeda up to 290 mllH per hour, air total tempera- ture& or -15° to 200 F, water .:ontenta up to 1. O gram per cubic meter, and anclea of attack of rl' and 40,

Antenna Icing Determination of A1rcr&tt Antenna Load• Produced b7 latural I0i116 Con41t1ana.

BJ William L. Kepple BACA RM lo. 17B26& Februar;r 194A ' Abstract Fresente the effect of 41stanco flow:: in the icitig region, antenna length, an4 antenna &Dgle on tbe ten- don occurr1Il6 in aircraft antennas.

Antenna tension 1ncreasei vitb ant.en.."ll' - anc;le.

The maxiJDUI:i te~sions recorded were: o to 15° - 68 pound.a 44o - 274 founds 64° - 459 pounds 111 Vibration and Icillg Innet18ation at CAA Tn,e V-109 Ver1-B16h-J'requenc7 Aircraft Antenna.

B7 William R. Gowan, Jr.

BACA BM Jo. SEgJ)20 Abstract Vibration and icing cbaracteriatioa wre 1nTe1ti- gated 1n the BACA 1c1Dg research tumel on a CAA tJ'l)e V-109 Te17-h1gb-rrequenc7 aircraft antenna propoaed tor amn141rect10Dl!ll-range operation. Vibr4t1on of the antenna elements vaa obael"'f'ed for beth 1c1Dg and non- icing con41t1ona. Ma.ximu:m Tibrat1on am~l1tu4e obaened •• approxilll&tel7 7 1.nche,s at the end at an element 24 inches lons 4uri116 101.ng, and failure of an elment occurred 1n one inatanee 41,lj ? ing 101.na. Vibration with- out ice accretion vaa not aer1ere.

Ll .1

Inlet and V~nc Icing Protection

112 Inveatigation ot Aerod.1nam1c am IciDg Cblracter1at1oa

or Bece • eed I\J.el-Vent Conf1gurat1ona.

:S, Robert S. Bugser1, lJve 'TOD Glahn., and Vern G. Bollin NACA 'l'N No. 1789 March 19'9 Abstract A:rl imest1gat1on vae conducted to determine aero- d,ynmnic e.nd icing character1et1ce ot aeveral receeee4 , tuel-vent cont1gurati011l~.

The vent configuration having diverging ramp • ide- valle, 1° ramp IUlgle, and vent tubes manifolded to a plenum chamber gave greatest vent-tube preueuree for all conditions 1nveetigated. Contigurat10lllll vitb diverging ramp eidewlla save greater Tent-tube preeaures than configurations with parallel aidewalle. In 11milar cloud- icing conditiooe, only the configuration with a plenum chamber maintained adequate vent-tube preesuree through- out 60-micute icine periods. Bo complete cloBUN of vent-tube openings due to ice tormat1one occurred tar configurations investigated.

Jet Penetration NACA TECHNICAL NOTE 1615 INVESTIGATION OF THE PENETRATION OF AN AIR J.CT DIRECTED PERPENDICULARLY TO AN AIR STREAM Edmund E. Callaghan and Robert S. Ruggeri SUMMARY An experimental investigation vas conducted to determine the pene- tration of a circular air Jet directed perpendicularly to an air stream as a function of Jet density. Jet velocity. air-itre&m density. air-stream velocity, Je t diameter, and distance downstream from the jet. The pene- tration was determined tor nearly constant values ot air-stream density at two tunnel velocities, tour jet diameters, tour positions downstream of the Je t . and tor a large range ot Jet velocities and densities. An equation tor the penetration was obtained in terms of the Jet diameter, the distance dovnstream from the Jet, and the ratios ot Jet and air-stream velocities ~nd densities.

Penetration ot Air Jeta I • IN1D8 trm Ciroular, Square, an4 lll1pt1oal Or1t1oe • D1rec+.Ad Perpen41oalarl7 to an A1r Stl'NII.

B7 Bobert 8. 1'lger1, Mw,na B. Callagbm, aD4 Dean 'f. Bawden IIACA TJI 2019 February 1950 Abstract The penetration or air Jeta directed perpendicul&rl.7 to an air • treaa vu experillental.17 dete1"111ned. Jet • isauins t'r(a circular, • quare, and elliptical or1tioe • vere 1nTe • t1pted and tbe penetratioo at a poaitioo down• • treaa ot tbe orifice vu determined u e. tunotioo or Jet den • i t7, ,1et 't'elooi t7, air-etream den • i t;r, air-etrea 't'elocit7, ettecti..e Jet diameter, and orifice tlov coet- ricient. Beaults are correlated 1n terms of dimenaionleH pare.meter • and tbe penetrationa obtained Yo.th ftriOllll abapea ~ cc:mpared.

Greater penetre.tiooa vere obtained with aquare orifices than Yith circular oriticea ot equal area.

Investigation ot Flow Coefficient ot Circular, Square, and Elliptical Orifices at High Pressure Ratios.

By Edmund E. Callaghan and Deen T. Bowden NACA TN 1947 Abstract An experimental 1:lvest1gation was conducted to determine orifice coefficients of a Jet directed perpendicularly to an air stream as a function of pressure ratio and Jet Reynolds number tor elliptical, square, and circular orifices. Et'fect of air-stream velocity on Jet flow vas determined tor three tunnel- air velocities. Equations tor flow coefficient 1n tems ot Jet Reynolds number and pressure ratio were obtained for n.rious shapes.

Excellent correlation was obtained between results tor Jet discharging into still air and results tor Jet discharging into movlns air stream, ~rovided that correct outlet preeeure was used.

NACATNHH National Advtaor, CommlttN for Aeronaut!ca.

GENERAL CORRELATION OF TSMPERATURJ:

PROnLES DOWNSTREAM or A HEATED AIR BT

DIRJ:C1' &D AT VARIOUS ANGLU TO AIR ITRLUI.

Robert I. Rugeri . December 1912. Hp. dlaira., tab . (NACA TN 2155) An •JIPlrlmental lnHatt&atlon wu conducted to dt· term1Dt tbe temperature profile downatream of • · heated-air jet directed at nrloua 1111111 to an air atream . The profllta were determined at two poal- tlou downatrnm of the Jet u a function of jtt dlameter, jtt denalty, frN-atream denalty, Jet .. loclty, free-atream •eloclty, jet total temperature, orifice Oow coefficient, and Jet dlacharle .ulllta , A method la prtHnttd wblcll yielda a 1ood approsi- mation of tbe temperature profile ln term• of dlmtn- aionleaa parameter• of t.be Oow and 1eometric con- ditiona.

117 NACA TN 3488

National Ach110r, Committee for Afronautica.

A GENERAL CCWtRELATlON OF T!.MPERATURI PROFILES DOWNSTREAM OP' A il!ATED AIR lET DIRECTED PERPENDICULARLY TO AN AIR STREAM. Edmund E. Callqban and Robert I.

Ruaeri. September 11151. 3'1p. dlasra. (NACA !'N 24H) An uperlmental lnveatlpUoo was conducted to dtte,.

mlne tbe temperature profile do.matream of a bated air jet directed perpendicularly to an air atream.

Tbe profllta were dttermir,ed at MYtnl poalUou do-strum oft.be Jet u a function of Jtt ••tJ, free-atream deutty, jet YelocltJ, Jtt temperature, free-stream Teloctty, and orifice Oow coefftcteat. A method ts preaerted wllicb ylelda a Sood appro&lma- Uon oft.be tempenture profile ln termaof dimelllllon- less parameters of tbe now and 1eometrlc condiUona.

Beat Tran • fer

118 Dlpronmezit • 1n Beat Tranater tor Anti-loins ot au-

Heated A1rto1le v1 th Internal 11.na and Part.1 tiane.

IIACA TN 2126 July 1950 Abetraot Tm ettect1Tene •• ot intel'DAl f1nntng 1n airfoil• vu anal.7&ed to 4eterm1Jle 4ee1sn 'Tal'iablee b7 vhioh local • urtace heat tranater -, be ett1oienti, ccntrolled.

CcaparatSn iDTe • t1gat1011 • ot pa-heated hollow a1rto111 indicate that • urtaoe-btat.ing ratee tor 1oe pre'ff1lt1cn -, be 1noreaee4 up to 3.5 timla b7 the a4dit1cn ot •tal tw and tlov-ccm1'1ning partition • to the a1rto1l internal pueage.

119 NACATH lffl Matlow Adrieory CommlttN for Aeronautic • .

SIMPLE GRAPHICAL IOLUTJON or HEAT TRANI- FER AND EVAPORATION FROM IURFACE HEATa> TO PREVENT ICING . Vernon H . Gr • J . October 11152 . 19p. dtacr • . (NACA TN 2799) Equatlona e,q>re11lnc tlle beat tranlfer and evapora - tion from wetted 1urface1 di:rln& let prevention llave been 1lmpllfltd and recroiaped to permit eolutlo1111 bJ 1lmple 1raphlcal mun • . Worldns cbart1 for qlllck and accurate antl-l c ln& calculation • art aleo lncluded.

NACATNI041 Nalloul Adn801'J ComllllltN for All"OMllllc1.

ANALOGY 81:TWHN MAIi AND HIAT TRANIRll WffB TUUULSlff FUJIII. 1:dmlllld I. Calllpu.

October 1153. lip. dlqa 1, (NACA TN 3045) All .... , ... of comblaed llNl 111d .... lran • fer from • flat plate llal blen - • de lll 1111111 of Prandll'• atmpWled pllJ1lcal concept of tlle tllflMII• boundar, laJer. TIie Hllllll of tlle 11111,.,. allow lMl for con- dlUou of reuonablJ • man heat and mau traufer, tbl raUo of Ille mua- and lleal-tranaler coefflclenta la depelldenl on tlle lteynolda number of Ille boundlr, laJer, tile Prandll number of the medluan of dllf111lon, ud tlle lcllmldl n11111ber of tht dlffualnl Ollld ln the medium of cWf111lon. For the partlclllar cue of ..

waler enporallnl lnto alr, th• ratio of ma11- tranaJ,r coefflclent to hnt-lranafer coemclent la fOllftd lo be allptlJ 1re1ter Ulan 1111UJ.

NACA TN 3104 Nallonal Advlaory Commlllff for A1ronaut1c1.

EXPERIMENTAL INVESTIGATION OF 8UBLDIA- 110N Of ICE AT SUBSONIC AND SUPERSONIC SPEEDS AND ITS RELATION TO HEAT TRANSFIR.

WIilard D. Colu and Robtrt S. Ruggeri. March 19S4. 29p. dlagra. , photo. (NACA TN 3104) An uperlmtntal lnvut l pllon wa1 conducled lr, the 3.84- by 10-lnch tunntl to determine Ult mall trana- rer by 1ublimallon. heat tranarer, and 111.in friction for an Iced aurfact at 1ub10nlc and ••r10nlc 1peed1. The result • 1how that the Stanton n11mber1 or sublimation and heat lran,rer were lncrnilld 40 lo 50 percent for an Iced 1urr1ct or moderate roulh· neaa aa compared with lhoN obtained for I bare plate. For lee 1urracea or tqulvalent roupneu, the ralio of aublimatlon 10 htal-lranarer Stanton nu.mbera wu round 10 be 0.90. Subllmallon Stanton nwnber1 obtained at a Mach number or 1.3 1how1d no appreci- able deviation from lhoat obtained 11 1ub10nlc spetda . Subllmallon II a mean• of removlnc lee formall o na of apprerlable lhlckne11 la 10 1low aa o be of lilllt value In lhe de-Icing of aircraft at hllh alli1udea.

llB

NACA TN 110 National Ad,laory Comt 1t1N for Aerona11Uc1.

DPl:RIMENTAL DET&RMINATION or THSIUIAL

CONDUCTIVff'Y or LOW -DSNIITY ICE. Wlllard D.

Colee. March 11&1. llp. dialr1., ptloto, (NACA TN 310) TIie lllermal Conduc:ll'11J oi low-denaltJ k• llu bNII computed from data obtained ln an nperlaenlal lll• , .. upuon of tM heat tralllfer and man trauler bJ aubllmallon for an Iced aurface on a flat plate 111 a lllp-nloclty t&ncentlal air • lr.... TIM rH11lt1 are compared wttll data from Nftral aourcea OIi the tllermal conduct1'1tJ of pacllecl anow and aolld 11a&• Ice. TIie re1111t1 allow lood • 1reem111t wltll llle paclled-anow ,ah111, and tlle 111tenalon of llle curfta for packed • now to llle aolld Ice reslme lndtcatea lllat Ille c11ne • are appllcahle to Ice over the entire den • lty rans • .

l.23 NACA Tr , IJN National • d,taory CommlltH for Aeronautic • .

ICING Lu&IT AND WET~URFACE TEMHRATURE VARIATION FOR TWO AIRF'OIL SHAPES UNDEfi IIMULATED HIGH-SPEED FLIGHT CONDITIONS.

Willard D. Cole •. F1br1ary 1155. Up. diacra., pllotoa. (NACA TN 3398) .. • nrlatlon of wet- • 11rfAce tempent~r• and tlle conditlona tllat •Ill r1111lt 1,l ICl•fl'fl IIINCH for tusll•apeed ntpt tllrOIIIII clouda were lnveatlpled f!Jll)erlmentally . 1be r1111lla ue compared wUh calc11lattd value• obtalMd witll an analJtlcal IUCJlod.

The analytical reawt • wen pnerallJ conNrvaUve, stvlnc wet -111rfac1 temperaturu I° to 40 r lower tllan tlle e,q,erlment • and predictl.nc the formaUoo of

ice at nl1111 of ambient -atr temperature up to IJO r

llllh r than Iha • lll)erlmtnt •. TIie location of ua- lytlcally d termlned crlllcal rf' lou 01'.1 llle bodle • tor tht lnll I fo rmall n of Ice wu ell)lrlmentaU, 811b1tant Id .

124 NACAIUII lllrol . NallaMI AdYulor, CoamlltN, • MH ......

PULIMINAIIY UIULTI or Bl.AT TIIANlnR noM A ITATIONAJlT AJG> IIOTATIMO ILU.'901• DAL IPINNIJl . U. 10II Glalln. MIU& llU . la,.

diqr •. , pbolo. , I tabe. (NACA 1111 IUnl) ne COllftdlff .............. , ~ ..... ftre .. .

t•r1111lNd for an •11.peoldal aplllMr ol lO-ladl aul• mlllD diameter for botJI etllloll&r, ... ro&atllll aper- atlon. TIiie rup of co.dlllOM etildled lad .... UI'• .,.._•to ITI mUH per llov, l"OlalioMI .....

., to IIOO r,,m, and Ullln of .. tacll of Mro ... f".

ne nault1 ladlcat• Ul&l a~-_,, Mat u•auf•r oc- c•rr • 4 wlUI rotatlo11 of the 1plar.er . Trua1Uo11 from lamlnal' to t•rlMll•nt Dow occurr • d OYer a larp nap of lle,nolda 11111Dber1 pnmaru, becuN of ..,.

face f'Olll)ullu ol U.. aplllner.

, , Mhcellaneou1 NACA Preprint lo. 225 CORRELATION OF AIRFOIL ICE Jl'ORMATIONS AND THEIR AERODYNAMIC EFFECTS WITH IMPINGEMENT AND FLIGHT CONDITIONS Vernon H. Gray ABSTRACT An empirical equation is d v lop d by which chang sin drag coer- ticients due to ic torm:ition o~ an NACA 65AOo4 airfoil may be calcu- lated from known icing nd fli ht condition; this equation is then extended to includ available data for other airfoils up to 15-percent thickness ratio. 'l'he correlation v obtained pr1m&rily by use ot ice heights and ice an les me8 ~ ur don the 4-percent thick irtoil. The final equation, bov ver, do not include the ice measurement,, but relates change • in drag c~~!ficienta due to ice vith the tolloving var- i•ble1: icing time, air peed, air temperature, liquid-water content, cloud droplet-impin m nt rr ~ ciencies, airfoil ch~rd, angles of attack, and leading-edger diua-of-curvatur.

Cb&ngea in lift and pitching-mom nt coefficients due to ice on an II.CA 0011 airfoil ar als o r lat d to the corresponding changra in drag coefticient,. additional data on lift and itching-moment changes due to ice an liaited to th 65A004 airfoil, tor vhieb com lex trend• pre- clude a relation ahi vithin the • co o f thi pa r.

THE ICIIQ PRCILDI CURRIIIT STA'l'US OF IACA 'l'!CDIQUES AID RISEA.!ICB Un Ii. TOD Glahn ABSTRACT Icing of aircratt component• auch aa airfoil 1urface1 and engine- inlet 1y1te111 create• a 1eriou1 operational problem. Aircraft are nov capable of flying in icing cloud.a vithout difficulty. hoveTer, becauae re1earch by the NACA and other, ha1 provided the ~ngineering bt.sil for icing protection 1y1tema. Thia paper 1ummari1e1 1e11e of the techniques used in NACA program • to 1olve aircraft icing problems and indicates • .

the scope of the data available tor the design of aircraft icing pro- ection systems. The NACA Levis icing !acilitie, pecific test equip- ment and technique~ use~ in conducting test in icing vind tunnel •, and several icing instruments are discussed in detail.

NASA TECHNICAL MEMORANDUM X-54 700 (Alao NASA TM-82265) SOME CON S IDERATIONS OF THE NEED FOR ICING PROTECTION OF HIGH-SPEED. HIGH-ALT1TUDE AIRPLANES We von Glahn SUMMAR Y The icin · problems of high-seed, high- ltitude aircraft are confined to clim b e.nd let-down cond itions . The performance losse in icing can be minimized by t~e use of an icing protect on system t the ex ens of st ructural complexities and installed v ig bt . The elimination or airframe protbction syst ms tor aircraft sub ject. only to short icing encount rs a pears attractiv. rovided the perform- ance penalty due to icin i not xce ssi ve. ~1 a r considers the rf ormance , na:ty c u d by icin during climb in term ot r - duction in rt or cli and in range tor ircratt vithout airframe i c in 1 int n d t o hov only ord rs of magnitude lu

NACATN 4UO NIUanal AcMaory CommittN for AeroaauUca.

A FLIGHT EVALUATION AMD AMAI.1111 OF TD EFFECT or ICING CONDITIONI ON THE ZPG-r AlRSJDP. wuuam Lewi• and Porter J. Perlwla, Jr.

April 11151. Hp. dlqra., aaot,oa ., tab.

(NACA TN UlOl Teat ntpta conclacted bJ the U. I. N • Yybl • a&Ulllber al typical lclftl c011dlti001a are deacrlbed. The alr- llhlp operated ncceuMlJ bl all lclnl condlUoaa · - encountered, but tbe dealnblUtJ al Umlted protectloa for certain component• wu ladlcated. lclal la clouda wu conflned to wlrea ud 1111&11 compoDeata, but frNlinl raln and drlule p • .Alced aome lclAI on the ennlope :llao. Theoretical calculatiou an pre- Nnled which augHt tbat, wblle buardoua ictnc Ul free&Sns rain can occur under certala meteorolOllcal concliUma, tbe p!"obabilltJ of eacountertq tbeN COD• dlUona la very 1D1all 1n coutal areu and approad, ..

., zero 200 to 300 miles off•hore.

NASA TECHNICAL MEMORANDUM X-547OO (Also NASA TM-82266) ICING CONDITIONS TO BE EXPECTED IN THE OPERATION OF HIGH-SPEED, HIGH-ALTITUDE AIRPLANES William IA:!vis Sl!MMARY _ This paper considers the specific problems concerned with the prot- able frequency and severity of icing conditions to be expected in the operation of high-speed, high-altitude aircraft, as compared with the icing conditions encountered on older types of ai rcraft. There are two general aspects of this problem. The first phase of this discussion vi11 be concerned with the frequency and probably severity of icing conditions at high altitudes. High-altitude airplanes, however, must still climb and descend through the lower layers of the atmosphere where icing con- ditions are more frequent; therefore, the second phase of this discussion will deal with the effect of aerodynamic beating, due to high airspeed, on the icing potentialities of clouds encountered ~t low altitudes.

IACA Conterence on Aircratt Ice Protection June 26-27, 194 7 SUMMA.RY IACA'a latest research results were presented in 15 papers at the June 1947 Conterence on Aircratt Ice Prevention. ~e papers are compiled herein.

SOCIETY OF AUTOMOTIVE ENGINEERS PREPRINT NO. 424 HEAT REQUIREMENTS FOR ICE PREVENTION ON GAS-HEATED PROPELLERS

v. H. Gray

SUMMARY The investigation has established that teasible rates ot heated gas tlov can provide ample surface heating of propeller blades except at the leading edge, vhere complete ice prevention requires large rates of gas

fl o v, resu~ting in considerable vastage or heat elsevhere in the blade

an at the discharge nozzle. This waste beat can be reduced to a small fraction ot its original value by carefully designing the blade internal passage so that use is made of flow-confining partitions and metal fins attached at the blade leading edge.