Document
3 1176 00168 0678 1
NASA Technical Memorandum 81707
NAS A -TM-81707 19810010552
Survey o f Aircraft Icing Simulati o n Test
Facilities in North America
William Olsen
Lewis Research Center
Cleveland, Ohio 170_ REFEPL_ , L '_C , ,._
, " : ..7
I February 1981 . _!!'!,: ::i_ ,. :::i
SURVEYOF AIRCRAFT ICINGSIMULATION TEST FACILITIES IN NORTHAMERICA William Olsen National Aeronauticsand Space Administration Lewis Research Center Cleveland,Ohio SUMMARY i A surveywas made of the aircraft icing simulationfacilitiesin Nort h America. This was requestedof NASA by severalcommitteesconcernedwith Aircraft Icing. A similarsurvey of Europeanfacilitieshad already been reported in AGARD advisory report 127.
There are 12 wind tunnels, 28 engine test facilities,6 aircrafttankers _ and 14 low velocityfacilities,that can performvarious aircraft icing tests _ full or part time. The surveydeterminedt l _e locationand size of the facility, its speed and temperaturerange, icingcloud parameters,and the technicalperson to contact. These resultsare presented in tabularform.
The capabilitiesof each facility were estimatedby its technicalcontact person. The adequacyof these facilitiesfor various types of icing tests is discussed.
lY e !l - 19 o
INTRODUCTION Aircraft that fly low and slow and have small aero d ynamically critical surfaces are especiallysensitiveto icing. Helicoptersand generalavia- tion aircraft exactlyfit this worst case description. Significantactivity in the aircraft icingfield is expected because a large number of these aircraft are expecte d to be developedto fly into icing conditionsin the next few decades. Considerabledata (bothR&D and Certification)is re- quired before any aircraftcan be developedand certifiedas being able to fly safely through atomosphericicingconditions. Test flights in natural icingclouds are no great hardshipfor long range aircraft becausethey can ° rapidly fly the.greatdistancesand to the altitude required to find those elusive icing clouds. But obtainingflight data for the helicopterand GA aircraft in natural icing can be prohibitively expensiveand time consuming becauseof their range and altitude limitations. In order to reduce our reliance upon natural icing flightsfor short range aircraft,improvements appear to be needed in the Aircraft Icing SimulationFacilitiesand in the analyticalmodels for icing and its effects. The first step in this im- provementprocess is to determinethe capabilitiesand limitations of all of the existing icing simulationfacilities.
NASA was requestedto survey the capabilities of the facilitiesin North America that can do aircraft icing simulationtests. The survey was re- quested of NASA by the Standing Committeeon Icing, which is jointly spon- sored by NASA, FAA and NOAA; similiarrequestshave also been made by the military servicesand AGARD. European icingfacilitieswere not included because they have already been surveyed (ref. i).
The reasonsfor the survey are to: 1. Assist the icing researchcom- munity in determingthe adequacyof the presentmix of icingtest facilities for all types of aircraft,2. Make it easier for a potentialfacility user to select and contact the icing facility that is appropriate for his test requirements,and 3. Help facilitymanagers evaluate and improvetheir facility.
This paperincludes a short descriptionof the various types of facili- ties, a detailed listingof the capabilities of each facility,and some discussionand evaluationof these capabilities. The capabilities of the facilitiesare presented in tabularform. The capabilitiesof each facility are the opinion of the tecnnicalpeople working with that facility. Based upon the informationin t h e tables and additionalinformation, cursory evaluationsare then made of the adequacyof the existing facilitiesfor the various types of icing tests. Some additionalcomments are also made about icing cloud instruments.
DISCUSSIONOF FACILITIES The icingenvironmentthat an aircraft and its componentsmust operate in is describedin this section. Then the various types of icingfacili- ties, . andthe tasks they are used for, are briefly described. Following that, the capabilities of the icingfacilitiesin North America are briefly discussedalong with additionalinformation.
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Icing EnvironmentRequirements Aircraft flying throughclouds below about 8,000 meters can be subject tothe formationof ice (icing)on critical surfaces,which can cause seri- ous losses in performancean d damage,and even a crash. The ice forms from th e sm all s u pe rc o ole O dro p let s i n these cloud s (IcingCloud Environ m ent, ICE). At low altitudes,large supercooleddroplets (FreezingRain, FR) also result in icing. The effect of snow, and ice particlesand ice chunks on the aircraft (especiallythe e n gine)must also be considered. In ad d ition, there is a concern about mixtures of the above conditions. The range of atmosphericparametersfor ICE, that are used for design and certification testing of transportaircraft,are defined in Federal AviationRegulation (FAR) part 25, appendixC (ref. 2). These ranges of temperature,liquid " water content and d rop size, at various altitudesfor Stratiform(layer) and Cumuliformclouds, are shown as envelopeson figure 1. These envelopes define the maximum likely ranges of these parametersthat woul d Occur in nature (i.e., 9_.9 percent of the observationsin nature lie wit h in these envelopes). The aircraftmanufacturer must design his aircraft to cope Wit h every combinationof the parametersrepresentedby the envelopes,along with the mission of the aircraft (e.g.,altitude,airspeed and exposure time to the ICE). From these considerations he must determinethe specific ICE conditionsthat result in the most severe icingon each aircraftcomponent (e.g.,wings, engine inlet,etc.). These discreteconditionsbecome the design and test conditionsfor icing tests of the aircraft,its components an d icingprotectionsSystems. Although desirable,an icing facility doesn°t have to operateover the entire range of the entire FAR 25 envelopes in order to do meaningfulR&D tests an d certification tests. Furthermore, some aircraftcan't possibly encounterthe fu l l range of conditions ' ;in d i- cated by figure 1. For example, the helicopterhas a limitedaltitude capabilitywhich makes high levels of LWC extremelyunlikely;indeed, refer- ence 3 suggeststhat a truncationof the FAR 25 envelopesshould be use d for he l icopters. At the ot h er extreme,engines are designed an d teste d for the whole FAR 25 envelope (ref. 4), largelybecausethey are used in a variety of aircraft. As a minimum goal, all facilitiesshould be able to produce 20 micron droplets for any icing test of a full scale aircraft or component.
Types of Icing Facilitiesand Their Uses The types of icing test facilitiesand the types of icing tests are listed below.
FACILITIESFOR ICING TESTS Natural icing flights Icing simulationfacilities: A. Wind tunnels B. Engine test facilities a. Free jet b. Direct connect C. Low velocityfacilities D. Flight tests with tankers Other icing simulationtechniques TYPESOF ICINGTESTS Certification and R&D testsfor: Engines Instruments Fixed wing aircraft Helicopters Componentsof the above (including: ice protectionsystems, wings, etc.)
General research and technology Natural icing flights.- Aircraft manufacturersoften fly their aircraft in a broad range of natural icingcon d itions in order to obtain certifica- tion by the FAA as being able to fly safely in icing conditions. This is an expensiveundertaking. It is reasonablefor long range aircraft,because they can fly greatdistances to fin a those elusive icing clou d s that are hard to find when you want them. But for short range aircraft (e.g., h eli- copters and civil aviation aircraft) a test program involvingnatural icing is all but prohibitively expensive,time consuming and uncertain(refs. 5 and 6). In any event natural icing flight tests are not discussedin this paper, which is devoted entirely to Icing SimulationFacilities.
Icing simulationfacilities.- Research and Developmentan d Technology types of tests, and much certification must largely be accomplishedin one or more of the varied types of Icing SimulationFacilities. The four gen- eral types of simulationfacilitiesand their major variationsare schemati- cally sketchedon figures 2(A) to (D). T h e primarydifferencesbetweeneach type of facility are in their geometry,airspeed,and in the types of tests they are used for. The general operationof all is similiar;the next para- graph describestheir operation in a generalway.
In all icing simulationfacilities,the test aircraftor component is tested in a cold airstreamwhich contains a smaller icing cloud. The icing cloud is made up of either supercooleddroplets,which freeze when they strike the test surface,or ice particles. The Icing Cloud Environment (ICE) is made up of very small supercooleddroplets (10 to 50 micron diameters)which are sprayedinto the cold airstreamby specialnozzles (generallyhigh pressure,hot air and water). As the dropletstravel in the cold airstreamthey cool well below the freezingtemperaturewithout freezing (i.e., they supercool). Differentnozzlesor other devices are used to generate the larger droplets of freezingrain (FR) and the solid ice particles(SI) respectively. The cold airstreamis either cold ambient air or else it is cooled wholly (or in part) by a large refrigerationsystem.
Other icing simulationtechniques.- Aerodynamicperformancepenalties caused by ice are traditional l y ascertainedby flying the aircraftwith "plastic ice" shapes attachedto the wings and tail surfacesetc. This would be more difficaltto do safely with helicopterrotors. Analytical simulations are also used to a large extent. Aircraft certificationis often based upon the similiarityof a new aircraftor componentto one already certified. These methods are again not discussed in this paper; only icing simulationfacilitiesare discusse d .
Descriptionof Survey The surveywas limitedto those existingNorth American facilitiesthat have an icing simulationcapability. In other words, they producesuper- , cooled droplets (ICE and / or FR) in a cold moving air stream. Future icing simulationfacilitiesare also include a if they are funded or seriouslypro- posed. It is believedthat all of the facilitieswith ICE capabilityhave been included,but some low velocityfacilitieswith FR capabilitymay have been missed. .
The facilitiessurveyed an d their capabilitiesare listed in tables A to D, one table for each of the four types of facilitiesdescribedon figures 2(A) to (D). The capabilitiesof the individualfacilitieswere estimated by the technicalcontact person for that facility. Preliminarytables were completedby phone; later, the applicabletechnicalperson for each facility was sent a copy of the tables to check the entriesfor his facility. The numbers listed in the table are single point approximations by him of the operatingcurves of that facility. Many of the capabilities were truncated so that comparisonswould not be made betweenfacilitieson the basis of unimportantexcess capabilities for aircrafticing tests.
Descriptionand Capabilitiesof Icing SimulationFacilities As noted before, the primarydifferencesbetween the varioustypes of facilitiesare in their geometry,airspeedand in the types of tests run.
Each type of facility is now discussedalong with some comments about the capabilitiesof some individualfacilities.
Wind tunnels.- The test section leg of a typical icingwind tunnel is schematically sketched in figure 2(A). Table A lists the icingwind tunnels in North America. Most are close d loop wind tunnels;one is a Free Jet (entry A-5) that is listed in this table becauseit primarilydoes wind tun- nel type of work. There are ten (10) tunnelsthat are active now; a very large wind tunnel has been proposed (A-lb),but facilities(A-4a) and (A-4b) have recentlybeen remove d from the icingfacility rolls. The test sections of the existing tunnels range from 1.8x2.7meters for the largest(A-la) to 0.15 meters for the smallest (A-6a). The highestvelocityfor the larger existing tunnels is 470 km / hr; one small facility (A-5) can achieve M = 0.8. Most of the existing tunnels are limitedto sea level altitudes, except for the smallerones (A-5 and A-6b). All but (A-9) produce the Icing Cloud Environment(ICE) of adequatelysmall supercooleddroplets,including the 20 micron minimum goal. Only a few of the existing tunnels producethe larger droplets of freezingrain; none pro d ucesolid ice particles(SI).
None produceSnow (S) either. It shoul d be pointedout that NRC researchers found that the best snow simulationwas made by "shovelingin" loosely packed natural snow. The LWC range, and the size of the uniform icing cloud are generallyadequate. All of these facilitieshave refrigerationso that they can be run all year; in addition,most are dedicate d to full time icing testing. The existingwind tunnels are ideallysuited for researchan a developmenttype tests. Certification testing at the most severe icing conditionscan often be performed. But none of the wind tunnels can cover the entire FAR 25 envelope,or the entire altitudeand velocityrange of test aircraft. Furthermore,the tunnels are relativelysmall so that only co m ponent so f th e aircraft are usually tested (e.g., inlets,tai l section etc.). Helicopterrotors are s imply too large. Icing scaling laws are often u s ed t o converttunnel re s ults to the s! z e, airspee d an d altitudeof the test aircraft(ref. 7), an d to accountfor the deficienciesin the LWC and drop size of the cloud. Unfortunately, these scaling laws have not been adquatelyverified experimentally.
Engine test facilities.- Tab l e B in d icatesthat there are 28 active engine test facilitiest h at can d o engine icing tests; in a d dition,a large engine test facility (B-lc) is plannedfor 19B3. These are a l l engine test facilitiesthat do icing tests on a test engine as part of the test program; icing tests accpuntfor about 10 percentof the test programfor each engine.
There are two basic types of engine test faci l ities: the Free Jet (fig.
2-B(a)) and the Direct Connect (fig. 2-B(b)). Many of the engine test facilitiescan be configuredto be run either way. In the Free Jet mo d e, the airstreamfrom the nozzle (i.e. the jet) passes around and through the engine. In the Direct Connectmode, the nozzle is extended to the engine inlet so that all of the airstreampasses throughthe engine.
A number of these faci l itiesare large and can attain high airspeedsand altitudes(e.g., B-la, B-lc, B-6b, and B-6c). The largestof the high speed Free Jets has a five foot diameter nozzle (B-l(b)). There is also a very large Free Jet (B-3) but it is limitedto very low velocities.
The largestof the present engine facilitiesare too sma ll to han d le very largejet engines or large turboprops. Facilitiesthat can presently handle G I A propellerengines are limited in number (e.g., B-9). This prob- l em is discussedin more detail in a later section.
All facilitiesproduce an icingcloud environment(ICE). Only a few of the facilitiesproduce solid ice (SI) particlesnone producesnow. Most have refrigeration so that they can be run all year. Comparinga l l the capabilitiesof the Engine Test Facilitieslisted in table B with the Certification requirements,indicatesthat Certification tests can be performedfor engines in most of these facilitiesover the entire FAR 25 certification envelope. T h e LWC in the cloud is reporte d to be a d equately uniform acrossmost of the flow.
The Free Jet can be used for many icing experimentsthat would normally be performedin wind tunnels, especial l ythose with test surfacesthat are short enough axiallyto stay within the potentialcore of the jet (cone shaped region of uniform velocity and low turbulencethat is about four noz- zle diameterslong). The air speed and altitudecapabilityof some of these facilities(e.g. B-lb) are excellent.
Low velocityfacilities.- There are 14 existingfacilitieslisted on table C. One wi l l be mothballed by 1985 (C-1). All operate at a low veloc- ity. All have FR capability;the first seven (7) can also produce the ICE.
Most of thesefacilitiesare used for typicalcold room tests of equipment and personnelin a ground level environment(cold air at low velocity);air- craft icingtests are a small fraction of theirwork load. Most of the facilitiesare large refrigeratedcold rooms, where the test aircraftor component is tied down on the floor and subjectedto a fan blown spray (see fig. 2-C(a)). One of these refrigerated facilities(C-3a) is largeenough to permit a full scale aircraft to be tested with partial immersionin an icingcloud.
Figure 2-C(b) describesthe unique HelicopterSpray Rig (C-1),which is located near Ottawa,Canada. In this case the test Helicopterhovers in the wind blown spray. A large engine test facility ( C-2) has been listed h ere in a dd iti o n t o being liste d in table B. On Mt. Was h ington,e q ui p ment is tied d own an d subjectto s evere natural icingcon d itions(C-5). The re- frigeratedcold ro o m s can perf o rm icin_tests all year, whereas f acilities C-I, C-2, and C-5 are e ss entiallylimitedto winter operation. The LWC and drop size is adequate for ICE or FR tests (whicheveris applicablefor a given facility).
Tankers for flight tests. - There are six (6) tankers listed in table D; one of these (D-5) has just been added, and (D-ib) is not yet in operation.
Figure 2(D) describesthe HISS tanker (D-2) an d its test helicopter;all other tanker facilitiesare fixed wing aircraft. There are differencesin the shape, size.and locationof the spraymanifold. Icing tests can be run wit h most fixed wing aircraft in any season by merely flying at the altitude where the desired temperatureoccurs. The limitedaltitude capabilityof helicoptersan d some G / A aircraft limits the icing test season to the winter season. Most of the tankersare dedicate d to do icing tests full time.
There have been many problemswith these facilities. One of the most seri- ous was large droplets in the spray. Excessivelylarge droplets (larger than 100 microns) are usually easy to spot because the entire unheated nose of the aircraftwill ice up, whereas the small droplets in natural icing will only cause the small stagnationregion of the unheatedblunt nose to accumulateice. Tests were recentlyperformedon the spray nozzlesfrom the Army HISS and Air Force tankers in the NASA IRT (A-la). The presentmili- tary tanker nozzleswere found to producedroplets that were 2 to 20 times too large, relative to the 20 micron goal. Fortunately,some of t h e nozzles tested producedthe desired droplet size at reasonableair and water pres- sures (ref. 8). T h erefore,the droplet problemof the entire tanker fleet is on its way to a solution. The icing cloud from all of these tankers tends to be small and non-uniform, with the test aircraftweaving about within the icing cloud; this causes the LWC to vary with time. To partially accountfor this difficultya time averagedmeasurementof the LWC (e.g.,an ice accretionmeasurement)should be made at the locationwhere the critical ice accretionoccurs. Another problem is that most of these tankers are not readily available. The Flight systemstanker (D-5) is a recent welcomed addition to the fleet, because it is availablefor hire to all.
Availabilityand Cost Availabilityand chargesvary greatly among facilities,an d from test to test. The best recommendation is to first use the tables to select the facilitiesthat might fit your needs, then discussyour particulartest with the technicalcontact person (also note d in the tables) for each of those facilities.
CURSORYEVALUATIONOF ICINGFACILITIES The adequacy o f existing Icing SimulationFacilities,in performingthe varioustypes of icingtests listed in table 2, is judged in this section.
Deficienciesare cited and some short term correctivemeasures are briefly discussed. These cursoryevaluationsare based upon: the data in the tables, additionalinformationand opinionsfrom the technicalpeople work- ing with the facilities,and the partialevaluationsmade in references9 and 10.
Facilitiesto test instrumentation. - There are severalexcellent small governmentand company facilitiesfor R&D and certificationtests or icing instrumentation, (e.g.,A-4b, A-5, A-3, and A-7). The first two have the advantageof being able to cover a broad range of air speed, altitude and cloud conditions. In addition,the larger facilitiesoften can inexpensive- ly run instrumentation tests along with anothertest.
EnBine test facilities.- Table B indicatesthat there are many engine test facilitiesthat can d o icing tests, and most of these have excellent capabilitiesfor testing engines over the whole FAR 25 envelope. Neverthe- less there are some apparent deficiencies. Column 3 on table B indicates that there are xery few facilitiesthat can generateengine- a amaging-solid ice particles(from hail and snow to ice chunks). Snow, which is a problem for some inlets,can not be simulated in any facility. A facility is neede d to test very large jet engines. This need should be satisfiedby the ASTF (see B-lc), which is planned to be built at AEDC in i983. The engine test facilitiesthat exist today are nearly all sizedfor turbofanand turbojet engines. A turbopropor G / A propellerenginewould be difficultto test in most of these facilitiesbecause of the prop size and the very large airflow that must be cooled in these once through-engine facilities. Smaller turbopropscould be handled by some of the facilities(e.g., B-9, outdoor mode; B-3; and 3 meter diameter prop engines have been run in the diffuser of A-l). There is no facilityfor largehigh speed turboprops;howeverthe one proposed by NASA (A-lb) could again handle the task.
Facilitiesfor fixed wind aircraft.- Certification flight tests in natural icing are expensive but reasonablefor long range aircraftthat can fly to an area and altitu d ewhere icing is likely. But for short range aircraft (e.g.General Aviation),such flights are prohibitively expensive.
All fixed wing aircraftrequire simulationfacilitiesfor R&D icing testing and some certificationtesting. Short range aircraftuse simulation facilities,even for some of their certification testing. The best mix of icingfacilitiesfor the near term appear to be the fixe d wing tankers (tableD) and the three ground facilitiesas outlinedbelow.
RECOMMENDEDPRIMARYFACILITIESFOR FIXED WING AIRCRAFT (NEARTERM) Flight Tests t NaturalIcing Increased Long range aircraft: reasonablefor certification tests cost Short range: only minimal programs affordable Flight tankers Ground Tests Full scale componentsat high speeds: (B-la) Full scale aircraft at very low speeds: (C-3a) Full scale componentsat moderate speeds: (A-l) and (A-2) Tanker aircraftneed technicalimprovements(alreadydiscussed),addi- tional experimentalverification of the validity of this testingtechnique, and greateravailability. Three ground facilitiesare requiredfor R&D tests because no one existing facilitycovers the required range of size, air speedand altitude. For icing testingof full scale aircraft (but at very low velocities),a good choice is the Eglin cold rooms (C-3a). Full scale aircraftcomponents(e.g.,wings, inlets,etc.) can be tested at . moderate speeds in the NASA IRT (A-la) or the smaller tunnel at Lockheed (A-2). Most severe icing conditionsoccur at low speeds and low altitudes, where these facilitiesoperate. But if icing tests of full scale aircraft componentsare required at high speed and / or high altitude,then the AEDC free jet (B-lb).should be considered. It should be pointed out that the large wind tunnel rehabilitation proposed by NASA (A-Ib) can handle all three requirementsof large size, high speed and high altitude;but this facility wouldn't be availableuntil 1987. Scaling laws are often used to compensatefor limitationsin the speed, altitudeor size of a facility,or limitationsin the icingcloud produced;however, the icing scalinglaws have not been adequatelyverifiedexperimentally.
Facilitiesfor helicopters. - Performingflight tests on helicoptersin natural icing is extremelycostly,because the limitedrange and altitudeof the helicoptermakes it difficultto find icing conditions. Thereforeicing simulationfacilitiesare needed for the bulkof the icing tests; perhaps even includingcertification tests (ref. 5).
The engine, inlet and the fuselage componentscan be readilyhandled by existing engine test facilitiesand by the icing facilitiesused for fixed wing aircraft. The effect of the rotor can often be handledby using a reasonableangle of attack.
This is not the case for the rotor. Icing test facilitiesfor the main rotor are not readily available,mainly becauseof its great size (12 to 18 meter diameter). Another difficultyis that the ice on the blades is subject to velocitiesranging from M = 0 to 0.8, and to largecentrifugal forces.
A number of icing simulationfacilitiesand test rigs have been proposed and used to do rotor icing testing in the near term; these are listedand described in the followingtable in their approximateorder of: increasing experimentalcontrol and data confidence,and decreasingcost, but decreas- ing flight icing simulationaccuracy.
L TABL EOF RO TO RICINGTESTMETHODSIN NORTHAMERICA(NEARTERM) Method Types of tests Problems A. Natura l icing flights Helicopterf l ight tests Winter only. Har d to find _esired Ce.g., a l l companies) icingcon d itions,so test programs expensiveand long before you get data of high confi a ence.
B. HISS Tanker (US army) Helicopterflight tests in spray Winter on l y. Somewhat less expen- cloud sive than naturalflights. It is assumed that the drop size an d c l oud size, etc. are made accept- able. Nee d s verification.
C. Ottawa spray rig Helicopterflight tests at very Winter only. Close d after 1985.
(NRC) low forward speeds in ground Relativelyinexpensive, relative l y leve l spraycloud good control of conditions. Ques- tions raised about simulationand using results for higher forwar d spee d s.Needs verification.
D. Large cold room Helicoptertie down tests at near All year. More expensivethan C.
(Eglin AFB) zero forward speeds Many practicalproblems surface d when it was tried.
E. Scale model rotor in Ice accretionand its affecton Scaling laws for icinghave not icing wind tunnel rotor performance. Icing scal- been a d equatelyverifiedexper- (NASA IRT) ing laws suggestthat this imentally.Sma ll estdrop sizes shou l dwork. presentlyproduceablepermit mode l s no smaller than 1 / 5 scale.
Deicing systemscan not be scaled d own readily. Needs verification.
F. Rotor blade segment Main rotor blade segmmentof If you match G forces, the blade or tai l rotor on a nearly full scale chord on velocitiesare very low. Needs rotating rig in icing rotatingrig to test deicing verification. Small tai l rotors tunnel (NASA IRT) system operationan d shedding shoul d be c l osely simulated.
at conservativeconditions.
Also full to nearly full scale tail rotors G. Osci l latingor fixed Full scale blade segmentteste d The maximum airspeedof the IRT is airfoil in icing tunnel with periodicor fixed ang l e of only M = 0.4, which is too low to (NASA IRT) attack (for ice accretion,aero- determineresults in the critical performanceand deicing system outer ha]f of the rotor. No G performance)in the absenceof G forces,thereforesheddingnot forces, but with b l ade ben d ing true but conservative. Needs and twisting verification.
Certificationtypes of tests tend to be performedon the facilities listed on the top half of the table, whereas R&D tests tend to be accom- plished on the lowerhalf. But there is considerableuncertainty;verifica- tion tests are needed in order to determinewhere these simulationfacili- ties adequatelysimulatenatural icing on the rotor at the variousflight conditions. For example,the HISS tanker - until recently- generatedicing clouds with droplets that were about 10 times larger than those of natural icing (ICE); as a consequencethe icing resultswere closer to those pro- duced by freezingrain (FR). The new spray nozzlesfor the HISS now produce the correct20 micron drop size (ref. 8).
The Ottawa spray rig (B in the above table) is a valuablefacilitY;but it may not be availableafter 1985. It is also limitedto near-zerospeeds, althoughmany users have tried to extrapolatetheir results to cruising speeds with mixed success.
The dynamic and aerodynamicdegradationof a rotor in icingcould be determinedin principleon a model rotor in an icingwind tunnel. Unfortu- nately icing tests of model rotors suffer from the followingdifficulties.
First, existing tunnels are too small. Figure 3 indicatesthat the largest models that can be tested in the largestwind tunnel (A-la) with proper aerodynamicswould be i 1 6 th to 1 / 12 th scale models. These models would require smallerdroplets,for proper scaling,than can made with present nozzles. Furthermore,these models would have to be built from scratchat very nigh cost, because the model rotors used by the helicoptercompanies are larger. The proposed largewind tunnel (A-ib) would be large enough to avoid this difficultybut this will not be availableuntil 1987. And final- ly, the icing scaling laws have not been validatedexperimentally.
The test rigs for rotor icing are unable to simulateall the forces acting on the accreted ice. Specifically,a rotatingblade segment (F in the above table) will have very low blade velocitiesif the G forces are matched. Thus any test of a deicer systemwill be conservativeand will require analysis in order to relate the results to the actual conditionson a full scale rotor. The oscillatingblade rig (G in the above table) also gives a conservativesimulation,primarilybecause no G forces are Present.
The main purpose, of the test rigs (F and G) are in the developmentof rotor icing and deicing analyses,and for conservative developmenttests.
The facilitiesand test rigs in the above table are, or will be, avail- able soon. Two major facilitiesto do icing tests on full scale rotors have been seriouslyproposedfor the long term. One is an improvedtanker using either a large helicopteror a large slow speed fixed wing transport. The other is a very large slow speed test sectionfor facility (A-ib).
The recent loss of the small high speedwind tunnel of NRC (A-4b) is a serious handicaptoward acquiringvital data on the aerodynamicdegradation caused by icing on 2D rotor airfoils. A replacementfor this facility is needed.
APPENDIX - ICING CLOUD MEASUREMENTS In the course of making this survey of facilities,a number of concerns about measurementswere brought out, which will be brieflydescribed in this section. They are: drople_ size measurement s ,the need for comparable liquid water contents (LWC) in all facilities,the uniformityof the LWC and drop size across the icing spray cloud, and the relativehumidity and tem- perature of the air within the cloud.
LWC standard.- The survey broug h tout the fact that it is difficultto compare icing resultsfrom differentfacilities. Part of the reason for this difficulty.isthat the accuracyof LWC instrumentsis often only about •20 percent. Another reason is that there is no standard instrumentthat can be used in all facilities. It has been suggestedthat a thin blade (0.32 cm thick x 1.9 cm chord) be used as an interim standardbecause it is adequatelyaccurateover a large range of con d itions,and easy and inexpen- sive to make and use. The blade has been describedand investigatedin detail by Stallabrass(ref. 11). The blade is exposed to the cloud for only 30 seconds and the air is cold (<-12 ° C) in order to avoid thermal problems (ref. 11). The thicknessof the ice accretionon the thin edge is measured by a micrometer;the LWC is then determinedby a simplecalculation. With such a common standard,the LWC calibrationcurves for all facilitiesand LWC instruments could be inexpensively made consistent. A more accurate but more expensivestandardwould be a thin rotatingcylinder (0.32 cm diam rod) that is exposed to the cloud for a short time.
Uniformityof LWC and drop size.- In all simulationfacilities,it is usually desirab l eto have a uniform LWC and drop size across the cloud.
With reasonablecare in the design and maintainance of spray nozzle arrays, the drop size should be reasonablyuniform,especiallywith small droplets.
Achievinguniformityof the LWC is inherentlymore difficult. Becauseof turbulentmixing, the sprays from each nozzle undulate so that the accumula- tion of ice at a given point is due to the time varyingLWC from many noz- zles. In tanker tests, the test aircraftalso undulateswithin the spray cloud. Forturnately,the ice build up is a time averagingprocess,which moderates this difficulty. Even in the well controlledwind tunnels, a few spray nozzlesmust be moved from time to time in order to keep the LWC across the cloudreasonably uniform. It proved to be difficultduring the surveyto quantitatively establishhow uniformeach facility'scloud was.
Part of the reason for, this is that there is no standardfor uniformity. A practicaldefinitionof the uniform region would be wherever the time aver- age LWC was within + / - 20 percent of the LWC at the center of the cloud.
The uniformityof ground facility sprays is usuallydeterminedby the uni- formity of the ice accretionon an array of cylinders. The d eterminationis based upon visual insPectionor a measurementof the uniformityof the mass of ice accreted.
Droplet size. - A cursory look at column 12 in tables A through D indi- cates that the volume-mediandrop size is measured by a varietyof instru- ments, ranging from the "tried-and-true" older methods (e.g., rotating cylinders and oil slide) to modern methods (e.g., laser spectrometers and laser holographs). The relative accuracyand practicality of these instru- ments is still being debated. The consensusof users (verbaland reports) indicatesthat the accuracyof the modern instrumentsappear to be + / - 3 to 6 microns, for the drop sizes typical of ICE (refs. 12 and 13). Most of the o l d instrumentscan't give real time results, and they may not be quite as accurateas the modern instruments; on the other hand, they are far less expensiveto use if the amount of the data is modest. Two other points to consider are: How often must the drop size be measured,and what accuracy is required. For example, a 5 micron error might be acceptablein a Certificationtest requiring20 microns. In an icing simulationfacility, drop size measurementsneed not be made very often. Measurementshave indi- cated that the spray in the NASA IRT has producedthe same drop size for more than 20 years with only minimal maintenanceand demineralized water.
" Relative humidity and temperature of the air in the spray cloud. - Accurate measurements of the relative humidity and temperature of Lhe air inside of the spray cloud are extremely difficult. The slightest amount of moisture will drive the relative humidity from 0 to 100 percent at the low air temperature of icing tests. Often, the best approach is to measure the conditions outside of the cloud and use a heat balance to calculate (ref. 13) the relative humidity of the air in between the droplets of the spray cloud.
Recommendation. - A comprehensive experimental comparison of LWC, tem- perature, drop size and relative humidity instruments should be made in an icing tunnel, where the spray cloud is relatively repeatable. Such a test will determine the relative accuracy (not absolute accuracy) of the various instruments (both modern and old style) and their limitations for various app l ications.
Along these lines it is also recommendedthat one small icing facility be used as the standard reference cloud, where instruments and their cali- brations could me occasionally checked out. This would help standardize measurements made in ground facilities and in flight. This approach takes advantage of the repeatability of spray clouds in ground facilities, and admits that there may never be a cloud measurement whose accuracy is abso- lutely known.
REFERE NCES 1. Pierre,M.; and Vaucherett,X.: Icing Test Facilitiesand Test Tech- niques. Aircraft Icing, AGARD Advisory Report 127, 1977,pp 6-2 to 6-5.
2. AirworthinessStandards,TransportCategoryAirplane. FederalAviation Regulationpart 25, Appendix C.
3. Werner, J. B., The Developmentof an Advanced Anti-lcing / Deicing Capabilityfor U.S. Army Helicopters, Vol. 1: Design Criteria and TechnologyConsider a tions, USAAMRDL-TR-75-34A, 1975.
4. Pfeifer, G. D.; and Maier, G. P.: EngineeringSummary of Powerplant IcingTechnical Data. PWA-5522,Pratt and WhitneyAircraft Group, 1977. (FA K -RD-77-76, AD-A045087.)
5. Minutes of Session V HelicopterIcing Syn_oosium, Ministry of Defense, London,Nov. 1978, pp. 335-339.
6. Newton, D.: A Review of the IcingSituationfrom the Standpointof GeneralAviation,Aircraft IcingNASA CP-2086,FAA-RD-78-109,1979, pp. 31-38.
7. Hauger, H. H.; and Englar,K. G.: Analysis of Model Testing in an Icing wind Tunnel. SM 14993, DouglasAircraft Co., 1954.
8. Belte, D. and Ferrel,K. R.: HelicopterIcing Spray System. American HelicopterSociety Paper 80-52,May, 1980.
9. Beheim,M.: Summary Report-lcing Research and Facility Committee,Air- craft Icing. NASA CP-2086,FAA-RD-78-109, 1979, pp. 121-i28.
10. Tests, Aircraft Ice Protection,FAA Advisory Circular,AC-20-73,1971, Chapter 4, pp. 19-27.
11. Stallabrass,J. R.: An Appraisalof the Single Rotating CylinderMethod of Liquid Water ContentMeasurement. Report LTR-LT-92,National Research CouncilCanada, 1978, Icing blademethod on Pages 10-18.
12. Jeck, R.: Performanceof the PMS AxiallyScatteringSpectrometer Probe, Aerosol Measurement,D. A. Lundgren,ed., Universityof Florida Press, 1979, pp. 294-311.
13. Hunt, J.: Engine Icing Measurement C_pabilitiesat A EDC. Icing Testing for Aircraft EnginesAGARD CP-236,1978, pp. 6-1 to 6-14.
14. Willbanks,C. F.; Schultz, R. J.: AnalyticalStudy of Icing Simulation for Turbine Engines in Altitude Test Cells. ARO-ETF-TR-73-59, Arnold Air Force Station, 1973. (AEDC-TR-73-144, AD770069.)
ABBREVIATIONS, AND FOOTNOTESFOR TABLES aTypes of icing and anti-deicing tests run: CPU - comp.lete propulsion unit; EDC - engine direct connect; FSC . full-scaleaircraftcomponent (includingwing, tail, fuselage,windshield,stores,gear, etc.); MS = model scale tests and instrumentation; IA = ice adhesion;CP = cloud physics;R = rotating experiments(e.g., helicopterrotor models and pro- pellers);G = ground transportand installations in freezing rain; FS = full-scaleaircraft;FLT = flight tests of aircraft;I = inlets with suction;P = complete propellerengines; H = human physiological experi- - ments.
bwhether simulated: ICE : icing cloud environment; SI : solid ice parti- cles; FR = freezing rain; R = rain; N = natural icing; S = snow.
Cparameter ranges vary with conditions; request operating envelopes from contact person.
dModification to do this has been seriouslyproposed.
eTests in progress to extend these limits.
C AP A B ILI T I E S O F I CING SIMULATIO NT EST F ACILITI ES IN N OR T H AMER I CA [ CapabiLit i es esti m ated by technical c o ntact person for each fac i l i ty. ] A. WIND TUNNELS Fa - Facility name Types o f Weather "l _ pe o f S i ze (see sketches), m Range of 'parameters used in icing t e sts c Instru m e n ts Technical Test C o mme n t c i li ty (Loca li oo) ici n g aim u - facility used for person to sea- n o. tes ts run hted Test Un i form Air speed, Mla. total A HI - LWC _ V ol. med. loc al drop co n tact son chamber icing cloud k m / hr air tern- rud e, g / m drop size and perature m size , (LWC) ( a ) (b ) ° c _m A-1 NA S A - Lewis Research Cent e r (Clevela n d, OH) (a) IRT FSC , I ICE, Wind H = 1.8 hu = 0.9 I0 to 470 - 3 0 0 e 0 .5 to ell to 25 Rot. cycls, andv ar - J. Re in mann Al l Moderni z ati o n M S , R , FH d tunne l W = 2.7 w u = 1.5 3.0 l ons m odernin s tru- (216)433-4000 year nearly complete IA, pd L = 6 m ents (rot. cyl.)
(b ) AW T - R e habilita ti on FSC, I , I I CE FR [ W in d D = 6 du = 4.5 I 0 to M = 1.O -30 0 t o 0.2 to 1 O to 50+ Various m odern J. Yuskn All P ro posed f o r 1987 MS, R , ! SI ' ' tunnel 15 000 3. (nozzl e s i nst rum e n t s (21 6) 433 - 4000 y ea r CPU, G, P D = 1 4 U P T O 9 5 changed) : A-2 Lockheed MS , FSC , ICE Wind H = 1.2 hu = 0 .6 9 0 to 34 0 - 2 0 0 0 .7 t o 1 0 to 2 5 Ro t. eyls. B. Ro b i ns o n All (Burbank, CA) tunnel W = 0 .8 wu = 0 .3 4. 0 (r o t. cy l .) (213)847 - 61 2 1 ! year A-3 Hoe i ng l V _ , FSC, I ICE Wind H = 0 .5 hu= 0 .4 18 0 to37 0 -3 0 0 0 .3 to 1 0to S 0 Ro t. cycls. , o il R. Wilder All (Se a ttle , WA) tunnel W = 0 .4 w u = 0 .3 5. 0 (nozz l es slide (a m . cyl.) ( 2 0 6)34 2 -477 6 y ea r L = 0 .9 c ha nged) (a) Large T us nel _ / _ _ __ (b) H i gh Speed MS , F S C ICE W in d H=W =0.3 hu =wu = O . 25 90 to M= 0.8 - 30 0 to 0 .2 to 15 t o 25 Oil s ti de ( ru t. A. P _' tce All To be m othballed tunnel 9 000 2. eyL) (813)993-2371 year A-5 AEDC Research Cell FSC , I V _ ICE Free Jet D = 0 . 9 du = 0 .3 150 to - 3 0 0 to 0 . 2 to 15 to 3 0 Various m odern J. Hunt A H ......... - _ - ...........
(Arnold AFS , TN) d = 0. 3 _ et =0. 7 15 000 3. + instru m ent s ( 6 15)455-2611 I y ea r A-6 Rosemount ( M inneap o l i s, MN) (a ) Lo w Speed MS ICE W in d H = 0. 1 5 hu ffiO. 1 9 0 to 17 0 -3 0 0 0 .2 to 2 0 to 40 O i l slide (r o t . R . DeLeo All R o se mo unt use only tunnel W = 0.1 wu = 0.07 ! 1.5 cyl. ) (612)941-5560 lea r L=0.3 (b) High Speed I V _ ICE W in d H = 0 . 1 5 hu = w u = 0.1 90 to 740 -25 0 to 0 . 1 to 1Oto 40 Oi l slide (rot. R . DeLeo All Rosemount use only tunnel W = 0.3 3 0O0 3.0 cyl.) (612)94 1 -55 6 0 Tea r L=0.8 A-7 F r os t T unn el I _, IA I CE W ind D = 9. 5 d u = 0. 3 [0 t o 2 40 - 2 0 0 0.4 t o 2 0to 50 Oi ls lide ( r o t . E. Gat es Al l ................. _....
(U ni v. o f Albe rts , h ome! ( O c to gano[ 3 . 0 (n ozzle s cy l .) (403)43 2 - 518 0 T ear Ca na da) L = 0.9 c hang ed) A-8 ucLA Cloud Tunnel MS , CP ICE , R Vertical H = W hu ffi w u = 0.1 0 to 55 -39 0 0.1 to 2 to 50 Var i ous m odern H. Pruppacher All Free par ti cle suspension wind = 0.15 _ 3. i ns tru m en ts (213) 8 25-1038 r ear tunnel L=0.5 A-9 Army N a tiek R&D G , FSC, H FR , R, S Wind H = 3 ........... 4 to 6 5 -3 0 0 10 e m Not measur ed M. Kellberg All M a inly physiol o g i c a l (Natick , Mass.) t u nnel W = 4.5 and r a in / ( rai n g a uge) (617) 6 53-1 000 year tests of hu m a ns C lim atic C ha mb e r L = 18 lower h r .
B. E NG INE TES T FACILITIES • [Not e that m o s t f ree j e ts can do w ind tunn e l types of t e sts. ] Fa- Facil i ty na m e Types o f Wea th e r T y pe o f S i ze (see sketches) , m R ange of p ar ameters used in icing tests c Instrume n ts Techn i cal Test Co mm e n; ci li t y (Loca U on) icing si mu - faci li ty used for person to sea- no. tests r un l at ed Test Un i for m Air speed, Min. to tal Alti- LWC. Vol. re ed local drop contact s on cha m ber ici ng c lou d km / _ r a i r te r n - h i de , g / m 3 d ro p si z e and perat ur e , m size, (LWC) (a ) (b) °C u m B - 1 AEDC (Arnold AFS , " IN) (a) ETF EDC ICE Dir ec t D = 3.7 S pra y bars 0 to -30 0 to 0. 2 to 15 to 30 Vario us modern J. Hunt ALl ......................
connect or 4.5 s iz ed to M = 0.7+ 15 000 3.+ inst rum ent s ( 6 15 )4 55-2611) year d=1.5 L = 11 eng i ne ( b) Free Jet CPU , FSC ICE FreeJet D = 3.7 Spray b ars 0 to - 30and 0 to 0.2 to 15to30 Vario us m od e rn J. H u nt All ......................
I , MS d=l. 5 or 4.5 siz ed to M = 0.7+ lower 15 00 C 3.+ instru m ents (615)455 - 2 611 year L = 11 eng i ne (c) A STF CPU , FSC , ICE Free Jet D = 8 Sp ra y ba rs 0 to -30 and 0 to 0.2 to 15 to 30 Var i o us m odern W. B ates All Pla n n ed for 1983 I d ffi2 .7 L = 18 sized to M = 0.7+ lower 15 000 3.+ i nstr um ents (615) 4 55 - 2611 year eng i ne B-2 Detroit D i esel A lli son (I n d i a n apolis, IN ) (a) Co m p. Test In let a n d ICE FreeJet D = 2.3 Spray bars 0 to M=0.7+ - 30a n d 0 0. 2 to 15 to 40 R o tat i ng W. S ti efel All ......................
F ac ili ty co m pres- Direct L ffi 9 sized to lower 0 to 3.5 cy li nders (317)24 3 -4066 y ear sor s tage co nnec t engine 6 000 d= 0.5 (b) Sne L l Eng i ne EDC ICE D i rect D = 0. 4 5 S p ra y bars 0 to - 30a nd 0 to 0.2 to 15to40 Rota ti ng W. St i e f el All ......................
Facil ity co nnec t [. = 1.2 si z ed to M = 0.7+ lower 6 000 3.5 cy li nder s ( $ 17)243 - 4066 y ea r e n gine B-3 GE Cr o ss-w in d CPU , pal , ICE Free-Jet Outdoors d u = 4.5 90 Ambi e nt 0 0.4t o 15to50 Knol ten berg R. K e ller Win .......................
Fac i lity R d out d oo rs ' a ir to 3.5 spectro m eter (513)243-4483 ter (Pe e bles , OH) d = 7.0 - 20 ( rot . cyl.)
B-4 P&W A l t i tude Faci li ties (E . Hartford, CT) (a) Lar g e EDC , I ICE D i r ec t D=5.5 Sp rayba rs 0toM=0.5 -25 0to 0 .2 to 15 in4 0 O l lslide J. Barlock A l l ......................
connect L = I0 sized to 6 700 9.0 (203)565 - 2091 y ea r e n gine ( b) S m aller EDC , I ICE D i r ec t D = 3 . 7 Spray bars 0 to M =0.5 - 30a n d 0to 0.2 to 15to40 O i l s lide J. Bar l oek A l l ......................
connect sized t o l ower 6700 9.0 (203)565- 2 091 ye ar eng in e (c) P&W S e a Level EDC ICE Di r ec t V a r i es S p ra y bars 0 to - 20 0 0.2 to 15 to 40 Di l s lide J. Ha r to ck Wi n.......................
Faci li ty con nec t with test sized to M = 0.5 (am - 9.0 (203)565 - 2 091 ter celis e ngin e b le n t) B -5 M cK inl ey C l i ma tic L a b CPU, FSC ICE , SI Fa n b l own H = 7.5 hu =3 0 to (30 to ' 1 o ) -3 b a n d 0 0 .1to 12to60 Par ti cle in ter- R. T o live r A l l ......................
Eng in e Test Cel l -- spray W = 9 w u = 6 lower 3. _ fero m eter (904 ) 882 - 3626 r ea r ( Eg lin A FB , F L) F R , R 80 0 to 150C i nd o ors L = 40 ( ru t. cy l . ) n o zz le s c h a nge d ) B. Concluded. E N GINE TEST FACILITIES [Note that most free jets can do wind tunnel types of tests. ] Fa - Fac i lity name 3 _t pes o f Weathe r Type o f S i ze ( s ee sk etches) , m Range o f para m eter s us ed in icing te s t s c Instrume n ts Technical Te s t Comme n t :i ll ty (Locati o n) icing si m u- facility used for person to sea- no. testa ru n la ted Test Unif o rm A i r speed, M in. t o t a l A Li i- L W C. Vo l . re ed localdrop con ta ct son chamber icing cloud k m / hr air tem - rude , g / m 3 drop size and perature m size , (LWC) ( a) (b ) °C u m B- 6 Naval Air Propuls i on Facility (Tre n ton , NJ) ( a ) Five small engine EDC , C PU, ICE, SI, Free Jet H = W = : Spray bars 0 in - 3 0 and 0in 0 . I to 15 to 5 0 Knollenberg Resource All ......................
cells I , FSC , 1V _ FR , R d = 0.6 L = 6 siz ed to M = 0.7+ lower 15 000 2 . ( n ozzles s p e c tro m eter Mgr. year eng ine changed) and O AF (609)896 - 5655 ( r ot. cyl. ) CO ) Two large sea EDC, CPU , ICE, SI, Free jet H = 4.5 Spray bars 0 to - 30and 0 0. l to 15to50 Knollenberg Resource All ......................
level cells I , FSC, . MS FR , R d = 1.2 W = 7 sized t o M = 0.7+ lower 2. ( n ozzles spectrometer Mgr. year L = 1 7 engin e c h a ng ed) and O AP (609)896- 5655 (rot. cyl. ) (c) Three la rg e EDC, CPU I CE , SI Free Jet D = 5 Sp ra y b ars 0 to - 3 0 a n d 0to 0.1to 1 5to50 Kno ll enberg R e source All ......................
altitude cells I, FSC , !V _ FR , R d = 1.2 L = 9 sized to M = 0.7+ lower 15000 2. (nozzles spectrometer Mgr. _ e a r engine changed) a nd OAP (60 9)896 - 5655 (rot. cyl. ) B-7 Teledyne Al titude Cel ls (Toledo , OH) (a) Chamber 1 CFU , EDC ICE , SI Free jet D = 2. 7 Spra y ba r s 0 to - 30 and 0 to Up 15 to 25 Oil sl i de R . Trauth All FR , R or direct L = 5 siz ed to M = 0.7 + lowe r 15 000 t o 3. (4 1 9)47 0 -323 6 r ea r c o nnect , engine (b) Cha mb er2 CPU , EDC ICE, SI , d = 0.2 H=2 . 5 S p ra ybars 0 to - 30and 0to Up 1 5 to 25 R otating R. T ra uth All FR , R W = 2.5 siz ed to M = 0.7+ lower 15 000 to 3. cylinders (419)470-3236 r ear L = 4 engine B - 8 Avco Lyeom in g (Stratford, CT ) ( a ) Component EDC ICE , FR Direct Sp ra y bars 0 to 370 - 30 and 0 0.1 to 1 5 to 40 Oil sl i de J. Sherman All Fac i li ty connect siz ed to lower 3. (r o t. cyl.) (2 0 3)37 8-8 215 yea r d = 0.4 engine Co)Engine Test ED C ICE, FR d = 0.4 W = 3 . 7 Sp ra y bars 0 to 200 - 30and 0 0. l to 1 5to40 Oil slide J. Sherman All Fa c ili ty H = 2.7 s i ze d to lower 3. (rot. cyl.) (203)378- 82 15 year d = 1. 2 Outdoors eng i ne - 20 Wi n - ter B - 9 NRC , Ce11#4 EDC , CPU ICE,SI Free Jet Hf W Sp ra y baro 0to650 -20 an d 0 0.2to 15 to 40 Ollslide W . Grabe Win .......................
(Ottawa , Canada) or direct = 7.5 sized to lower 2 . (rot. cyl.) (61 3 )993- 2 214 ter co nn ect eng in e d= 0.75 CPU , P d = 2.0 0 to 93 Am.
blent B-10 GarretlcingFacli Li ie s : CPU , I ICE , I SI Free Jet H=3 Spraybars M = -30 and 0to 0.1t ¢ 1 0 t oS0 Rot. cyls. J. Pyne All ......................
(Phoenix, AZ) EDC , or direct W = 4 sized to 0.01 - 0.7 lower 1 5 000 6.0 ( Ro t. cyls.) (622) 2 67 - 3853 r ear Cell 1 , Cell 2 , and FSC , P c o nn ect, L = 10 en g in e Cell 3 d = I. 0 t o •1 C. LOW VELOCITY F A CILITIES Fa - Facil i ty name _ r pe of Weather _ ype of Size (see ske t ches) , , m Range of parameters used in icing tests c Ins t rument s Technical Test Comment cl li ty (L o cat i o n ) i cin g simu- faci li ty u s ed for person to sea- no. tests run l ai ed Test Unifor m Air speed , M i n . total Alt i - LWC, V ol. reed. local drop con ta ct son c h amber i cing clo u d k m / hr air tern- t u de, i g / rn 3 drop size and perature rn size , (LWC) (a) (h) ° C _ m C- 1 N HC Helic o p t er FLT(he l - ICE, F R Win dbl o wn D = _ o S pray Ambie ni wi nd , - 20 0 ' 0 . 1 t o 30to 60 O i l s lid e T. R i nger Win - To be mo th b a ll e d S pra y Rig i copters spray m an i fold 20 to 45 (a m - 0.8 (rot. cyl.) ( 6 13)993-2439 ter i n 1985 (Ottawa , Canada) in hover) o u tdoor s hs = 4.5 (gu sty ) blent) ws = 23 C-2 G.E. Cross W ind CPU , P d , ICE, FR Free Jet D= _ d u =4.5 90 -2 0 0 0.4to 15 in 50 Knnlie n berg R. Kell e r W in - Faci li ty Rd outdoo r s (am- 3.6 spectro m e ter (5137243-44 8 3 ter (Peebles , O H) blent) (ro t. cyl.)
C-3 McKin ley C H ma _ c La b (Egltn AFB, FL) (a) Ma in Cha m ber FS, Rd ICE, SI F a n bl o wn H = 21 S p ra y 0 in (30 - 30 and 0 0. I to 12 to 6 0 Part i cle inter- R. To li ver All L argest cold room FH , H spray W = 78 m anifold to 75e) lower 3 8 00to fero m eter (904) 88 2-3626 year 15 0 0 i nd oo r s L = 76 hs = 3 (depe nding ( n ozz l es ( ro t. cyl.)
w s = 9 on LB) cha ng ed) (b) E ngin e T e s t Cell CPU, FSC ICE, SI Fan b low n H = 7.5 Ma n l fold 0 t o (3 0 -3 0 and 0 0.1t o 12 to 6 0 Part i c l e int e r- H. Tol i ver Al l F R , R sp r ay W = 9 h s = 3 to 75) l o wer 3 80 0 t o fero rn eter (9047 88 2-3026 y ea r 1 500 i n doors L = 40 ws = 6 (depe nding ( n o zzl es (rot. cyl.)
on LB) changed) (c) A ll We ath er Room FSC ICE , SI Fan bl o wn H = 4.5 Manif o ld 0 t o (30 - 30 an d 0 0 . Ito 12 to 60 P a r ticle inter- H. T oli ver All F R , R spray W = 0. 5 h s = 3 t o 75) l o we r 3 8 00t o fe rom ete r (904)882-3626 year in doo r s L = 12 w s = 3 (depe n d ing ( no zz l es i (rot. cy l . ) ouL B) chang e d ) C-4 U.S.Arm y C RRE L F SC, M_ I C E,S I , Fan blown H = 1.1 I 0 to 2 0 -30 and 0 1 t o 10to 6 0 Ca sca d e G. As h ton All C old R oom H , IA F R , R spr a y W = 0. 7 lo we r 2 . 5 i m p ac tor (6 0 3)043 - 32 00 y ea r (Ha nov e r , N H) indoors L = 1. 5 C- 5 Mt. Wa shi ngto n F S , CP, N at u ra l i c i ng o f ti ed dow n eq u ipment o n t o p 0 in 180 - 20 an d 1800 G e n era U y s e v e r e Rotating J. Howe Fall O b s ervat or y M S o f m ou ntai n (gus ty ) l o wer n at u ral c on diti on s c y li n ders (6 0 3)466-33 8 8 to (G orha m, NH) s pri n g C-6 U.S. N avy P M TC . FSC , R, FR Fan b lo w n H = 7.6 hs =w s 0 t o 75 -30a n d " 0 30 c m 50 0 to Oi l slide D. Everett All (Pt. M ag u ) FS, G sp ra y W = L = 1 .2 In wer r ai n / 4500 ( r a i n g auge) (805)9 8 2- 80 1 1 ye ar Cli ma t i c Hanger indoors = 1 8 hr S 5 cm 50to 1 0 0 • s n ow / hr C-7 A c tonEnviron m e nta l G R FR , F an blown H = 6 ds = 2 . 5 0 t o 45 -3 0 a nd 0 10 c rn 10 0 0 t o Notm ea sur e d H. Gil f oy Al l Te s tC orp. S_ spr a y W = 4 . 5 low e r r a in / 4 000 ( r a in g au g e) (6 1 7)263-2933 y ea r ( A c ton , M as s. ) indoor s L = 7 . 5 h r C- 8 NR C G , F S F R , Sd Fa n blow n H = 4.3 d s = 1.2 0 to 55 -30 a n d 0 0.3 crr 5 00 to Scree n method T . Ri nger All (Ottaw a , Ca n ada) sp r ay W = 4.5 to 2.5 l o wer rai n/ 100 0 (accu mul atio n ( 61 3)993-2439 year Co ld Cha mb er #1 i n do o r s L = 15.2 hr r a te) NHC G, FS FR Fan bl own H = 5 ds = 1. 8 0 in 55 -3 0 and 0 0.3dc rn ! 500 to Scree n method T. R i n g er All (Ottawa, Ca n a da ) sp r ay W = 5 l o wer r ain/ 1 0 0 0 (accum u latio n (6 1 3)993 - 2439 y e ar Cold Cha mb er #2) in do or s L = 7 hr rate) C-9 Wyle Labs G , FSC FR Fan blown H = 5 0 to 35 - 30 a n d 0 : 12 c m ...................... M. Clark A ll .....................
( N o r c o , CA) : spray W = 4.5 l o wer rain / (7 1 4)737-0871 yea r Co l d Ro o m indo o rs L = 11 'hr C-10 Arct e 'c C _mnda Lid. G , IA FHd , S d F a n b l o w n H = 3.7 t o 3 5 -30 an d 0 ...... A. N a w w ar Al l .....................
( O tta w a, Canad a ) spray W = 5.5 lo wer (613)592 - 2830 y e a r Cold Roo m i n do o rs L = 9 D. TANKERS F OR F LI G HT TE S TS [In addi tio n, m os t airframe c omp anies can te s t aircraft in nat u ral i cin g . ] F a- Facility name _ p e s o f Weather Time i n Size o f s pr ay, m Range Of parameters used in icing tests c Instruments Technic a l Te s t C o m m e n t ci Li ty (Location) icing si m u- icing at used for person to season no. te s ts r an lated high At nominal M anifold A ir speed, M tn. total Altl- LWC , VoL re ed. local drop contact (find LWC , di stance km / hr air tem- rude g / m 3 drop size and temp.
rai n L B IAS per a tur e m size , ( L WC) at (a) (b) °C / _ m al ti tude) D-I Air Force (Edwards AFB , CA ) (a) KC 1 3 5 Tanker Fit. ICE , N 80 At ds = 1.2 300 t o 6 50 -20 1200 0.0 5 1o 2 8 to35 Knollenberg R. M orrison All year Final calibration LB = 60 (370 nora.) (ambient) in 1.5 spectrometer ( 8 05)277-306 8 in 19 3 1 R , F R d=3 8 0 00 0.5 to 20 0 t o 800 ( " ) 32 ; (b) C 130 Tanker Flt. ICE , N 60 At ds = 1.2 190 to 390 -20 1200 0.0 5 to 28to35 Kno li enberg R. Morr l son A li year Planned for 19 8 1 LB = 60 (280 no ra . ) (ambient) to I. 5 desired spectrometer (805)277-306 8 R , FR d= 5 8 000 0.05to 2 00tn 8 00 ( , w ) 32.
D - 2 Ar my HISS He L icopter Fit. ICE , N 30 At ihs = 1.6 110to140 -20 600 0. lto 2 5to30 K nnU enberg C. Franken- NormaLly Test in g to increase Tanker LB = 50 ws = 12 (120 nom. ) (ambient) to 1.0 desir ed spectrometer berger w in ter cloud size (Edwards AFB , CA) h = 3 3500 (Letgh) ( 8 05)277-227 1 w = 12 D-3 C _ s sna 404 Tanker Fit. ICE , R , 60 At ds = 0.6 165 to 330 -20 300 0.05 to 20to49 Ge la tin s Li de D. Hazelwood All y ea r (Wichi ta , KA) FR , N LB = 150 (V-bar) ( 2 60 no ra .) (ambient) to 4.0 (water (J&W) 1 31 6 )94 6 - 6 6 0 6 d = 6 8000 noz z les) D - 4 Piper Cheyenne Tanker Fit. ICE , FR , 14 At hs = 1.2 2 00to 30 0 - 2 0 300 0 . l to 3 0to 50 Gelatin slide J. Bryerton Not (Lock Haven , PA) R ,N LB=3 0 W s= 1 .8 ( 24 0 n ora .) (a m bient) t o 1 .7 (J &W) '.7 1 7)748-6711 summer h = 3 8 000 w=5 D -5 F l ig h t Systems T-33 Fit. ICE , R , 45 At hs = 0.3 23 0 t o 42 0 -2 0 3 00 0.1 to 17to50 Knollenberg J. Ltgo n All year Tanker FR , N LB = 60 ws = 0.9 (370 no ra .) (ambie n t) to 1.0 spectro m ete l (805) 8 24-4 8 01 (MoJave , CA) d = 2.5 8000 ( " ) O \ ,- ST RA TI FO RM CLO U D -10-- \ 2 TEMPERA T URE, ° C , - ,- CU M ULIFO RM "_ I N T ER MI I -r I_IT MAX.
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te H L I _, _ s , \ _- SPR A Y MAN I F OLD , , \ \ _.- ARRAY OFFAN S { a)FAN B LOWN SPRAY I NA LA R GE ROOM OROUTDOORS .
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I , R e por t No . 2. Governme n tAcc _s ion No . 3 . Recip i en t ' s Cat a log N o , NASA T M - 8170 7 4 . Titl e end Subtitle 5 . Regor t Date SUR V E Y OF A IRCRAF T IC ING SI M ULATIO N T ES T February 1981 FA C IL I TIES IN NOR T H AME R I C A S. Performing Or ga nization Code 505 - 4 4 - 12 7. Author(s) • • 8. PerformingOrglni t e tion Report No .
W illiam Ois e n E- 736 10 . Work Unit No , 9. Perfo rm ing Or ga nizationName e ndAddre ss Na tion a l Aeron au ti c s and Space Admin i strat i on L ewis Resea rc h Center 11. Contra ct or Grant No.
Cl eveland , Ohio 4 4 135 13. Type of Report a nd P e riodCovered 1 2. Sl _ ns or ing Agency N a me and Addre s s Technical M e m o r a n d um Nati o n a l A e r o nauti c s a nd Sp ace A d mini st r at i o n 14 . S pons orin g A ge ncy C o de Washing t on, D. C . 2 0 5 4 6 15. Suppleme n ta ry Notes 16 . Abs tr act A su rvey wa s made of th e aircraft ici ng si mu lati onf acilities i n No rt h A me ri ca. This was re - quest e do f NASA by se v e r a l c ommitt ee s c on ce rnedwi t h Air c r aft I c i n g. A s i m il a r s urv e y o f Europ ea n f a c iliti e s h a d a lr ea dyb ee n r e port e din AGARD a dvi s oryr e port1 27 . Th e r e a r e 1 2 wind tunn e ls, 28 e n g in ete st fac ilit ie s , 6 a ir c r af t t a n k e rs a nd 1 4 low v e lo c ity fac iliti e s, t h atca n per f orm v a rious a ir c r af t i c ing te sts f ull or p a rt t i me . Th e surv e y d ete rmin e d t h e lo ca tion a nd sizeo f t h e fac ility, itssp e ed a nd tem p e r a tur e r a ng e , i c ing c loudp a r ame t e rs , a nd t he t ec hni ca l person t o c on tac t. T he s e r e sults a r e pr e s e nt e din ta bul a r f or m . T he ca p a biliti e s o f eac h fa - c ili t y w e r e estimat e dby itst ec hni ca l c ont ac tp e rson. Th e a d e qu ac y o f t he s e fac iliti e s f orv a r- ious typeso f i c ing t estsis dis c uss e d.
17. K ey Words (Sug g e s tedby Au t hor(s)) 1 8 . Distribution Statement Tes t f aci li t i es U n c l as sifi ed - u n l im ited Air c r af ti c ing STAR C a t e gory 0 3 19. S ecu r i t y Cla ss if .{ of t h is report) 20 . SecurityClas s if , ( o f t h i s page) 2 1. No . of Page s 22 . Pr i ce " Uncla ssifi ed U n cla ssifi ed * Forsal e byt h eNa t ional T ec hn i c al In f o r ma t ion Servi c e, Sp r ingfield. Vi r ginia 22 161 N ationa l Aerona u tics and SP EC IAL FOURTH CLASS MAIL P osta ge an d F e e s Pa i d Space Admin i stra t ion BOOK . N a tio na l Ae ro nautics a nd S pace Adm in i s tratio n Washington, D.C. NASA451 20546 O fficial Bu s iness Penalty for Private Use , $300 • - J I _ J / I _A PosThAsTE. , , _° . . ,, *** ab,. , s .
P ostal Man ua l ) Do N ot Return Ib