Effects of wing lift and weight on landing-gear loads — NACA-TN-2645 (1952)

Document

‘L___— —, TECHNICAL NOTE2645 EFFECTSOFWING LIFTANDWEIGHT ONLANDING-GEAR LOADS ByDeanC. Lindquist ~ LangleyAeronauticalLaboratory LangleyField, Va.

Washington March 1952 ..-. —-. .. . . . . .

lG NATIONAL ADVISORY COMMITTEE FORAERONAUTICS TECHNICAL IJOTE 2645 EFFECTS OFWINGLIFTANDWEIGHT ON LANDINGGEAR LOADS By DeanC. Lindquist SUMMARY In order to investigate theeffects ofwingliftandweight on landingrgesr loads, droptests weremadewitha small landing gearin theLangley impact basin.Winglift was simulated in these tests by themechanical application of a constant liftforce to” thetestspeci- menthroughout eachimpact.Thetests covered a range of dropping weights between 1000and2500pounds, wingliftfactors between O and2.0,andvertical contact velocities between O and12 feetper second.

Theresults of thisinvestigation showthevariations of msximum landing-gear load, landing-gear loadfactor, andmaximmn upper-mass acceleration withchanges in liftforce anddropping weight at various vertical contact velocities.

INTRODUCTION .

Although landing gears aregenerally designed andproof-tested for a specific landing condition, theaerodynamic liftforces andairplane weight at theinstant of ground contact mayvaryoveran appreciable range of values.For example, thespecialized technique of landing aircraft aboard naval carriers canresult in values of wingliftat contact withthecarrier deck which maybe appreciably greater or smaller thantheweight of theairplane. In addition, manyof the modern tactical military aircraft andsometransport aircraft maybe forced to makeemergency l%ndings in an overloaded condition, inwhich casethelanding weight maybe as muchas twice thevalue of the minimum landing weight.Suchlarge variations inwinglift ’and weight might be expected to havean appreciable effect on themagnitude of. the msximum loads developed in a landing gearduring an impact.Verylittle information, however, is available on theeffects of these variables on landing-gear loads.

Thepurpose of thisinvestigation is to determine theeffects of wingliftandweight on maximum landing-gear loads by means of drop tests of a small landing gearin theLangley impact basin.Physical mcAm 2@t5 simulation ofwinglift wasobtained by themechanical application of predetermined liftforces to thetestspecimen throughout eachimpact.

Thetests covered a range of dropping weights between 1000and 2500 powis, applied liftforces between zeroandtwice thevalue of the dropping weight, andvertical contact velocities between O and12 feet per second.

SYMBOLS maximum landing-gear load, pounds

‘g

~avitational constant, 32.17 feetper second per seco~d g liftfactor; ratio of liftforce to total dropping KL weight Mc effective massof liftmechsmism, 1.3 slugs landing-gear loadfactor; ratio of maxhmmlanding-gear load % toweight of upper mass Vv initial vertical contact velocity, feetper second o r total dropping weight, pounds ‘T Wu weight of upper mass, pounds ~imum vertical acceleration of upper mass, feetper second

iu

per second APPfwmJs Equipment Thebasic equipment usedin thepresent investigation is the Langley impact-basin carriage (references 1 and2) whichincorporates a four-bar parallelogram linkage foreffecting thecontrolled descent of thetestspecimen. Thevertical member of thelinkage towhichthe testspecimen is attached is referred to as theboomandis adapted to receive loading weights in theformof lead barsin increments of 50 pounds, as shown in figure 1. Theminimum weight of thedropping massincluding testspecimen andinstrumentation is 1000pounds, which maybe increased by theaddition of theaforementioned lead barsto a maximum weight of 2500 pounds.

— — NACATN 2645 In order to simulate wingliftforces mechanically, thecarriage incorporates a lift mechanism whichis designed to apply anydesired constant liftforce up to 2500pounds to thetestspecimen during an impact.Theliftforce is applied to theboomby means of a cable and sheave arrangement whichconnects theboomto thepiston of a pneumatic cylinder in sucha manner thatthepiston is forced to travel against theairpressure in thecylinder as themassdescends. Although the airpressure in thecylinder increases w$thpiston travel, theincor- poration of a :pecial cam-shaped sheave in thecable system results in theapplication of an essentially constant upward force to thedropping massduring thecourse of theimpact.Theeffect of theinertia of the liftmechanism under accelerated conditions is equivalent to an increase in thetotal dropping massof 1.3 slugs without, however, increasing theweight of thedropping mass. Theamunt of liftforce exerted on thedropping massdepends upontheairpressure supplied to thecylinder before eachtest. Thevertical liftrodwhichcanbe seenattached to thebaseof theboomin figures 1 and2 is oneof twosuchrods which formthelower-end connection of thecable system. Varying theheight of freedropof theboomprior to theengagement of thelift mechanism permits theattainment of sinking speeds up -to approximately 12 feetper second.

TestSpecimen Thelanding-gear tested wasoriginally designed as a mainlanding gearfora small military training airplane which hada gross weight of approximately 5000pounds.Thegearisof cantilever construction and incorporates an oleoshock strut.A 27-inch-diameter typeI tireis fitted to theaxleof a half-fork yokewhichis attached to thelower cylinder of thestrut.

The shock strut usedin these tests hadbeenmodified forother investigations by removing themetering pinandreplacing theoriginal orifice withan orifice of smaller dismeter. The sizeof thesmaller orifice was calculated toproduce approximately thesame maximum landing-gear loadfactor as in theoriginal design at a sinking speed of 10 feetper second. Thedetails of theorifice andtheinternal “arrangement of theshock strut areshown in figure 2.

Thetotal dropping massis comprised of theupper or sprung mass andthelower or unsprung mass. Theupper massincludes theouter cylinder of theshock strut andallthedropping massabove thecylinder.

Thelower massconsists of theinner or lower cylinder, theshock-strut fluid, andtheremaining parts of thelanding gearwhich moverelative to theupper masswhentheshock strut is compressed. Theweight of the lower masswasconstant at 131pounds.

4 NACATN 2645 Instrumentation Thepresent investigation isbased primarily on measurements of upper-mass acceleration andinitial or contact vertical velocity.

Acceleration measurements of theupper .mass wereobtainedby means of an unbended strain-gage typeof accelerometer having a natural frequency of 85 cycles per second. Thevertical velocity of thelanding gearat theinstant of ground contact was determinedly an impulse typeof electromagnetic generator consisting of a permanent. magnet attached to theupper masswhich moved pasta coilftied to thecarriage. The instsmt of tirecontact was determined by means of a microswitch recessed in thelanding platform. A viewof thelanding gearand instrumentation is shown in figure 1.

All instruments produced an electrical output which was recorded by an oscillograph. Thegalvanometers weredamped to 65 percent of critical damping andhadnatural frequencies suchthattheresponse was essentially flatup to frequencies commensurate withthemeasuring instrumentation.

Themeasurements obtained arebelieved tobe accurate towithin thefollowing limits: Liftforce, percent.. . . . . . . . . . . . . . . . . . . . . . .*IO Upper-mass acceleration, g . . . . . . . . . . . . . . . . . . . *0.13 Initial vertical velocity, feetper second . . . . . . . . . . . ~.1 TESTPROCEDURE In thepresent investigation thecarriage wasrestrained hori- zontally andusedin muchthesame manner as a conventional droptest machine. Thedropping masswasreleased froma given height and allowed to fallfreely to obtain thedesired vertical contact velocity before engaging theliftmechanism. Themagnitude of theliftforce waspreset by inflating thepneumatic cylinder of theliftmechanism to therequired pressure before eachtest.

Thetests weremadewithdropping weights of 1000, 1500, 2000, and2500pounds at vertical contact velocities rmgtig up to u feetper second andincluded wingliftfactors of O, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75, snd2.00. Because of equipment limitations, liftforces greater than2500pounds could notbe applied; consequently, thehigher lift factors could notbe investigated forthelager weights. In thefree- falldroptests theliftmechanism was disconnected; hence, there was no increase in theeffective dropping massdueto theinertia of the liftmechanism forthese impacts.

Alltests weremadewiththestrut vertical andwithout wheel prerotation.

NACATN 2645 PHHENTATION OF RESULTS Table I shows the, testconditions investigated andgives experi- mental values of thecontact or initial vertical velocity Vvn andthe resulting maximum acceleration of theupper mass “~u/g. Also-presented arevalues of themaximum landing-gear load F , defined as theforce f on theupper mass, which werecalculated from” he acceleration measure- ments by means of thefollowing equation:

;U

. .

—+1 Fg=W - WA + Mcyu

[)

Ug Values of thelanding-gear loadfactorng,defined as theratio of Fg to theweight of the~er mass Wu, arealsogiven in table I. The weight of theupper massis equal to thetotal dropping weightWT minustheweight of thelower masswhich, as previously mentioned, was 131pounds.

Thedatafromtable I arepresented in figures 3 and4 whichshow thevsria~ions of Fg and ng with V , and j?u/g with V , respec- V.

Vo tively, forconstant values of KL at eachof thefourdropping weights.

In order to permit a direct comparison of theeffects of liftforce and weight on Fg, ng,and ~u/g at constant valuesVv , thecurves of n figures 3 and4 werecross-plotted againstKL as sh&n in figures 5 and6 and against WT as shown in figures 7 to 9.

DISCUSSION OF RESULTS Effects of LiftForce on Loads Thecwves in figure 5 showthatin thelower range of liftforces (KL< 1.0)an increas= in KL (orin liftforce) by a-given amount results in a decrease in ng (orin Fg)by roughly thesameemount throughout themiddle range of Vvo. As a typical example, figure 5(b), which presents”the results obtained in tests withan intermediate weight (WT= 2000lb),shows thatan increase in KL fromO to 1.0results in a reduction in ng of approximately 1.0at a vertical velocity of 7 feetper second.

Variations in KL produce similar changes in n fortheother weights tested overthesamerange of KL and Vvo. he !?

corresponding values of ~u/g varyonlyslightly as shown by the nearly flatcurves in figure 6 andby thenarrow bandof datain fig- ure4. Thiseffect is to be expected since a change in KL produces an opposite change in ng of approximately thesame magnitude.

6 NACATN 2645 “ At thehigher values of V_. forvalues of KL lesstw 1.() the curves of figures 5(a)Ud 5(b)showthatchanges in KL areaccompanied by muchlarger changes in ng. h thisregion theimpacts areof such severity as to cause thetireto bottom or reach itsmaximum pneumatic deflection.

Thesudden increase in thestiffness of thetirewhentire bottoming occurs causes a sudden increase intheshock-strut telescoping velocity and,consequently, a sudden increase in thehydraulic resistance of thestrut which results in greater values of ng. Theloadon the landing gesratwhich tirebottoming occurs is indicated in thefigures by thehorizontal Mne at 9500pounds, whichcorresponds to theloadon thetireatwhich thedynamic-load deflection characteristics radically change. At thehighest velocities andlargest dropping weights where tirebottomhg mayoccur, therefore, an increase ti KL mayprevent thetirefrombottoming anddeveloping excessive values of ng. The effect of KL on ~/g in thetire-bottcming region is shown h figures 6(a)and6(b~bytherapid decrease in ~u/g as KL is increased at thehigher values of Vvo.

At thelower values of Vvo forvalues of KL less thm 1.0 ahostj alltheimpact ener~ is comprised of thepotential energy associated withthesettling of theunbalanced weight to itsstatic position. An increase in theliftfactor in thisregion reducedng by an smount slightly greater thantheincrease in KL as shown, forexample, by the curves in figure 5 forthelimiting caseof equal to zero.

Forthehigher values of liftforce (KL> 1.0), thedecrease in ng is generally notso great as theincrease in KL,particularly in the lower range of Vvo,as shown, forexample, by thecurves in figure 5(d) whichinclude values of KL up to 2.0. Thecorresponding values of as shown by thecurves in fig- ~u/g ti thisregion increased with KL ure6(d). At thehighest velocities forvalues of KL greater than1.O, however, thechange in ng again was approximately equal to thechange in KL andtheeffects of changes in KL on ~u/g again become quite small.

Effects of Weight on Loads It canbe seenfromfigure 7 that Fg increases with ~ formost However, theincrease of thersnge of and KL,as would be expected.

in Fg isnotin thessmeratio as theticrease in WT. For example, to 7 feetpersecond, an increase in WT b figure 7(a)at Vvo equal — ——— —— — NACATN 2~3 from1000to 2000pounds or an increase in WT by a factor of 2 increases Fg fromapproximately 4150to 6250 pounds or an increase in Fg by a factor of only1.5. In general, thepercent increase in Fg corre~ spending to an increase in ~ ismuchlessthanthepercent increase in WI particularly in thelowest range of Vvo sndhighest range of KL,where Fg remains nearly constant.

At thehighest values of Vvo andlowest values of KL,because of theeffects of tirebottoming, an increase in WT by a factor of 2 Fg by nearly thesamefactor.h resulted in an increase in figures 7(a) and7(b)it is of interest to notethatat thehighest values of VVO theslope of eachcurve following thetransition fromthepneumatic-tire- and-oleo shock absorber to thehard-tire-and-oleo shock absorber is approximately thesameas theslope of thecurves below thetire-bottoming boundary . Because of thelackof datain thetransition region, the fairing of thedashed partof thecurves is somewhat arbitrary.

decreases quite rapidly with WT formost Figure 8 shows that ng Thisdecrease would be of therange of Vvo and KL investigated.

expected since itwaspreviously noted thatoverthesamerange of test wasnotso great as thecorre- conditions thepercent increase in ‘f3 region the sponding percent increase in Wr. In thetire-bottoming transition froma pneumatic tireto a hardtireis again noted by the abrupt increase intheslope of thecurves in figures 8(a)and8(b)at 11 feetpersecond.Following thetransition) ng aga~ decre~es with further increases in WT; quite rapidly Thecurves of figure 9 showthat “fu/gdecreases with WT formostof therange of Vvo and KL investigated. As to would be expected, thevariations in Yu/g areseento be similar those shown by thecurves of figure 8 for ng;however, becawe of the is either greater combined effects of dropping weight andliftforce, ng or smaller than Yu/g depending uponthemagnitude of thedifference between theweight andliftforce.

Since, in general, values of “y~/g weremuchgreater forthe lighter dropping weights, theresults indicate that, if an aircraft is designed onlyfora msximum- or gross-weight condition) critic~loati in attachments forconcentrated weights suchas engine mounts mayoccur during landings madein a light-weight condition, eventhough these attachments maybe satisfactory fortheheavy-weight condition.

t .

.. — NACA TN2645 SUMMARY OF RESULTS “An investigation hasbeenmadeto determine theeffects of lift force andweight on theloads developed in a small landing gearduring vertical impacts covering a range of vertical contact velocities.

The datashowthat, in general, formostof therange of test conditions, an increase in theliftfactor reduced. thelanding-gear load by an amount which wasroughly equal to theapplied liftforce.As a result, variations in liftforce hadonlya slight effect on themsxi- vertical contact mumaccelerations of theupper mass. At thehighest velocities andforliftfactors lessthan1.0,however, tirebottoming occurred andchanges in liftforce wereaccompanied by muchlarger differences in landing-gesr load.

An increase inweight resulted in an increase in themaximum landing-gear load which wasnotproportionately so large as the increase in theweight.Thisrelationship was indicatedby therapid decrease in landing-gear loadfactor withincreasing weight.Themaxi- mumupper-mass acceleration aswellas thelanding-gear loadfactor was muchhigher forthelighter weights. Thisresult indicates thataircraft mayexperience critical loads in attachments forconcentrated masses in landings madeunder light-weight conditions.

Langley Aeronautical Laboratory National Advisory Committee forAeronautics Langley Field, Vs.,November 14,1951 REFERENCES 1. Batterson, Sidney A.: TheNACAImpact BasinandWater Landing Tests of a Float ModelatVarious Velocities andWeights.

NACARep.795, 1944. (Formerly NACAACRL4315. ) 2. Milwitzky, Benjamin, andLindquist, DeanC.: Evaluation of theReduced- MassMethod ofRepresenting Wing-Lift Effects inFree-Fall DropTests of Landing fkSHi.

NACATN 2400, 1951.

——.

— — NACATN 2&5 2G TAMEI I+WDIHo-oEAFi IJJAIH I

I

(3)

lcmo I.xQ f — t , v- Y Vvo Fg F13 % % %3

2 (lb) “g (;s)%

(fps) (lb) (%)

——. . ---- 0 0.33 2,561 1.21 0.37 1.37 0.21 I, 656 1, lx 1.33 2.831.16 4,027 3,121 1.% 1.70 ;.83 .67 1.67 ;.83 2,622 1,8n 2.16 .92 4.091.89 4,525 2.&a 2.10 b.09 1.91 4.091.10 1.48 3,395 2,5M 2.89 3,925 5.032.k5 4,644 2.96 2.22 5.03l.kg 2.49 5.03 4,045 2,$93 3.45 S>H9 1.96 6.553.59 6,55iI 6,046 2.77 6.552.24 3.24 6.55 2.72 5,0% 3.-n 3,* 8.3L4.87 8,659 3.66 8.u 3.07 4.07 8.31 6,448 ;% 7,m 5AM rl.ti 7.02 16,761 % 7.0811.06 6.19 11.06 6,96+ 8.02 13, 43E 7.19 Hi 9,5%

1 1

----— ---- 0 ----- ----

0 .10 2>467 1.10 o 1.32 I-1 -17 1, m 1.17 .32 93 2.15 .48 2.L5 .84 2,766 1.48 2.15 .48 1,% 1.84 1.48 .56 2,136 1.56 2.15 3,506 3.661.64 4,193 l.-i-j’ 3.66 .93 2,31z 2.65 3.65 .~ 1.14 2,923 2.14 3.65 3,@r 1.93 b.6$J 1.15 4.692.= 4,327 2.15 4.691.32 2,&i 2.3-2 1.64 3,614 2.64 5,093 3=5 6.293.32 2.72 6.292.05 4.30 6.291.72 2.46 3.46 x 5, ‘m 3,-M 3.05 b,871 5.61 8.u 2.&I W 8.u 4.61 :;% 7, m 3.60 8.u 2.96 3.96 4.54 8.n 3-54 10.89 6.79 15,481 L!@% 6.5410.M 5.5-J 6,7T 10.M 5.54 6.90 3.36 8,w4 6.56 LO.~ 7-79

1 1

-u

b.702.09 4,169 1.76 5.051.41 2,276 2.62 1.91 2.15 3,%3 5.592.% 4,8% 4,214 2.05 5.83l.~ 2,647 3.04 2.26 2.53 6.I22.94 5, hs 2.29 6.s42.06 3*UX 2.57 2.95 3=9 6,6u4 %% 4.35 3.21 7.373.74 2.79 7.732.69 3,n~ 3.59 4>46$ 8.414.53 3.28 8.863.22 5.14 3.75 7>773 7,009 S.I.O 8,016 5,019 4.29 ;:: 9.3 9,365 3.$5 9.813.74 5.78 3.E!J3 1.75 2,528 1.35 1,714 2,953 1.% 4.642.21 %! 1.94 2, 1.3t 3,6X 3,aJ6 1.72 2,510 5.352.63 4,279 2.89 1.98 2.3 3,@k 6.7f3 3.36 4,936 3.63 2.64 3.01 3,175 5,52L 4.84 4,a14 8.444.49 7,06J+ 6,370 3.41 3.* LO.94 6.42 6.87 5.24 11,970 9,890 5.53 5,W 2.501.31 1,846 1,465 1, O@ 1.22 .% .@ 3.631.76 2,654 2, lgl 1.35 1,4P 1.17 1.69 4.522.25 2.21 3,256 2,726 l.m L.b6 6.122.98 4,43a 2.43 ;%? ?.IJ 2.97 3,949 7.854.11 3,@3 6,293 5,478 3.39 ?.93 % W.46 6.25 9,441 8,325 5.04 5,559 k.45 2.261.29 1,366 .83 1.$25 3.?i5 1.05 .73 .91 3.691.7g 1.2L 4.401.38 1.07 1,% 1.43 1,937 1,641 4.402.22 2,608 1.55 5.291.70 L.bo 1.WJ 6.003.03 3,63 2.20 6.782.23 1.94 2,379 2.74 7.734.04 5,064 3.17 8.322.99 ?.73. 3,29~ LO.17 5.92 4.50 10.64 4.14 5,016 ;:!?

7,2n 3.89 .

-L

.67 2.x 1.33 .70 m 1.50 :.3J:.$ 1.09 1,031 1.26 1.36 1,469 1.69 6~093:13 2.05 2,21.7 2.55 7.673.99 3,007 3.46 2.98

r

9.995.6a 4.00 4,540 5.22 1.731.2.3 214 =5 1.75 3.452.00 1.08 4.462.41 1, 3L6 1.5L 5.262.87 l.$g 7.123.80 2% 2.93 4.42 / 9.165.I.8 3,839 :g 2.251.59 3.5 2.00 3.402.05 4.592.64 l,m 1.46 .

6.543.73 2,2a 2.61 8.@34.92 3.86 3,353 .

p * b -.. . —.. ..— ._,_ _____ ___ _ -— —-— ——.—— 10 NACATN 2645 .

Fifyme l.- ViewGf landing gearandinstrumentation.

—— l-l NACATN 26k5 IANDIHG-GEAR SPECIFICATIONS

l-’

Air-supporting area,sq h. . . . . . 8.30

Attachment

Oil-supporting area,sq in. . . . . . 6.78

n,,-- ‘~ti

1 1 1 1 Air volume - extended, cu h . . . . 61.26 I 7; stroke, ~,ti . ... .....

‘1 I

I static ~sion, in.........

z Fluidspecification . . . . . . AN-WJ3-33& Fluidvolume, cu in. . . . . . . . . =3 strut inclination b vertical, deg . .

Tirecliameterj h...... . . . . 27 Tire type.....tioth-contour (type I), nonskid treh~ Tire pressure, lb/sq in. ......

Landing-gear weight, lb ... .. .. 123 Unsprung weight, lb .........

Strutairpressure, P, lb/sqin. . .

IiT Pti=ded P~titic 2yo 43.5 2S5. 3 p)flz;~zm? J (--l-y , Znco 34.3 225.3 Iyo ~.; 165.0 1ooo. M4.8

Orffce &fat/s

I

tDlmens/w InIdes) .%---- ------

t +

I Figure 2.-Landing geartested in Langley @act basin.

.— .—-.—- ——.

. ...—— — -—————— --—— — — — NACATN 2645 (a) WT = 2500pounds .

Figure 3.- Variation of landing-gear loadandlanding-gear loadfactor withvertical velocity.

NACATN 2&5 13 d /4 x/’o~ I K~ /2 0 .50 .

6 .75

1 .- /m

/a I v /01 I I (b) WT = ~00 pounds.

Figure 3.- Continued.

————— ——— —— — .—. —— - .——. —— .-—- - NACATN 2645 /2 x lo?

, .

f’f~ /0 o * A j.~ -8 - b /.30 k!?’ , b- .2 / $ w’ / c % ~4 z / o 0 z 4 6 /0 /2 Inhi verr?cdvelocdy, Vvo,fps (c) WT= lmo pounds.

Figure 3.- Continued.

—- .- ..— — — — NACATN 26k5 (d) UT = 1000pounds.

Figure 3.- Concluded.

._——. _ _____ .—— —.—.—.. . . . ..

..— . ..— —-— ——.–—- -——— -——— NACATN 2645

K~

Q

0 -----.50

I :

I?J

o —— .75

t A —f-m :

5 /

l .,.

I .

z

/

...................-

----

/0 /2

z 4 6 d

livtd ver+~col vabcdy,VVO, fp

(a) WT = 2500pounds.

,, withvertical velocity.

Figure 4.-variation of upper-mass acceleration ,, . ..— ——.

NACA m 2645 17 3G .

/ ( .

( > ; /(- . .

...........

o 0 ; : ----— •1 Jo : .

—— .75

A — I.m .- v —“—I.G .- .

/ / >.&;:..> .-“ w >- dl 4 6 /0 0 z 8 /2

In/t/u/ vert]cd vekwtg, VVO, fps

(b) WT = ~00 pounds.

Figure 1.-Conttiued.

— .— —— —-— —— NACATN 2645 d { 6 ,J “. .

.“ ,.~” . .- . . .

I . . .

K[ , //.

...........

.’... ‘; •1 —-- .50

.:s%

I /+. .

o —— .75 .-— .

-1 ..- A — I.w 8-..-1 /

..-#?’Trr

I I I 1 I 1 I I t ;&-%7~ L I I I I 1 I t I 1 1 1 L v (c) WT = lm pounds.

Figure k. - Continued.

TN2645 lg (!3

7 n

..-

fi~

--- ...........

~ .-

‘—- .50 ::A A —/m b –.-–/.39 Q —---(200 L

4-

3 — —

z

...-

0 2

4 6

8 /0 12

Inltlu/ ver+jcul velocltg, Go, fp (d) WT = 1000pounds.

Figure k..Concluded.

. . .. . -_..—— —-———. .— —__ ..

,’ /6 X/03 \ A ~ /- I I 1- !

n [00 /!6 /!0 0 4?5 .50 -70 L/ff fociw, Q (a) WT = 2~ pounds.

loadandlanding-gear Figure 5.-Effects of winglifton landing-gear loadfactor.

,, —.

NACA!IN 2645 a.

,, o .25 .50 .75 km m m bff fuc+or, AL (b) WT = ~0 pounds.

Figure 5.- Continued.

—— —...— - -. .—— NACATN 2645 18X I@.

/ — 8 \ 6~.

.ixi .50 ml . ,’50 0 .75 L?5 tit fuc+or, KL (c) WT = lWO pounds.

Figure 5.-Conttiued.

— .

NACATN 2645 .

8, I I

171-%1

FE 61,

: w , “

+++ , 1 I I I I I I I I I I ! I I o .25 .32 .75 /!00 ZZ5 M’) 175 Loo Lft foctw, K~ (d) WT = 1000pounds.

, Figure 5.-Concluded.

c .—. —_ _____ ..__ — ——— .

—-— —.

NACATM 2645 v- \ TIm-bol%rnl J&l LwldoP~ I 4 -\ # ~ _ I 2~- - — — -1--- ~

I

, t /

0 Am

.Z5 -50 .75 M5 150 Llfi fdw, KL (a) WT = 2500 pounds.

Figure 6.- Effects of winglifton upper-mass acce lerat ion.

—— 4G

T-

—

Q -+ --t 4- -- - — /; I o .25 .50 .7s /.0 125 km .L)fi facfor, K~ (b) WT = 2000pOlllldS.

Figwe 6.- Continued.

——— — —— —...._. _ ——–. _ NACATN 2645 b1 Z..- Aiv70mmg bound arq u 5 -’ ~ _ /0 Ill, I 4 ~ - 3 T , I — 2 - — — 5. _ — & . — ~

,Lrr

I I

ifl

i I ml o ./a .50 .75 lCU L% L50 L]ft fucfw, KL - (c) WT = 190 pounds.

Figure 6.- Continued.

l “ — NACATN 2645 = MOO pounds.

(d) WT Figure 6.- Concluded.

—..—. . — -.

- ———- NACATN 2645 16X~03 / / /4 / / / / / /2 Vvo= Ilfps/ Y * , r, /0 / ~ — — — — — — A ,’570 Zcw Tofu/ d~ppmg we@’. WT, 6 (a) KL = 0.

Figure 7.- Effects of weight on landing-gear .

— MCA m 26k5 /z’x/o~

/ ‘

/ Zre-boff Cm/.. bouCWiui’y /0 — — u- / — — — — u a - .

z — I I I I ~1 I I I ~ ~1 J_’ I o

iw /500 ZCw 2500

TOW dmppng W@#, YYT,Lb WS= Figure 7.- Continued.

, .—— —— —— —.—— .— —.. ——. — —. .. . ..-— - —— —— NACATN 2645 /2 -1 .

+++ .

/500 2000 2500 Tofal o!roppmg weigh< WT, lb ~ (c) KL = 0.75.

Figure 7.- Continued.

“ —-.— NACATN 2@k5 .

~oful dropping weigh< V@, lb (d) ~ = 1.00.

Figure 7--- Continued.

— —- —. —_. ..— /m /500 ’00 =E= Iwo drqopmg weqh f, WJ, lb Total (h) ~ = 2.00.

(e)q = 1.25. (f) ~ = l.!m.

(g) ~ = 1.75.

Figure 7.- Concluded.

, , .

NACA m 2&k5 5G . .

\ z I 1’1 / I I I i I I I I I I I

I I I I I I , I I I =!s3=

o

z5a9

a /tvo “ Zoco

70+0/ dropping wegh+, WT,b

(a) KL =0.

Figure 8.- Effects of weight on landing-gear loadfactor.

——. — .— ———— -—c ——— .—— .— -=—— ——— . . . . . — mm m 2645 .

J .

(b) ~ =0.93.

Figure 8.-Continued.

—-. — —— NACA m 2dt5 .

/ .

T/r@ - X50tt Ommg bow? Off/’g \ z \ , / ~ — — ~ ~ — _ — o

Am

/m Z(X2J 70+0/ droppjng wegh+, W~, (c) ~ = 0.75.

Figure 8.- Conttiued.

—.-— -- —-— -- ——z ) NACA m 2@t5 .

/( /5m Zmo ToM droppingweigh+,W~, /b (d) KL = 1.00.

Figure 8.-Continued.

-- 140 =// 7)s l l /0 -— .

9- , —. –8– l 7 I l 6 !5 ‘4 l 3 l z /000 /500 dro~ping we~gh ~ +, /b (e) ~ = 1,25.

(f) ~ = l.m.

= 1.75. (h) ~ = 2.00.

(g) ~ Figure 8.-Concluded.

NACATN 2645 .

7ire ~ bo7%m?/ng b!!ufldorjJ -

- \

I

/

‘fp/

. v%=

/ .

s%

-t /0 -9 — -3 I I I 7- ----T----- - oi i i /000 Zooo 2500

fifal droppfng Weight, WT, /b

v

(a) KL =0.

Fig&e 9.- Effects of weight on upper-mass acceleration.

. ..— ./ c I I I I I .

/ i— 11+!

(b) KL = 0.9.

Figure 9.- Continued.

/ .——e . . . .— —— —— — —- — NACA m 2645 .

!“ .

/ I

2000 2500

/000 /500 (c) KL = 0.75.