48
RM L50F23 u—— . . d. RESEARCH MEMORANDUM- STABILITY CHARACTERISTICS AT LOW SPEED OF A 1 -SCALE 4 BELL X-5 AIRPLANE MODEL WITH VARIOUS MODIFICATIONS TO TIZZ BASIC MODEL CONFIGURATIONS By Rokrt E. Becht and AlbertG. Few, Jr. LangleyAeronauticalLaboratory Langley Air Force Base,Va. NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS WASHINGTON August 16,1950 _—

RESEARCH MEMORANDUM- - Digital Library/67531/metadc58515/m2/1/high... · RESEARCH MEMORANDUM- ... The jet-engine ducting was simulated on the model by the use of an ... All coefficients

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RM L50F23

u——.

.

d.

RESEARCH MEMORANDUM-

STABILITY CHARACTERISTICS AT LOW SPEED OF A 1 -SCALE4

BELL X-5 AIRPLANE MODEL WITH VARIOUS MODIFICATIONS

TO TIZZ BASIC MODEL CONFIGURATIONS

By Rokrt E. Becht and AlbertG. Few, Jr.

Langley AeronauticalLaboratoryLangley Air Force Base, Va.

NATIONAL ADVISORY COMMITTEEFOR AERONAUTICS

WASHINGTONAugust 16,1950

_—

NACA RM L~~23

NATIONALADVISORY COMMITTEEI’ORlklIRONAUI’ICS

RESEARCH MEMORANDUM

STABILITYCHMWCT~ISTICS AT LOW SPEEDOF A + -SCALEJ-1

BELL X-5 AIRPLANE MODELWITK VARIOUSMODIFICATIONS

TO THE BASICMODELCONFIGUMTIONS

By Robert

An investigation was

and directional stability

E. Becht and Albert G. Few, Jr.

made of the low-speed longitudinal,

characteristics of a ~ - scale model

lateral,

of a

preliminary Bell X-5 airplane design with various modifications to thebasic model configuration. The extended dive brakes increased the dragcoefficient at low lifts about 0.02 for both 20° and 63° wing-sweepconfigurations and produced a destabilizing shift in the aerodynamic

. center of the complete modeloof the order of 2 and 7 percent of the wingmean aerodynamic chord at 50 sweep for 20° and 60° sweep, respectively.No significant chsmge6 in the longitudinal, lateral, or directional eta-

*bility of the model were obtained by addin~ wing traili rig-edge fillets.Increasing the wing aspect ratio of the 63 configuration from 1.92to 2.25 resulted in a decrease in the longitudinal stability at highlift coefficients. None of the modifications which were made primrilyin an attempt to improve directional stability at high lift coefficientswith 63° sweep were successful in eliminating the rapid variation ofdirectional stability with lift coefficient near the stall.

INTRODUCTION

An investigation of the stability and control characteristics of a1—-4

scale model of a preliminary Bell X-5 airplane design has been con-

ducted in the Langley 300 MPH 7- by 10-foot wind tunnel at a Mach numberof 0.152 and a Reynolds number of 2,000,000. The Bell X-5 airplane isa proposed research airplane incorpor~ting wings whose sweepback anglecan be varied continuously between 20 and 60°. Provision for longi-mtudinal translation of the wing with respect to the fuselage is alsomade.

.

2 - NACA RM L50F23

.The results of the longitudinal etability and control investigation -..

of the basic model configuration are presented in ret%rence 1. Theresults of the lateral and directional stability and control investiga- “

tion of the basic model configuration are jresented in reference 2. This ‘- ~paper contains the results of additional studies of the longitudinal,lateral, and directional stability characteristics of.the model at sweepangles of 200 and 600,,The purpose of the investigation was twofold:(1) to determine the effect of dive brakes- and contemplated design -‘-changes in the wing plan form of the airplane and (2) to determinewhether any improvement in the poor directional stabflity of the 69°configuration at high lift coefficients would be realized by the addi-tion of wing fences, changes in wing incidence, or by use of variousfuselage fin arrangement. (See reference 2.)

SYMBOLS

The system of axes employed, together with an indication of thepositive direction of the forces , moments, and anglee”, is presented infigure 1.

CL

Cx

CDO

Cy

cl

cm

Cn

x

Y

z

L

M

The symbols used in this paper-are def~ned-as f~llows:

lift coefficient (Lifi/qS) _

longitudinal-force coefficient (x/@)

-Cx at CL = o

lateral-force coefficient (Y/qs)

rolling-moment coefficient (L/qSb)

pitching-moment coefficient (M/qS@

yawing-moment coefficient (N/qSb)

longitudinal force along X-axiE. (Drag = -X), pounds

lateral force along Y-axis, pounds

force along Z-axis (Lift = -Z), pounds ~

rolling moment about X-axis, foot-pounds

pitching moment about Y-axis, foot-pounds-

.

b-

.

3NACA RM L501’23

bN yawing moment about Z-axis, foot-pounds

.q ()free-stream dynsmic pressure, pounds per square foot #

s wing

~50 wing

b wing

\</

area, square feet

mean aerodynamicshown in fig. 2)

mean aerodynamic

span, feet

v free-stream velocity,

A aspect ratio (b2/S)

chord, feet (based on wing plan form

chord at 50° sweep, feet

feet per second

P mass density of air, slugs per cubic foot

a angle of attack of thrust line, degrees

$ angle of yaw, degrees

.it angle of incidence

line, degrees

4iv angle of incidence

line, degrees

A angle of sweepbackdegrees

Subscript:

*

of stabilizer with respect to thrust

of wing chord line with respect to thrust

of quarter-chord line of unswept wing,

denotes partial derivative of a coefficient with respect to

( )

hcl -yaw example:

CW = x

APPARATUS AND METHODS

Description of Model

-z The model used in this investigation was a ~- scale model of a

preliminary Bell X-5 airplane design and must, therefore, be consideredonly qualitatively representative of the X-5 airplane..

4 NACA RM L50F23

Physical characteristics of the model are presented in figure 2 anda photograph of the model on the support strut is given in figure 3.Details of the dive brakes, trailing-edge fillets, and extended -ringtips are presented in figure 4. Details of the wing fence and 5°increased wing incidence are presented in figure 5 and several fuselagefin arrangements in figure 6. The 20° drooped horizontal tail alsoshown in figure 6 has the same geometric characteristics as the hori-zontal tail shown in figure 2. The model was construed of wood bonded..to steel reinforcing members.

The wings were pivoted about an axis normal to the wing chord plane.Thus, the original wing incidence measured in a streamwise directionwas zero for all sweep angles. At all sweep angles, the wing waslocated so that the quarter chord of the mean aerodyntiic chord fell o-na fixed fuselage station. The moment reference center was located atthis fuselage station unless otherwise stated. (See ffg. 2.)

The jet-engine ducting was simulated on the model by the use of anopen tube having an inside diaeter equal to that of .fhe jet exit andextending from the nose to the jet exit. .

Teats “

The tests were conducted in the Langley 300 MPH 7- by 10-foot windtunnel at a dynamic pressure of 34.15 pounds per square foot which corre-sponds to a Mach number of 0.152 and a Reynolds number of 2,000,000based on the mean aerodynamic chord of the wing at no sweep for averagetest conditions.

During the teats no control was imposed on the q~ntity of air flowthrough the jet duct. Measurements made in subsequent tests indicatedthat the inlet velocity ratio varied between 0.78 and -0.86,the highervalues being observed at low angles of attack.

Two types of tests were employed for determining the lateral charac-teristics of the model. The parameters CnV, CY+, az CL$ were deter-

mined from tests through the angle-of-attack range at yaw angles of 0°and 5°. The lateral characteristics were also determined from teststhrough a range of yaw a~les at constant aruzle of attack.

&

.

. .

,.

.

b-

NACA RM L>OF23

Corrections

5

\

The angle-of-attack, drag, and pitching-moment results have beencorrected for jet-boundary effects computed on the basis of unswepttings by the methods of reference 3. Independent calculations have

shown that the effects of sweep on the above corrections are negligible.All coefficients have been corrected for blocking by the model and itswake by the method of reference 4.

Corrections for the tare forces and moments produced by the supportstrut have not been applied. It is probable, however, that the signifi-cant tare corrections would be limited to smll increments in pitchingmoment and drag.

Buoyancy effects on the support strut, tunnel air-flow misalinement,and longitudinal. pressure gradient have been accounted for in computationof the test data.

RESULTS ANTIDISCUSSION

Presentation of Results

The longitudinal aerodynamic characteristics of the basic modelconfiguration with 20° and 600 wing sweep are presented in figures 7(a)and 7(b), respectively. These data are taken from reference 1 and arerepeated here to allow for comparison with the longitudinal aerodynamiccharacteristics of the model with the various modifications. Figure 7(a)shao~sthat some discrepancies exist between the two sets of data for the

-tstabilizer setting with the geatest discrepancies occurring mainly

at high lift coefficients. These discrepancies are believed to becaused primarily by small inaccuracies in setting the slat in itsretracted position, thus producing changes in the wing leading-edge con-tour . It is believed that the flagged rather than the unflagged symbolsin figure 7(a) represent more closely the condition of Lhe wing leadingedge during tests of the modifications discussed below. Care should beexercised in evaluating the effect on maximum lift coefficient of themodifications to be presented.

6 NACA RM L50F23

The principal results of the investigation are presented in thefigures summarized below:

FigureDive brakes:

“Longitudinal characteristic . . . . . . . . . . . . . . . . . . . 8Lateral and directional characteristics . ‘. . . . . ; . . 9 and 10

Trailing-edge fillets: +.

Longitudinal characteristics . . . . . . . . . . . . = . . . . . 11Lateral and directional characteristics . ‘. . . . . ; . . 12 and_13

Extended wing tips: .Longitudinal characteristics . . . . . . . . . . . . . . . . . . 14Lateral and directional characteristics . -; . . . . ; . . 15 and 16

Fences:Longitudinal characteristics . . . . . . . . . . . . ; . . . . . 17Wteral and directional characteristics . ; . . . . :- . . . . . 18

Wing incidence:Longitudinal characteristic . . . . . . . . . . . . . . . . . . 19Lateral and directional characteristics . . . . . . . . . . . . 20

Fins:Lateral and directional characteristics . . . . . . . . . . . . 21

4

—.

The aerodynamic coefficients presented herein are based on the wingarea and span of the sweep in question and on the mean a“erodynatic chordof the wing at 50° sweep. Thus, the pitching-moment coefficients are k

based on a reference length which is fixed in the fuselage and is inde-pendent of the sweep angle whereas all other coefficients are of theusual form.

E

Dive Brakes

When the dive brake~ were etiended, an increase in’drag coefficientat low lift coefficient of the order of 0.02 baa realifid for both 20°and 600 sweep configurations. (See figs. 7(a) and 8(a), and 7$;)

()and 8(b).) A destabilizing shift of the aerodynamic center -M

of the order of 0.02?50 at 20° sweep and 0.07550 at 600

when the dive brakes were extended although essentiallylift-curve slope was noted. A nose-do~m trim change atcient6 was also noted for both ,eweepconfigurations.

When the dive brakes were extended, a reduction instability occurred at high lift coefficients in the 20°figuration. Directional-stability reductions were also

~dcL~Tail onsweep occurred

no change inlow lift coeffi-

‘directional.ting-sweep con- —experienced a

.

NACA RM L50T23 7

from CL % 0.1 over the lift-coefficient range In the 60° sweep con-

figuration with dive brakes extended.

Trailing-Edge Fillets

The contemplated X-b wing construction leaves a large cutout at thewing-root trailing-edge juncture with the fuselage when low wing-sweepangles are used. An investigation was made with the cutout covered byan upper-surface fillet of the plan form shown in figure h to determinethe effect on the stability characteristics of the model. Inas?mch asthe entire fillet lies on the wing surface at high wing-sweep angles,tests were made at only 20° sweep and the coefficients computed byusing the basic wing area.

A comparison of the data in figures 7(a) and 11 indicates a slightrearward shift of the wing-fuselage aerodynamic center and a slightincrease in negative pitching-moment coefficient at zero lift probablyas a result of the added fillet area rearward of the wing trailing edge.The longitudinal stability of the model, however, remained essentiallyunchanged inasmuch as the increase in do%mwash at the tail apparentlycompensated for the wing-fuselage aerodynamic-center shift.

The addition of the trailing-edge fillet also produced slightincreases in lift-curve slope and minimum drag. The directional sta-bility remained essentially unchanged but slight reductions wereobtained in the effective dihedral at low lift coefficients (fig. 12).

Etiended Wing Tips

One of the preliminary X-5 airplane designs incorporated a wing ofhigher aspect ratio than that on the model. As a means of evaluatingthis aspect-ratio change in terms of test model characteristics, theaspect ratio of the model wing was increased to that of the airplanedesignby extending the wing tips as shown in figure 4. Since anincrease in aspect ratio would be expected to have a more criticaleffect on longitudinal stability at high wing-sweep angles, the investi-gation was limited to the one wing-sweep angle of 60°. The wing pivotpoints had the same location with respect to the fuselage as in previous60° Wing+weep configurations but the moment reference center was shiftedrearward 1.75 inches as a result of the new mean-aerodynamic-chordlocation. All force and moment coefficients were calculated in a mnnerpreviously outlined with 550 computed as 1.931 feet.

It can be seen in fi’gure 14 that the higher-aspect-ratio wing pro-duced an undesirable decrease in stability at lift coefficientsabove 0.65, resulting in a change in stability throughout the lift

8 NACA RM L50F23

range of considerably greater magnitude than that encountered’ with thebasic plan form. Other longitudinal aerodynamic characteristics of thetest model were essentially unchanged by the addition of the extendedWi?lgtips. —

The directional stability was decreased somewhat although insta-bility was indicated at about the same lift coefficient for both modelconfigurations. (See fig. 15.) Changes in the effective dihedral werelimited to the high-lift-coefficient range where the extended-wing-tipconfiguration had somewhat higher values than the basic model. Thelift-coefficient value at which zero effective dihedral was obtainedwas increased about 0.22 where the higher aspect ratio wing was used.

Fences

Examination of the longitudinal characteristics of the model with60° sweep together with tuft observations of the flow on the wing led tothe conclusion that the flow around the 60° swept wing at high liftcoefficients was dominated by the action of a leading-e~ge separationvortex which contributed to the strong spanwise velocity components inthe boundary layer and flow separation over the regions of the wing nearthe tip. It was anti.ci~ted that an upper-surface fence might divertthe course of this vortex flow and thus alter the spanwise progressionof flow separation. A full-chord fence was installed oiithe model asshowm on figure 5 to determine whether or not the resulting changes indirect forces on the wir?gand in flow direction at the tail would bebeneficial to the directional stability at high lift coefficients. Theeffects of adding the fences are shown in figures 17 and 18.

Figure 17 indicates that the fence produced an undesirable regionof reduced longitudinal stability at lift coefficients near 0.8. Thereduction in the nonlinearities of the lift curve above CL%O.3resulted in less lift at a given angle of attack for the model with thefence than for the basic configuration. A slight’increase in drag,particularly at the higher lift coefficients can also be noted as aresult of the increased angle of attack required to produce a given liftcoefficient.

Figure 18 shows that the fence produced essentiall~no improvementin the undesirable directional stability characteristics near the stall.The rate of increase of CnV with lift coefficient at high lift coeffi-

cients for the original configuration, however, is so great that anymodification to the model would have to produce an extremely largereduction in CnV at high lift coefficients in order to result in any

significant gain in the lift coefficient at which directional insta-bility occurred. The addition of the fence did not change the lift

n.-

.

—.

.

NACA RM L50F23 9

.coefficient at which the model became directionally unstable. The lift

coefficient at which zero effective dihedral occurred wae increased. about 0.22 when the fence was added.

Wing Incidence

Figure 18 of reference 2 indicates that the directional stabilityof the fuselage-tail configuration decreased rapidly with increasingangle of attack. Increased wing incidence was investigated in anattempt to improve the directional stability characteristics by reducingthe fuselage angle of attack corresponding to a given lift coefficient.The results of the investigation are presented in figures 19 and 20.

Figure 19 shows that the increaged wing incidence had no effect onlongitudinal stability at low lift coefficients. Above a lift coeffi-

cient of 0.65,however, the model became ~stable and continued sountil just before stall, probably as a result of the tail being raisedrelative to the wing so that the tail was placed in a region wheredowmwash characteristics differ from those of the basic configuration.The decrease in lift-curve slope above CL % 0.65 and the reduction

in c~ax probably also result from the downwash change at the tail.

Slightly higher drag, especially at higher lift coefficients, was alsoobtained.

.

The directional stability of the original model configurationat 600 sweep decreased rapidly at the higher lift coefficients becoming+unstable at a value of lift coefficient about 0.2 below Cbax” With

the change in wing incidence, directional instability occurred only 0.08below C~ax but the value of C~ax was reduced to such an extent

that there waa no net increase in the lift coefficient at which direc-tional instability occurred. (See fig. 20. ) At lift coefficientsbelow 1.1, the incidence change affected the sidewash at the tail enoughto result in some increase in directional stability, particularly inthe low-lift-coefficient range. The increase in CY+ at low lift

coefficients is almost directly reflected in the increase in directionalstability and increased dihedral effect. These effects at low liftcoefficients are obtained at the expense of the loss in longitudinalstability at higher lift coefficients, the reduction in CLmx~ and the

reduction in effective dihedral at lift coefficients above 0.82.

10 NACA RM L50F53

.Fins — —

Flow surveys in the vicinity of the vertical tail indicated that -the directional instability at high lift caefficlents.was associated __with the presence of a large vortex pattern that cove;ed part of thetail when the model was yawed. Attempts we’remade to~break up thisformation by adding various fuselage, dorsal, and ven~ral fins as shownin figure 6. As a means of adding effective ventral ~ea a droopedhorizontal tail was also investigated, The lift-coefficient value at-zero yaw at which the investigation was made was 1.1 f-u-all fin :Q.arrangements. No significant improvements fi.either directional orlateral stability of the model were produce-dby any o~the fin configu-rations. (See fig. 21. )

The several modifications investigated in an a’ct.&mptto Improvethe directional stability at high lift coefficients at 60° sweep werenot particularly beneficial. It Is probabl=, however; that the direc-tional instability encountered would not have serious adverse effectson the flight characteristics of the X-5 research airplane since landfingsat high sweep angles are not contemplated. ‘For military designs, maneti-vers requiring high lift coefficients at 600 sweep would be undesirablebecause of the high drag coefficients obtained.

.

.

——

CONCLUSIONS —.

An investigation at low speed of the elfect on longitudinal, “lateral, and directional stability of various modifications to the

basic *- scale model of a preliminary Bell X-5 airplane design was made

and the following conclusions are drawn:

1. The extended dive brakes increased t’hedrag coefficient at lowlifts about 0.02 for both 20° and 60° wing-sweep configurations andproduced a destabilizing shift in the aerodynamic center of the orderof 2 and 7 percent of the wing mean aerodynamic chord at 50° sweep for200 and 600 sweep, respectively.

2. The addition of the trailing-edge fillets hadao significanteffect on the longitudinal, lateral, or directional stability.

3. Increasing the wing aspect ratio reeulted in a-decrease inlongitudinal etability at high lift coefficients,

4. None of the modifications investigated primarily in an attemptto improve directional stability at high lift coeffictints tith 600sweep were successful in eliminating the rapid variation of directional

.

v.

.

NACA RM L50F23 11

stability with lift coefficient near the stall. Although changes wereexperienced at low lift coefficients, none of the modifications delayed

. the lift coefficient at which directional instability occurred. Thesemodifications included the addition of a wing fence, increased wingincidence, and the addition of various dorsal , ventral, and fuselageside fins.

5. The lift coefficient at which zero ef~ective dihedral wasobserved was increased about 0.22 when either the higher-aspect-ratiowing or the fence was used.

Langley Aeronautical LaboratoryNational Advisory Committee for Aeronautics

Langley Air Force Base, Va.

RIZFERENCES

1. Kemp, William B., Jr., Becht, Robert E., and Few, Albert G., Jr-:

Stability and Control Characteristics at LOW Speed of a ~- Scale

Bell X-5 Airplane Model. Longitudinal Stability and Con;rol.NACA RML9K08, ~9~.

2. Kemp, William B., Jr., and Becht, Robe~ E.: Stability and Controld Characteristics at Low Speed of a ~- Scale Bell X-5 Airplane Model.

Lateral and Directional Stability and Control. NACA RM L50C17a,1950,

3. Gillis, Clarence L., Pouam~, Ed~rd C., and Gray, Joseph Lo, Jrc:

Charts for Determining Jet-Boundary Corrections for CompleteModels in 7- by 10-Foot Closed Rectangular Wind Tunnels. NACA&RR L5G31, 19~5.

4. Herriot, John G.: Blockage Corrections for Three-Dimensional-FlowClosed-Throat Wind Tunnels, with Consideration of the Effect ofCompressibility. NACARMA7B28, 1947.

l-z? NACA RM L~F23

.

.—, —, ___

x-.

w

Retutive wind

A

Lift

!

ux~

>Relative wind

Figure 1.- System ofvalues of forces,

! z

bfew A-A

\

==@gG= ‘-

,. -–

axes and control-surface deflect”iona. Po8itivemoments, and angles are indicated by arrows. ‘

.

NACA FM L50F23 13

1.--28.44--PSYSICAL CSEWTERISTICS

wing:SWeep, deg..... @Area, Bqft . . . . 10.: 10.?; 10. Z 11.33Aspect ratio . . . . 276 4.56 2.98 I.WSpin, ft...... 7.72 6.90 5.67 4.6Hem aerc&nfmic

chord, ft.... 1.396 1.579 1.s69 2.535Inci&nce, dig . . . . . . . . . . ...0Dihedral, deg . . . . . . . . . . ...-2Mrfoil secticm WI-Fnditiar to O.@:Rat . . . . . . . . . . mm 64(JQ)-O1O.3Tip . . . . . . . . . . . . .MACA @,-C@

Horizontal tail:Area, si ft . . . . . . . . ‘.. . . . l.gkAspct ratio . . . . . . . . . . ...2.’@

VerticaI tail:Area, si ft . . . . . . . . . . ...1.33As~ctratiO . . . . . . . . . . . . . 1.46

5.42

-—- —- — — ----— ----—--—-—---

.-.—_____

1567

Figure 2.- General arrsmgement of test model.

unswept wmg

-7-+ +-—

t---+ –----:

i Leading edge of fillet Sw’ept

53° for 011 wing sweeps,

[I

01020m m m 1 1 1 1 1

Scale, imhes

‘1 I

,,

. I I,,.,, ,. 1,,, ,, ,, \

I~ Figure 2.- Concluded.,!’ ,,

‘ (

11 ,, I

I I

I,,

I

NACA RM L50F23

.

a

Figure 3.- View of test model as mounted in tunnel.

.

LFuselqe Iim d A =20°

Leodlng-ed@ f/!/e 1~ Wing-tip extension

0.40 c?mrd ofunsweptmhg

Tmi{log-e@~ fjller

PHmlcAL cmNmmumlca OF WHO

WITH T12 ~IUl

Swep, dig, ..,...,. ,@

ha, sift, ...,.... 11.96

w=-x~ti....... ,. .2.%Ew, ft . . . . . . . . ,. .5.19bm --. *d, et . 2.h5

Figmre k. - Details of wing-tip extension,

dive brakes,

rD/ ve broke

\

-’”rust’

li3r-.330

c)23

L Dive brake

trailing-edge fillet, and

k Fuselagw line at A =200

~ 0.40 chord of unswept wihg

JJ— 2,?00{

[5-“. ~–i~—~

1.5

t L ‘yh~~

<

Section A-A

Fu.selqe fin? at A 60°

* 35./3+

,, -Thrust” ‘-.:’,

Figure 5.- Details of wing fence and 5° wing incidence.,

“~’1” ‘!1

I

I,, I

NACA RM L5Q~3

.

.

19

Fuse/age fins

~ dorsai n

20°

.

.

High-aspect-ratio ventral

,- 43°Lorge dorsal

2,88

J_~2.3R

t~ 25.30/.75

Fiwe 6.- Details of fins and drooped horizontal tail.

.

.

20 NACA RM L~l?23

Lift coefficient,~

(a) A = 20°. --.

Figure 7.- The effect of tail incidence on the aerodynamic characteristicsof the test model. ‘

NACA RM L~F23 21

(b) Concluded.

Figure 7.- Concluded.

22 T!ACA FM L5CE!3

,h t I

1 , I 1 I 1

4

!

-4 . & f’/ I I -i

I } I I I

-a I 1–“ , , J

-$ 72 0 .2 4 .6 .8 /.0 [2 /,4

— * .—

+

4

Lift coefficient CL

(b) A = 60°. ●

Figure 7.- Continued.

NACA RM LmF23 23

0

-4 [& “I ~

-@4:2 0 .2 4 ,6 .8 /.0 12

~iff c&?ffiGienf,CL

(a) A = 20°.

~’igure 8.– The effect of tail incidence on the aerodynamic characteristicsof the test model. Dive brakes extended.

24 NACA KM L5CM?23

J

-.5

36

32

28

24

;8

4

0

-4

+t+-Hwl

-4:20.24.68 [0 12~iff c~fficiefft, CL

.

.

.

.:.

— —

.

(b) A = 60°.

Figure 8.- Continued.

NACA RM L5CIF23 25

-.8

.7

0

I. .

-3’0.4❑ _50 Horizontal fail off

I I

A

1 I I I I I I I I I I I I I I I I I

-9 + O .2 4 .6 .8 /.0 /2Lift coefficient, c’

(b) Concluded.

Figure 8.- Concluded.

26 — NACA RM L~F23

C“-w

.004

,002

0

-.002

.004

.005

.0a5

“.004

002

(7

.02 ~

‘vo

.

.

-4 :2 0 .2 4 .(5 ,8 10 /2Lift coefficient C’

(a) A = 20°.

Figure 9.- The effect of dive brakea on the lateral-stability parameters

of the test model, 3°it--–.4

NACA R.MLmF23 27

C+f

q‘w

.0/6

.0/4

.012

.0/0

.Oa?

.~6

.004

002

0

-.002

.004

.004

.002

0

.002:2 0 .2 4 .6 .8 10 12 /,4

Lift coefficie~t,c’ =w=’

.02

0“v

(b) A = 60°.

Figue 9.- Concluded.

NACA RM L!XW23

I I I I I I I I I I 1 I I I I

t-i-2zw—

w ‘

[1111 =rTTtlP-l+ I I I I l-l

- -+k#+–I I 1 I 1 1

.

,5

./

-4 0 4 8 /2 /6 20 24 28 32

Angle of yaw, ~&g

Fig.me 10,- The effect of dive brskes on the aerodynamic characteristics -

.

.

.

in yaw of the test model. A = 20°, 3Uit =.--, a-= 0.22°.

RACA R.ML50F23 29

.

.

EDive brakes extended”

-4 0 4 8 /2 /6 20 24 28 32Angle of yow, Y, o’eg

Figure 10.- Concluded,

30 NACA RM L50F23

;6 -4 ~,~ O ,2 ~ .6 ,8 10 /2Lift coefficient, CL

.

.—- :.

- The effect of tail incidence on the aero@amic characteristlcaof the test model. Trailing-edge fillets, A =~~”.

.

.

.

.

NACA FM L5KNY23 31

Cw

.004

.002

0

-.002

.004

-009

O’@

.004

.oa2

o

.002

.02n a

n Traiting-edge fillets u2I !

1

q :2 0 .2 $ ,6 .8 /.0 /2Lift coeffieie~t, c’

o

Figure 12.- The effect of trailing-edge fillets on the lateral-stabilityo

parameters of the test model. A = 20°, it=-;.

2 NACA RM L50F23

u“

Figure 13

in yaw

.0/

o

-.0/

702

.Cu

-.04

.04

.03

.02

.0/

o

-.0/-4 0 4 8 /2 /6 20 24 28 32

Angleof yaw, ~ deg

,

.5

.

—=

.- The effect of angle of attack on the aerodynamic characteristicso

of the test model. Trailing-edge fillets, A = .s00, it =-: ,

.

NACA RM L50F23 33

.

4.2

0

Ei--1f-- \ x 3===~ — — — —

1 -

Lb

Lt-,

Y 1

a, dego .25❑ 9.17

E+-c-i. . .Ki-qmtz-c-., -0 T .. . A m. Y0-

,

r+ .L _+-- . +

f 1

-4 0 4 8 /2 /6 20 24 28 32Angle of yaw, ~&g ~&$~=A/

Figure 13.- Concluded.

34 MACA RM L5D?23

—– . . . . .

-+

.

-4 :2 0 ,2 # .6 .8 Lo /2 /.4Lift coefficient, ~ .

Figure 14.- The effect of extended wing tips on the aerodynamic .-i _ 2Qcharacteristics of the test model.’ A = 600, ~ – - -.

4“

NACA FM L5QF23 35

.9

-.8

-. /

o:2 0 .2 4 .6 .8 /.0 /2 /.4

Lift coefficient, CL

Figure 14.- Concluded.

RACA RM L2F23

Cn?

.0/4

.0/2

.0/0

sow

.CD6

‘ .m4

.002

0

-.002

.004

.0c6

.004

.m2

o

.002

I I II \l

ll\ \l, t / \l

P

t w .

r“-

I

-4 Y2 O .2 4 .6 .8 [0 12 /.4

~if~ ~fficienf, 6“ =Rs=

Figure 15. - The effect of extended wing tips on the lateral-stability~o

parameters of the test model. A.= 60°, it’=-F .

.

.

.02

0 Cyv

NACA RM LWF23 37

m

.02

u’

-.04

I I

-4 0 4 8 /2 /6 20 24 28 32. Angle of yaw, ~ deg

. Figure I_6.- The effect of angle of attack on the aerodynamic characteristicso

in yaw of the test nodel. Extended wing tips, A = 60°, it =-~ .

38 NACA RM L~F23

.

0

Figure 16. - Concluded.

.

.’

.—. —.,

RACA R&fL50F23 39

Figure 17. - The effect of fences on the aerodynamic characteristics of

the test model. A = 60°, it =-;O.

NACA RM L50F23

.

.

-9 72 0 .2 4 .6 ,8 /.0 /!2 /,4Lift coefficient, CL

Figure 17. - Concluded.

.

.

.

NACA RM L9ZF’23 41

.

.

c.v-

CtY

.0/6

.0/4

.0/2

.0/0

.OCU

.(W6

.(W4

.002

0

-.002

-LO04

a%

.004

“ .W2

o

.002

1 I L

-0-.\w

F---ii\

I I I 1 I 1 ! 1 I 1 I I t I I I I [

:2 0 ,2 U .6 .8 /0 /2 /.4

.02

0 Cylf

Lift inefficient, CL -n. . .—-. _.—

Fig.me 18.- The effect of fences on the lateral-stability characteristics

of the test model. A = 600, it =-SO,4

42 NACA RM L~F23

Figure 19.-

cf./

36

32’

28

4

0

-4

.8-’~ :2 0 .2 4 .6 .8 1.0 [2 /,4

Lift c~fficient, c’

The effect-of wing incidence on the aerodyn~c ch=o

of the test model. A=@ O, it=-&

.acteristics

.

——.

.

NACA RM L93F23

.

-.8

o

43

-9 72 0 .2 4 .6 .8 /.0 !2 1.4Lift cmfficient, CL

Figure 19.- Concluded.

44 NACA RM LnT23

c

,

.

Figure 20.- The effect of wing incidence on the lateral- ~tability

parameters of tiletest model. A = 603, it =.-3E“

.

w. -

NACA RM L93F2345

.

.

.

.06

u-.05

I I I

ittt+l 2

I u

./

I I I I I I I I I i I I I I I I I I

-4 0 4 8 12 /6 20 24 28 32

1 I

Angle of yaw, ~ deg

Figure 21.- The effect of various fuselage, dorsal) ~d ventral finsand a drooped horizontal tail on the aerodynamic characteristics

in yaw of the test model. A = 60°, it =-~”, a = 23.66°.

.02

.05

-.06

— -.

– NACA RM LmI?23

.

5

.4

.3

.2

I I I I I I I I I I I I I

I

Ij ./

L/’ .+++/

A

~iiiii,kf+

,

“1ti

1 1 I , , I /J’

1 1 1 ,

1=8=4

L I I I I I I I I I I I I I I I I t I J

-4 0 4 8 /2 /6 20 24 26 32Angle of yaw, ~ deg

Figure 21.- Continued.

.

.

.

.

.

NACA RM L5KI?23

+

.

47

.

m

.02

.OJ

o

-.0/

-.02

.5

.4

.3

2

./

o

-04 ./

m

.02

.0/

o-4 0 4 8 /2 /6 20 24 28 32

Angle of yaw, ~ deg

I

.

.

Figure 21.- Concluded.

NACA-bngiey -4-22.55- 75