Document
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TECHNICAL MEMORANDUM
x - 47
STATIC STABILLTTY AND CONTROL CHARACTERISTICS O F AN AIRPLANE MODEL WTI" TAIL SURFACES OUTBOARD O F THE WING TIPS AT A MACH NUNIBER O F 2.01 - --. - By Cornelius Driver and M. Leroy Spearman I
- *
CLASSIFIED DOCUMENT - TITLE UNCLASSIFIED x . " o This material contahs information affecting the natloial defense of the United States within the meaning o e c r u of the espionage laws, Tltle 18. U.S.C.. Sees. 783 and 794, the transmission or revelatLon of whlch in any w - inanner t o an unauthorized person i s prohiblted by law.
# 3 % E
NATIONAL AERONAUTICS AND SPA^ 'ADMINISTRATION
September 1959
WASHINGTON
CON FI DENTIAL
. . . . . . . .........................
0 .
........ 4 . . . . . . . . . . . . . . . . .. 0 . 0 .
.
...... ................................. . .... 0 . . 0 . e .
. . c 0 .
CONFIDEPJTIAL NATIONAL AERONAUTICS AND SPACE MMINISTRATION TECHNICAL MEMORANDUM X-47 STATIC STABILITY AND CONTROL CHARACTERISTICS OF AN AlRPIAIW MODEL W I T H TAIL SURFACES OUTBQARD QF TRE WING TIPS AT A MACH NUMBER OF 2.01" By Cornelius Driver and M. Ieroy Spearman SUMMARY , $ An investigation has been conducted in the Iangley 4- by 4-foot supersonic pressure tunnel at a Mach number of 2.01 to determin4the static stability and control characteristics of an airplane cmkigura- tion with tail surfaces outboard of the wing tips.
Complete model tests were made with two sizes of horizontal tails. In addition, tests"were made of various combinations of component parts.
The results indicated that values of maximum trimmed lift-drag ratio were relatively insensitive to stability level up to a static margin of 26.5 percent. The highest value of trimmed lift-drag ratio obtained was about 6.35. All configurations indicated a positive dihedral effect, and the complete configuration indicated positive static directional stability at the approximate angle of attack for the maximum trimmed lift-drag ratio.
INTRODUCTION Recent investigations have indicated that airplane configurations employing horizontal tail surfaces outboard and rearward of the wing tips should provide an improvement in performance characteristics over more conventional designs. Low-speed studies of some.models with tail surfaces outboard of the wing tips and a discussion of some of the basic concepts and applications of these designs are presented in reference 1 . Wind- tunnel studies at supersonic speeds of some models with tail surfaces out- board of the wing tips are presented in references 2 and 3 . Further refinements have subsequently been made to the configuration reported in reference 3, and tests of the revised model are presented herein at a Mach number of 2 . 0 1 . The model was tested prirmarily in pitch with various ?itle, Unclassified.
CONFIDENTIAL
......................... 0 0 b - 0 0
0 . 0 . 0 .
0 * . . ........
0 . . . . . . . . . . . . . . . . . 0 . 0 . . .... b ......
.......... . 0 . . 0 . .
0 . v . .
control deflections for two sizes of horizontal tails although some limitel sideslip data were aJso obtained. In addition, some results for various combinations of model component parts were obtained.
COEFFICIENTS AND SYMBOLS The results are referred to the body axis system except for the lift and drag coefficients, which are referred to the wind axis system.
The moment reference point is at a longitudinal station corresponding to the quarter chord of the mean geometric chord.
The coefficients and symbols are defined as follows: Lift lift coefficient, - qs b a g coefficient, Drag qs Pitching moment pitching-moment coefficient, qsc Rolling moment rolling-moment coefficient, qSb Yawing moment yawing-moment coefficient, Side force side-force coefficient, qs free-stream dynamic pressure area of wing including fuselage intercept plus horizontal tail, sq in.
mean geometric chord of wing plus horizontal tail, in.
span of wing plus horizontal tail, in.
angle of attack, deg angle of sideslip, deg horizontal tail control deflection (measured with respect to outer body center line), deg CONFIDENTIAL .........................
0 . 0 . 0 . b 0 . 0 0 . 0 ........
..........
.............................. . e . 0 .
L.3
€ effective angle of downwash, deg L/D lift-drag ratio, CL/CD d irectional-stability parameter CnP C effective-dihedral parameter l P longitudinal-stability parameter lift-curve slope
cLa
a€
-
variation of effective downwash angle with angle of attack
aa
Subscripts: max maximum 0 value at zero lift trim value measured at C , = 0 Model component designations: B body H horizontal tail W wing
v vertical tail
0 outer body E engine pack MODELS AND APPARATUS Details of the model are shown in figure 1 and the geometric characteristics are presented in table I. The model consisted of a CONFIDENTIAL body having a semielliptical cross section with the wing mounted essen- tially flush with the lower side of the body.
Beneath the wing-body was a simulated six-engine pack with a vertical two-dimensional split inlet ducted to four exits. Outer bodies were attached to the wing tips for the purpose of supporting the vertical and horizontal tails. The rear portions of the outer bodies were deflected 1 . 3 ' inward and 3 O upward.
Thus with respect to the body reference axis, the vertical tails were mounted with the leading edge deflected 1.3O outward, and with respect to the wing-chord plane, the horizontal tails for it = 0) were mounted
(
with the trailing edge deflected 3 ' upward. Two sizes of horizontal tails were tested (designated small and large). The tails were all- movable with the hinge line at 90 percent of the root chord.
The model was mounted in the tunnel on a remote-controlled rotary sting, and force and moment measurements were made with the use of a six- component internal strain-gage balance.
TEST CONDITIONS AND CORRECTIONS T i n e tests for this investigation were conducted in the Langley 4- by 4-foot supersonic pressure tunnel at a Mach number of 2.01, a stagna- tion pressure of 1 0 lb/sq in., and a stagnation temperature of llOo F.
The stagnation dewpoint was maintained sufficiently low ( - 2 5 O F or less) to prevent condensation effects in the test section. The Reynolds n u -
ber, based on c' with the small horizontal tail, was 3 . 3 x 10 . Limited
6.6 x 1 0 6 . However, since a
data were obtained for a Reynolds number of comparison of these data with those obtained at a Reynolds number
of 3 . 3 x lo6 indicated little significant difference (fig. 2 ) , the
remainder of the data were obtained at the lower Reynolds number.
Tests were made through an angle-of-attack range of about - 4 ' to and through a sideslip range from -2O to 6 O at angles loo at p = Oo of attack of 0 ' and 4 ' .
"he angles of attack were determined directly by optical means and required no correction, whereas the angles of sideslip were determined indirectly and have been corrected for the deflection of the balance and sting under load. The base pressure was measured, and the drag force was adjusted to correspond to a base pressure equal to free-stream static pressure. The drag has been corrected to account for the internal flow through the engine pack.
CONFIDENTIAL DISCUSSION Longitudinal Characteristics Effect of component parts.- The aerodynamic characteristics in pitch for various combinations of component parts for the model with the small horizontal tail are presented in figure 3 . The addition of the outer bodies provides a small increase in lift-curve slope as a result of the end-plate effect on the wing and a small increase in longitudinal stabil- ity. In addition, the outer bodies cause a slight increase in minimum drag and a decrease in the maximum value of L/D.
The addition of the horizontal tail results in an increase in lift- curve slope because of the effective increase in aspect ratio. The horizontal tail, of course, provides positive longitudinal stability, and because of the 3 ' upward deflection of the outer bodies, a positive increment of the &,o results. A tendency toward reduced stability is indicated for the complete configuration at lift coefficients above about 0.3. The addition of the horizontal tail causes an increase in minimum drag, but because of a decrease in the drag due to lift, the maximum value of L/D is increased. The reduction in drag due to lift is partly a result of the increase in aspect ratio of the wing-tail combination and partly a result of the fact that the horizontal tail is An analysis of the results located in a region of upwash from the wing.
for the complete configuration indicates a drag-due-to-lift factor of 0.436 as compared with a value of 0.478 which is indicated ACD/CL~ The fact that by the reciprocal of the lift-curve slope (1/57.3Cb).
the drag-due-to-lift factor is lower than would be expected on the basis of the lift-curve slope is an indication of the favorable effect of upwash at the horizontal tail. A similar effect would be expected for the configuration with the large horizontal tail.
The addition of the vertical tails has little effect other than to cause a slight increase in minimum drag and a slight reduction in the maximum value of L/D.
Effect of horizontal tail deflection.- The effects of horizontal tail deflection on the aerodynamic characteristics in pitch are shown in figure 4 for the small horizontal tail and in figure 5 for the large horizontal tail. Deflection of either tail provides a uniform variation of pitching moment throughout the lift range. However, because of the reduced stability at higher lifts, the maximum lift obtainable before encountering control reversal is about 0.3.
CONFIDENTIAL a 0 . ......................... o m 0 . 0 . . . . . . . . .
........
.
0 . 0 0 8 . 0 0. m . ..*.. 0
0 . 0 . 0 . . ..e. . . . . .
.......... . s . . 0 . . = . E O f @ ~ & p . . 0 .
Although deflection of the horizontal tail causes an increase in minimum drag, the drag-due-to-lift factor is improved so that the maxi- is not drastically reduced with increased tail mum value of L/D deflection.
The pitching-moment results for the various tail deflections as well as those for the tail off have been used to determine the experi- mental values of effective downwash (fig. 6). At the intersections of the tail-off curve with the tail-on curves (where the tail provides no pitching moment), it is assumed that the tail is alined with the local stream direction and hence the downwash angle can be determined from
E : = a + it. The resulting values (fig. 6) indicate a
the relation negative variation of E with a, or an effective upwash flow at the
tail. The value of a€/& is about -1.1 for either the small or the
large tail. Although the results (fig. 6) indicate a positive value of E at a = Oo, it should be pointed out that the flow angle is referred to the chord plane of the horizontal tail which is inclined - 3 O to the free-stream direction.
Longitudinal trim characteristics.- The maximum trimmed values of L/D as a function of stability level aCm/hCL (measured near zero lift) are shown in figure 7 for both tail sizes. These values were obtained from the data presented in figures 4 and 5 for various arbitrary stability levels. At stability levels for which the values of maximum L/D occurred for control deflections other than those tested, the values were interpolated by assuming a linear variation of pitching moment with control deflection.
The maximum trimed values of L/D are relatively insensitive to stability level over a reasonably large range (static margin up to 26.5 percent). The highest values of trimmed L/D obtained were about 6.55 for both tails, and these values occurred at stability levels of h C , / a C L E. -0.14 for the small tail and of for the aC / a C , P -0.163 m, large tail.
Lateral Stability The aerodynamic characteristics in sideslip for various combinations of component parts for the configuration with the small horizontal tail are presented in figure 8 for angles of attack of 0 ' and 4 ' . The addi- tion of the outer bodies to the wing-body-engine configuration provides The possibility of a stabilizing increment in directional stability.
obtaining this stabilizing increment in directional stability by use of outer bodies was discussed in reference 4 and is an effect that might be expected to increase with increasing angle of attack.
CONFIDENTIAL The addition of the vertical tail provides a substantial increment of directional stability that is reduced slightly by the addition of the
horizontal tail at a = 4 O (fig. 8(b) ) . However, the complete model
indicates positive static directional stability at the approximate angle of attack for maximum L/D ( a = 4 ' ) .
A l l configurations displayed a positive dihedral effect (-czB >.
provided by the vertical tail at a = 4 O is The increment in c z P somewhat reduced by the presence of the horizontal tail. This effect is apparently related to the interference flow field of the vertical tail on the horizontal tail as was pointed out in reference 2.
"he effect of horizontal tail size on the sideslip derivatives (fig. 9) is limited to only a slight increase in -Czp as the tail size is increased.
The effects of horizontal tail deflection on the sideslip character- isti.cs (figs. 1 0 and 11) were quite small and consisted primarily of a with positive deflection and a slight decrease slight increase in CnP in Cnp with negative deflection at a = 4 ' . These effects are char- acteristic of low tail configurations. (See ref. 4.) The effects of horizontal tail deflection might be expected to increase with increasing deflection; however, the - 6 O deflection is well beyond that required for trimming at the maximum L/D.
CONCLUDING RFMARKS An investigation has been conducted in the Langley 4- by 4-foot supersonic pressure tunnel at a Mach number of 2.01to determine the stability and control characteristics of an airplane configuration with tail surfaces outboard of the wing tips. The results of the investiga- tion indicated that maximum trimmed values of lift-drag ratio were relatively insensitive to stability level up to a static margin of 26.5 percent. was The highest value of trim lift-drag ratio obtained 6.55. A l l configurations indicated a positive dihedral effect, about and the complete model indicated positive static directional stability at the approximate angle of attack for the maximum trimmed lift-drag ratio.
Langley Research Center, National Aeronautics and Space Administration, Langley Field, Va. , April 29, 1959.
CONFIDENTIAL REPERENCES Preliminary Study of Airplane Configura- 1. Sleeman, William C., Jr.: NACA tions Having Tail Surfaces Outboard of the Wing Tips.
RM ~58~06, 1958.
Aerodynamic Characteris- 2. Spearman, M. Leroy, and Robinson, Ross B. : tics of a Canard and an Outboard-Tail Airplane Model at a Mach NACA RM L58B07, 1938.
Number of 2.01.
3. Church, James D., Hayes, William C., Jr., and Sleeman, William C., Jr.: Investigation of Aerodynamic Characteristics of an Airplane Configu- ration Having Tail Surfaces Outboard of the Wing Tips at Mach Num- NACA RM L58C25, 1938.
bers of 2.30, 2.97, and 3.51.
Some Factors Affecting the Static Longitudinal 4. Spearman, M. Leroy: and Directional Stability Characteristics of Supersonic Aircraft Configurations. NACA RM L57E24a, 1957.
C O N F I DE NYIA L ..........................
. 0 . . 0 . .
.
........ . . . . . . . . . . . . . . . . . . 0 . 0 . 0 . 0 .
......
. . . 0 . 0 .
.... f
T A B U I.- GEOME’JIRIC CHARACTERISTICS O F MODEL Wing alone:
Area, s q i n . . . . . . . . . . . . . . . . . . . . . . . . . 300
Span, i n . . . . . . . . . . . . . . . . . . . . . . . . . . 16.432
Mean geometric chord, i n . . . . . . . . . . . . . . . . . . 18.5
. . . . . . . . . . . . . . . . . . . . . . . .
Aspect r a t i o 0 - 9
Taper r a t i o . . . . . . . . . . . . . . . . . . . . . . . . . 0.665
A i r f o i l section . . . . . . . . . . . . . . . . . . . . . . . 2.5 percent t h i c k
hexagonal
Twist, deg . . . . . . . . . . . . . . . . . . . . . . . . . . 0
Dihedral, deg . . . . . . . . . . . . . . . . . . . . . . . . 0
Leading-edge sweep, deg . . . . . . . . . . . . . . . . . . . 60
Trailing-edge sweep, deg . . . . . . . . . . . . . . . . . . 40
V e r t i c a l t a i l (each semispan) :
Area, sq i n . . . . . . . . . . . . . . . . . . . . . . . . . 20
Span, i n . . . . . . . . . . . . . . . . . . . . . . . . . . 3.868
Mean geometric chord, I n . . . . . . . . . . . . . . . . . .
5.79 Aspect rat i o . . . . . . . . . . . . . . . . . . . . . . . .
0.748
Taper r a t i o . . . . . . . . . . . . . . . . . . . . . . . . . 0.25
A i r f o i l s e c t i o n . . . . . . . . . . . . . . . . . . . . . . . 2.5 percent t h i c k double wedge Incidence ( t o e o u t ) , deg . . . . . . . . . . . . . . . . . .
1.5 Leading-edge sweep, deg . . . . . . . . . . . . . . . . . . .
*ailing-edge sweep, deg . . . . . . . . . . . . . . . . . . -10
Cuter body: Length, i n . . . . . . . . . . . . . . . . . . . . . . . . .
27.5
Fineness r a t i o . . . . . . . . . . . . . . . . . . . . . . . 20.14
Body: Length, i n . . . . . . . . . . . . . . . . . . . . . . . . .
39.50 Fineness r a t i o . . . . . . . . . . . . . . . . . . . . . . .
15.65 I Wing plus horizontal t a i l : S m a l l t a i l Large t a i l
!
Area, sq i n . . . . . . . . . . . . . . . . . . . . . . 360 374 99
Span, i n . . . . . . . . . . . . . . . . . . . . . . . 27-53 28.92
Mean geometric chord, i n . . . . . . . . . . . . . . . 16.43 16.15
A s p e c t r a t i o . . . . . . . . . . . . . . . . . . . . . 2.11 2.23
Taper r a t i o . . . . . . . . . . . . . . . . . . . . . . 0.0986 0.103
I Horizontal t a i l (each semispan) : Area, sq i n . . . . . . . . . . . . . . . . . . . . . .
30 37.495
Span, i n . . . . . . . . . . . . . . . . . . . . . . . 6.244
5.549
Mean geometric chord, i n . . . . . . . . . . . . . . . 6.728
6.055
A s p e c t r a t i o . . . . . . . . . . . . . . . . . . . . . 1.03 1.04
Taper r a t i o . . . . . . . . . . . . . . . . . . . . . .
0.25 0.25
A i r f o i l section . . . . . . . . . . . . . . . . . . . . 2. t 5 percent 2.5 percent
t h i c k t h i c k hexagonal hexagonal
Twist, deg . . . . . . . . . . . . . . . . . . . . . . 0 0
Dihedral, deg . . . . . . . . . . . . . . . . . . . . . 0 0
Leading-edge sweep, deg . . . . . . . . . . . . . . . . 60 60
Trailing-edge sweep, deg . . . . . . . . . . . . . . . . 29.38
29.38 CONFIDENTIAL - A
T
E
cu
T
I
n
\
CONFIDENTIAL 0.0 0 0.. 0 . . 0 .0 . 0 . 0.. 0 . .... 0.. 0 .
0 .
0 0 . . 0 . .
0 0 .
. 0 . 0 . . 0 .0
. . .. 0 . . 0.. . e.. 0 0
0 . 0 .
. .....
0 . .
....
. 0 . 0 .
0.. 0.. . 0.. .... 0..
0 . 0 0 eb&*Mt 0.: .08 .04 Crn -.04 -4 -8 0 .I .2 3 .4 .5 . 6 7 (a) Variation of pitching-moment coefficient and angle of attack with l i f t coefficient.
Figure 2.- Effect of Reynolds number on aerodynamic characteristics in pitch f o r complete model with small horizontal tail (it = O o ) .
\ ......................... . . . . . . .
a 0 . 0 . 0 . . . . ........
.
. . . . . . . . . . . . . . . . ......
0 . 0 . . . . .... 0 . 0 . .
.......... ....... e * a * c D m D E R i ? A z .
" 73 -2 -.I 0 .I .2 .3 .4 .5 . 6 . 7 (b) Variations of lift-drag ratio and drag coefficient with lift coefficient.
Figure 2. - Concluded.
CONFIDENTIAL a , de " 0 .I .2 .3 .4 5 6 .7 -.3 -.2 -.I (a) Variation of pitching-moment coefficient and angle of attack with lift coefficient.
Figure 3.- Aerodynamic characteristics in pitch for various combinations of component parts with small horizontal tail (it = 0 ' ) .
i C O N F I D r n I A L 0 .
......................... . . . . . . .
.
0 . 0 . o m ........
.
. . . . . . . . . . . . . . . . ......
0 . 0 0 . 0 0 0 . 0 .am om.
0 . 0 . 0 . . .... 0 . 0 . .
L D U 0 .I .2 .3 .4 .5 . 6 .7 -.3 , -.2 -.I CL (b) Variation of lift-drag ratio and drag coefficient w i t h li ft coefficient.
Figure 3 . - Concluded.
CONFIDENTIAL (a) Variation of pitching-moment coefficient and angle of attack with lift coefficient.
Figure 4.- Effect of horizontal tail deflection on aerodynamic charac- teristics in pitch for complete model with small horizontal tail.
CONFIDENTIAL ......................... . 0 . . 0 . .
.
0 . 0 . e . 0 . . ........
.......... . * @ I & @ E N ~ L : :* : : : 0 . 0 . 0 . .
16 ..........
......................
(b) Variation of l i f t - d r a g r a t i o and drag c o e f f i c i e n t with l i f t c o e f f i c i e n t .
Figure 4. - ' Concluded.
CONFIDFINTIAL
0 0 0 0 0 . 0 0 0 0 0 0 0 0 . 0 0 0 0 0 0 .... 0 0 . 0 0 0 0 . 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0 0 0 0 0 0 0 0 . 0 .
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 17
o o o o : : ~ ~ r p ~ . . : 0 0 0 0 . 0
.I 2 .04 Cm -.04 -.08 -4 - A - . 3 - . 2 -.I 0 .I .2 .3 .4 .5 .6 .7 CL (a) Variation of pitching-moment coefficient and angle of attack with lift coefficient.
Figure 5.- Effect of horizontal tail deflection on aerodynamic charac- teristics in pitch for complete model with large horizontal tail.
......................... . . . . . . .
.
0 . 0 . e . 0 . . ........
. . . . . . . . . . . . ......
e * . e .
18.e.: .............. *::cob+aTiAI;.. : : ....
" 13 - . 2 -.I 0 .I .2 .3 .4 .5 . 6 .7 CL (b) Variation of lift-drag ratio and drag coefficient with lift coefficient.
Figure 5 .- Concluded.
CONFIDENTIAL
. . . . . . . ......................... e
0 . 0 . 0 .
........ 0 ................ 0 .
. . . . . . . 0 . 0 .
. . . . . .... 0 . .
.................
0 . 0 . & fbErnUfL0
v c , k r, W I CONFIDENTIAL ma. m e o m mom amma o m 0 mom *om am mo m a m o m o m m a e mom a m 0 am mo a m 0 . o m m a momma m a e .
m a 0 omom m o m a m m m amma o m m om. m a 0
(D *
E
.-
CONFIDENTIAL CY Figure 8.- Aerodynamic characteristics in sideslip for various combins- t i o n s of component parts with small horizontal tail Cn -4 L lq# deg (b) a = 4 .
Figure 8.- Concluded.
CONFIDENTIAL ......................... .
. ........ ,. 0 0 . . . . . . . . . . . . . . . . . 0 . 0 . 0 .
. 0 .
................... . . . 0 . ......
.... : : cOKE&&!x: CY -4 -2 0 2 4 6 8 I O BI deg (a) a = o .
Figure 9.- Effect of horizontal tail size on aerodynamic characteristics in sideslip (it = 0 0 ) .
CONFIDENTIAL Cn CY (b) a = 4 ' .
Figure 9 . - Concluded.
CONFIDENTIAL CY (a) a = o 0 .
Figure 10.- Effect of horizontal tail deflection on aerodynamic charac- teristics in sideslip with small tail.
CONFICIENTIAL ......................... . . 0 . . 0 . .
0 .
0 . 0 . 0 . . ........
. . . . . . . . . . . . . . . ......
. . 0 . 0 . . ~ . - . c C l & m ~ k * : : ....... ....
26.'. e * * * 8 , deg (b) a = 4 ' .
Figure 10.- Concluded.
CONFIDENTIAL Figure 11.- E f f e c t of horizontal tail d e f l e c t i o n on nerodymmic charzs- teristics i n sideslip with large tail.
......................... . . . . . . . 0 .
e . 0 . . . e .
........
. . . . . . . . . . . . . . . . . ......
0 . 0 . . . e .... . . . . .
.......... ....... ~ " ~ ~ m I D & I R I , ..
CY B 1 deg (b) u = 4 ' .
Figure 11.- Concluded.
CONFIDENTIAL NASA - Langley Field, Va. L A 1 8