flight measurements of the directional stability and control of a p

UNCLASSIFIED

AD NUMBER

CLASSIFICATION CHANGESTO:FROM:

LIMITATION CHANGESTO:

FROM:

AUTHORITY

THIS PAGE IS UNCLASSIFIED

ADA801234

unclassified

restricted

Approved for public release; distribution isunlimited.

Distribution authorized to DoD only;Administrative/Operational Use; 03 DEC 1946.Other requests shall be referred to NationalAeronautics and Space Administration,Washington, DC. Pre-dates formal DoDdistribution statements. Treat as DoD only.

NASA TR Server website; NASA TR Server website

Restriction/Classification • Cancelled

TED V," ^ ^ < 1 I EM Ho. L6J&5

tl§ ^ ADVANCE COPY . -r**-W——

ayJU^—'

$?-'&si&-g6$~-

CLASSIFICATION1CAHCELLED

Restriction/ Classification Cancelled

RESEARCH MEMORAND for the

Air Materiel Command, Army Air Forces

FLDG-HIT MEASOHEtffiHfS OP THE DUfflCTICKAL STABILITI ARD CCHTROL

OF A P-51D AIRPLANE WITH A HJORS-BALAHC^D HÜDDER AS

COMPARED WITH PREVIOUSLY TESTED VERTICAL-TAIL CGKFIGÜRATIOHS

By

Robert G-. Mungall

Langley Memorial Aeronautical Laboratory Langley Field, Va. --<=

UAMcrt» mean

»»^Restriction/ Classification Cancelled

tfullU • «>(**« »••tip

;^*^l >;V- Äi>

:r--S/ \>r \*

itllj wnm* h« iBfavaa«

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

WASHINGTON

)•—->* Restriction/ Classification Cancelled ^LE

ÜBEBSmCEBR

HASA Technical Llbraiy

3 1176 01437 0960

NACA RM No. L&F25 ««•••(•»

NATIONAL ADVISORY COMMITTEE FOE AERONAUTICS

RESEARCH MEMORANDUM

for the

Air Materiel Command, Army Air Forces

FLIGHT MEASUREMENTS OF THE DIRECTIONAL STABILITY ARD CONTROL

OF A P-51D AIRPLANE WITH A HORN-BALANCED" RUDDER AS

COMPARED WITH PREVIOUSLY TESTED VERTICAL-TAIL CONFIGURATIONS

By Rotort G. Mungall

SUMMARY

Flight tests were made to determine the directional stability and control of a P-51D~20-NA airplane equipped with, a horn-balanced rudder. The characteristics of the. horn-balanced rudder are compared with those of the original production and extended tail configurations. Previous tests showed that the P-51D series airplanes with the original production tail had poor directional stability at small angles of sideslip and had a large change in rudder trim force with speed. The tests conducted on the extended tail configuration indicated that this modification improved the directional stability to the extent of being considered acceptable

The directional stability with rudder free of the airplane wiih a horn-balanced rudder was greater .than that with the original production tail configuration and approximately equal to the value obtained with the extended tail configuration. The directijbnal stability with rudder fixed of the airplane with the horn-balanced rudder was no greater than that with the original tail and was less at higher speeds. The lack of rudder-fixed directional stability resulted in difficulty in maintaining steady conditions at high speeds. No rudder lock was encountered with the. horn-balanced rudder. The. change in trim, force with speed for the horn-balanced rudder was less than that with the original-tail configuration and approxi-' matoly equal to that with the extended-tail configuration. Lateral oscillations. of the airplane with the" horn-balanced rudder were - damped at all Bpeeds except at 130 miles per hour, where a continuous oscillation occurred« This continuous oscillation

NAG A EM No. L&I25

occurred at 25,000 feet altitude was not attributed to the characteristics of the horn-balanced rudder "because the rudder returned to neutral-and remained there during the oscillation.

INTRODUCTION

At the request of the Air Materiel Command, Army Air Forces, flight tests were conducted on a P-51D-20-NA (AAF No. Mt--638£6) airplane equipped with a horn-"balanced rudder. The rudder was fitted with an unbalancing tab as was the original production rudder. Tests were made both with the unbalancing tab in operation and with the unbalancing tab locked. The modification to the original vertical tail consisted of removing the cap from the top of the fin and adding 1.91 square feet of area to the rudder as the horn balance and 0.82 square foot of area to the top of the rudder aft of the hinge line.

A comparison of the directional stability and control characteristics of the P-51D airplane with three different vertical-tail configurations - the horn balance, original production, and extended tail (with unbalancing tab locked)1 configurations are presented herein. The tests of the horn-balanced rudder were conducted at the Langley Laboratory in 19^5 • The tests of the original-tail configuration were previously conducted at the Ames Aeronautical Laboratory (reference 1). Tests of the extended-tail configuration were conducted at the Langley Laboratory and are reported in reference 2.

AIRPLANE

The P-5ID-20-NA airplane is a single-place> low wing, fighter- type monoplane. A three-view drawing of the airplane as tested is shown in figure 1, A side view of the airplane is shown in figure 2 Figures 3 and h show the comparison between the original production, extended tail and horn-balanced rudder configurations tested. Figure 5 is a drawing comparing the rudders of the three airplanes.

General Specification and Dimensions

Engine Packard V-I650-7

Eating: Take-off (6l in. Hg 3000 rpm) horsepower 1500 Normal (k6 in. Hg 2700 rpm) (at sea level) horsepower . . 1000

KACA EM No . L6J&5

Propeller . «_ . Hamilton Standard ByAromatic Diameter 11 ft 2 in. Number of "blades k Gear ratio 2.09:1

Gross weight as tested (at take-off) lb &jk2 Center-of-gravity position (wheels down) percent M.A.C. 25.5

Wing: Span 37 ft -2; in.

16 Area, sq f t 2l«D Taper ratio 2.l6:l Section NAA - NACA low drag airfoil Dihedral, deg 5 Sweepbacfc (leading edge) 3° 35' 32

Vertical tail (production): Total area, sq ft . . . . 20.02 Fin area (exclusive of dorsal fin, sq ft) 9«6l Fin offset from fuselage center line . 1° left Rudder deflection, from fin, deg ±30 Rudder trim tab area, sqft » •• 0.8l Rudder trim tab deflection, deg.... tio Ratio of unbalancing.tab deflection to rudder deflection,.

approximate . . . . right rudder 0.6:1 left rudder 0^:1

Vertical tail (horn balanced): . Total area, sq ft .. = - ..,..'.. 20-75

Note: A.T1 other dimensions-are the Bame as for the production configuration- ...-.•-

WSTRUMSNTATICI*

Standard NACA recording instruments were used to measure rudder position, rudder pedal force, sideslip angle, and airspeed. The airspeed head was a swivel type, mounted 1 chord length ahead of the right wing tip. This installation was not calibrated for position error. Service indicated airspeed Vj as used in this report is defined by the formula: s

vis = 1V5.08 fo^

NACA EM Nö. L6J25

where

f the compressibility correction factor at sea level

q the Impact pressure, measured as the difference "between total head and static pressure in inches of water

The yaw vane for use with the recorder was mounted 1 chord length ahead of the left wing tip.

TESTS, KESULTS, MD DISCUSSION •

Measurements wore made in flight of the directional stability in sideslips and the change in rudder-trim force with speed at 10,000 and 25,000 feet altitude of the P-53D-5-NA with the horn- balanced rudder and fitted with an unbalancing tab« Additional tests at 10,000 feet altitude were made with the unbalancing tab locked. All tests were made 'In the climbing condition (normal rated power, flaps and landing gear up). To maintain a normal center-of-gravity position of 25.5 percent of "the mean.aerodynamic chord throughout •Hie tests the fuselage fuel tank was kept empty* The change of center-öf-gravity'position due to fuel consumption during flight .was negligible.

The directional stability was determined by measuring the rudder deflection, pedal force and sideslip angle during slow continuous sideBlips, in which the rudder was deflected at a continuous rate to the right and left at 'given indicated "airspeeds of approximately 103, 200, and 350 miles per hour at 10,000 feet altitude and 100, 250, and 350 miles per hour at 25,000 feet altitude. Data obtained at these altitudes for the horn-balanced rudder, the original vertical-tail configurations, and the extended-tail configurations are given in comparison in figures 6 to 8 and 9 to 11, respectively. Figures 12 to 1^ are the data for the horn-balanced rudder with the unbalancing tab locked at 10,000 feet* All rudder angles are given in degrees from the center line of the airplane.

• The horn-balanced rudder increased the rudder-free stability but gave a negligible increase in the rudder-fixed stability when compared-with the original tail. A comparison of the values of variation of rudder angle with sideslip d&^/dß and the variation of rudder force with sideslip dFr/dß for all three of the

configurations is given in table I. The value of döy/dß is a measurement of the rudder-fixed directional stability, and the value

KACA BM Ho.. L6J25 5

of dFr/dß is a measurement of the rudder-free directional stability. From table I it appears that the values of dSr/dß for the horn- balanced rudder decreased with increasing speed and at high speed became less than those for the original-tail ccnfiguration. The value of dÖr/dß for all tail configurations tended to decrease slightly in going from 10,000 to 25,000 feet altitude. Because of the difficulty in accurately measuring the slopes of the curves of rudder deflection against sideslip anglo over a small range of sideslip angles, the values given in table I are only approximate.

Values of dFr/dß for the horn-halanced rudder and extended tail showed a normal increase with increasing speed while the values for the original tail decreased as the speed increased from 200 to 350 miles per hour at 10,000 feet altitude. The value of dFr/dß for the horn-halanced rudder waB generally equal to that of the extended tail whereas, the value for the original tail was considerably less.

For the horn-halanced rudder with unbalancing tab locked at 10,000 feet altitude, the value of d6r/dß decreased as the speed increased from 200 to 350 miles per hour. The value of • dFr/dß showed a normal increase with increasing speed. The value of döp/dß was greater with the unbalancing tab locked than with it in operation. This increase is due to the fact that rudder effectiveness is reduced with the tab locked. As expected, the value of dFr/dß was decreased when the unbalancing tab was locked. With the unbalancing tab locked no overbalancing or tendency toward rudder lock was encountered.

Measurements of the .rudder angle and force required to maintain straight flight with the wings level were taken starting from near stall through the speed range. The low altitude test was started near stalling speed at 15,000 feet and the indicated airspeed was increased in a shallow divo until ^30 miles per hour was reached at 8000 feet. At high altitude a shallow dive was started near stall at 30,000 feet until 391' miles per hour was indicated at 20,000 feet altitude. Data obtained from these tests are shown in figures 15 and 16. Also given in these figures are curveB obtained from tests conducted on the original-tail and extended-tail configurations. It was noted that with the horn-balanced rudder the pilot did not keep zero sideslip throughout the dive. and the scatter in the force data is due to the difficulty the pilot had in holding conditions steady. The airplane was not trimmed at the same speed in the three sets of tests, but the data indicate that if .the characteristics were compared under similar trim conditions, the rudder force variation with speed would be the greatest for the

NACA EM No. L6J25

original tall. The horn -"balanced rudder and extended tail configurations would have similar force characteristics except at high speeds, where the extended tail would have somewhat smaller forces. At high altitude, the change in trim force with speed for the horn-halanced rudder appeared to he less than that of the extended tail as shown in figure l6. The pilot had the same difficulty holding conditions steady throughout the run at high altitude as he did at low altitude, thus causing the scatter in the data for the horn-balanced rudder.- The difficulty in maintaining steady conditions at high speeds was attributed to the low rudder-fixed directional stability of the airplane. The change in rudder position throughout the dive, for low and high altitude, is approximately the same, as shown by figures 15 and 16.

In order to determine the hinge-moment characteristics of the horn-balanced rudder, rudder kicks were made in which the pilot abruptly deflected and held the rudder. These tests were made at altitudes of 10,000 and 25,000 feet and at speeds, of 150, 250, and 350 miles per hour. The variation of the rudder hinge-moment coefficient with deflection dCjj/dß was determined from the rudder force initially required to deflect the rudder. The variation of rudder hinge-moment coefficient with angle of attack dOfc/dß was determined from the change in rudder force as the sideslip angle increased. These values of dC^/dS and dC^/da are presented in

table H. From the calculated values, it may be seen that dC^/dce for the horn-balanced'rudder was approximately zero. The unbalancing tab appeared to increase the value of dC^/dS from about -0.007 to -O.OO9.

Lateral oscillations were made at high and low altitude by deflecting the rudder at a rapid rate and releasing it. These tests were made at altitudes of 10,000 and 25,000 feet and at speeds of 130, 150, 250, and 350 miles per hour. The records showed, that the oscillations damped satisfactorily in all runs except those at 130 miles per hour. A time history of a topical oscillation is shown in figure 17- The rudder returned rapidly to its trim position when released and remained there during the oscillations. An undamped lateral oscillation occurred at an indicated airspeed of 130 miles per hour at 25,000 feet altitude. Figures 18 and 19 show time histories of the undamped oscillations. The undamped lateral oscillation was accompanied by a spiral divergence and an increase in the indicated airspeed. When the speed increased the oscillations damped rapidly. There was no tendency for a snaking oscillation, in which the rudder motion reinforces the motion of the airplane. The rudder position record showed that the rudder remained essentially fixed during the oscillation, so that the lack of damping cannot be attributed to the characteristics.of the horn-balanced rudder.

NACA EM Ho. L6J25

This type of oscillation, •which, has "been, observed on other high- powered single-engine airplane, involves a combination of lateral and longitudinal oscillations, and is believed to he caused hy the gyroscopic effect of the propeller. The pilot did not consider this undamped oscillation to be objectionable "because It vas easily controlled.

The pilots considered the control force characteristics of the hornrhalanced rudder to be as good as those of the extended tail configuration and an improvement over the original tail. They objected to the difficulty in ]seeping the directional control steady during the dives at high speeds.

COJCLUSICRS

An investigation was made of the directional stability of a P-5ID-20-NA airplane with a horn-balanced rudder. The results of these tests were compared with those of previous tests of the airplane with original production tail and with an extended tail. The following conclusions were obtained from this Investigation:

1. The directional stability of the airplane rudder free as indicated by the variation of rudder force with sideslip angle was greater with a horn-balanced rudder than that with the original production tail configuration and approximately equal to the value obtained with the extended-tail configuration. Ho rudder loot was encountered with the horn-balanced rudder.

2. The directional stability of the airplane with rudder f lied as indicated by the variation of rudder angle with sideslip was no greater and less at higher speeds with a horn-balanced rudder than with the Original production tail and considerable less' than that with the extended tail.

3 • The change in trim force with speed for the horn-balanced rudder was less than that produced by the original-tail configuration and approximately the same as that of the extended-tail configuration, which is considered acceptable.

8 NACA EM No. LÖJ25

k. The horn-balanced rudder did not cause any tendency for a snaking oscillation.

Langley Memorial Aeronautical Laboratory National Advisory Committee for Aeronautics

Langley Field, Va.

BoUert G. Mungali Aeronautical Engineer

Approved: «^ ) ft /-

Melvin N. Gough '•• Chief of Flight Eesearch Division

mhs

REFERENCES

1. Skoog, Eichard B., ancLNissen, James M.: A Flight Investigation of the Directional Stability and Control Characteristics of a P-5ID Airplane vith Minor Modifications to the Fin and Eudder. NACA MR, Army Air Forces, June 6, 13kh.

2. Williams, Waiter C«, and Hoover, Herbert H.: Flight Measurements of the Directional Stability and Control of a P-5ID-5-NA Air- plane (AAF NO. 1^-13297) with a High-Aspect-Eatio Vertical Tail. NACA MR No. L5E05b, Army Air .Forces, 19^5 •

TABLE I

SUMMARY OF THE STICB>FREE AND STICK-FEED STABILITf AS TAKEN ±1° SIDESLIP

[The condition for which all these values were obtained was clean condition (flapa and gear upjj

Altitude %

a&r/aß dFr/dß •

Original tail

Extended toll

Horn balance

•

Horn "balanced with fixed tab

Original tail

Extended tall

Horn "balance

Horn balanced with fixed tab

10,000 103 0.46 0.93 0.57 O.58 3.55 7-8 4.65 6.0

10,000 200 .55 I.25 .ho •55 7.30 1^.0 15.50 II.7

10,000 350 .31 1.02 .08 .25 5.20 27.2 36.00 29.7

25,000 100 No data .92 •* No data Ho data 9.0 8.5 No data

25,000 250 —do— •98 .43 —do— —do— I8.5 20.5 Do.

25,000 350 —do- .98 .35 -do— —do—- No data to.o Do.

I S3 o

\S\

NATIONAL ADVISORY COMMITTEE FOE AERONAUTICS

vo

• •• • • • • • • ••• • • ••• • • • • • •

NACA RM No. X6J25 ' Fig. 1

76.7' 1 /öfg. *- faf-//ne


Figure 1.- Three view lay-out of the P-51D-20-NA airplane with horn balanced rudder.

S» • ••• ••• •••

• • • ••• ••

• • 8 • •••

>

? oa

•—i DO cn

Figure 2.- Side view of the P-51D-20-NA (AAF No. 44-63826) with the horn balanced rudder.


LANSLEY MEMORIAL AERONAUTICAL LAtORATORY - L ANCLE Y FIELD. VA

I-" TO t

CO

>

en <—i CO CP

Figure 3.- Comparison of a P-51D-5-NA airplane with an extended tau and P-51D-20-NA (AAF No. 44-63826) with a horn balanced rudder. NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

LANGLEY MEMORIAL AERONAUTICAL LABORATORY - LANGLEY FIELD. VA.

9 crq

CO

o >

Oi «—i CO en

Figure 4.- Comparison of a P-51D-25-NT airplane with an original production configuration and the P-51D-20-NA (AAF No. 44-63826) with a horn balanced rudder.

NATIONAL ADVISORY COMMITTEE fOK AERONAUTICS

LANOLEY MEMOmAL AERONAUTICAL LABOKATORY - LANOLEY FIELO. VA.

NACA RM No. L6J25

HORN BALANCED ORtfMAL

EKTENDCO

Fig. 5

0 2 4 6 8 /O 1 I I I I I

SCALE.//VC/J£S NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

Figure 5.- A comparison of the three rudders used on the P-51D series airplane.

I • • I • • •••• NACA RM No. L6J25 Fig. 6

•••• • • • • • •

% 1—

- • "

a Ht f/ r / ?<r, to ne r/ fit 'd 7fc i»- .!i!

- fir t<7i V7l r/ A 'Of rm -? '<>i r m fit HKTA W £ r* ffi flfl ffM\ '7, in ' ( b* f, ffT' rt, ft 9/7

. K-'

Is h.

- j V no - ." 4 ^ *-, '• -

•»* . - .-• •:_ -•r

1 :• ; A k7 JJ\ q •5:

•* •;:

fc \ v, - T.

-s T 0 . ,; S •-:

-,•

, 1 •5 ^ . - ; ,\ r+ '. ii ,s.

V 1 1 ^ I5?*- :.,..

y, y> ^ ^ ^ ̂ n «3 % 1 *&• i^ •: i + t • 4 * ^ \

a ..,":: 4 \ N

?i <m v i

- •K- In, ^ :ct;

~.\- :•".•

:•.-. ^ •0 _'k :Jl Wi

k \ •• •.•-• •.;.. ;:? J"":

" •* r:/

i .;•

v S \ V \ T:

1 •v. si "v ""- u a" P> "> N. • •• ..f.:

^ H n> \ N, 'ft

fO 1 ac at > \ \'t

•-, .n£ <fc N '-. iil

\ j ^ \ •-

1 fi ' \ N \ S V >\ •..•z

11 '! s ^ 0 ,

— \

'S =•-/ <n V s :': •-•

\ \ — .* 4 ^ . .-.: ;l"Z

1 k

v? \ .

** , * 8 K ,

\ \ •n- Y? \

n „ 3i ? -7 •A 7 t > / 7 ? ? •J ? H * !'"•

4 |<» f- R, ffA ^ t- f>f

. ^/ fr r/^ fi Wl rrf ' 1 kj r ., cr_i ?*' ,--: r

ä:"

NATIONAL ADV1S on' f • - ~ii * •--

a HWTTttJOMfKHUUTl« -— :---;- ":•'

Figure 6.- Steady sideslip characteristics at 10,000 feet altitude, climbing condition V"i =103 miles per hour. P-5ID-20-NA airplane with a horn s balanced rudder, original and extended tall configurations.

NACA RM No. LÖJ25 Fig. 7

• • • • • • •••• • •• • • • • • • ••• • • • • • • •

- '-• — — — ... •-

- 1

- — .... .... -• — - — —

-- - — -• - - ! i ... - o Not

s/ alt

T/M

l ?, 3akü5 n. 3 J5

/3S

(W /w 2fa

ta

— .... — — — ... -- .... •--

— --- ~

-1 -• - — — — •- •- - ?*

r 00 .

- — "^

- £

. [

.... — - — •

A to? s \

X - § 1

> -- '•"N

i . 0 t

— 1 CA

\ •^ 02. t N

S 4 KT\ t \ — s •V y\

<? s. i,\ \ V

1 N

s ?, net i c

•o- —I

\ b-< %

\

*, \a 1 ̂ *

— =t? >y

1

k \ V

s, i i

V

w N

felN S^

1 OS s. !

r 1

-• o I

* jN fe -% \

?iJ V *i -— -- \ ^

-S '/? V

$ \, <J \

S

V? \ \5

* 1> n

•s ' r/7 KJ iTIONAL A OVISORY

-T( 7 .? 0 -A 7 1 7 ft ? ? 7 ,7t ? ',= f-/ 9i ?/, /•

1 £/ afe £/ A g i ?- .. .._

Figure 7.- ' Steady sideslip characteristics at 1.0,000 feet altitude, climbing condition V* = 200.miles per hour. P-51D-20-NA airplane with a

S

horn balanced rudder, original and extended tail configurations.

• a • • •• NACA RM No. L6J25 Fig. 8

• • • • • • •••• • •• • • •

•••• • • •

•

-- —

• 3 t hi 7? Gi- •4z.T£i\d /? 'j/fefef-

( w r/4 rr* 'fi in f/t "/ e/>ä t 6tos.& W "YT 'ffi> |7 - —i'jC^ fe 7& 'ea Z25z u 'at '^S

•k T - '

> . . $* V

4 \ i^ A m %

<£» ^ X — SSv

\ ^ > s •fl f> V

y •s k i % X

i ^ T/ 7^ \ V

s.

\ SL

$ X si v. <t "N

V Si k

-? iff; •-

•». 1 <? ^

<* i

f\ — N

X. rs s -

s \

r * \ s N s >ta V s •— ^ V V

KM

* 4 \ - r, S •* V b s s X

\ <J v. s \

• _ 4 \ V

\

ft

V 3 '? .... •

•f. 3 -S f -4 ^ t } i S / s A ?

ft t t ?/ ?A t ."i ftr •<• ffl in T/ f« •ft y

- r MA no •Ud. Alt «IS 3H\

_ LU 5Ü1 it - * «i 1

iUI i res

Figure 8.- Steady sideslip characteristics at 10,000 feet altitude, climbing condition Vi = 350 miles per hour. P-51D-20-NA airplane with a horn

balanced rudder, original and extended tail configurations.

• ••• • • •

NACA RM No. L6J25 Fig. 9

• • • • • • ••• • •••• • • •

-

|r ....

~ - __

- ~ -

3 . I.

tfo ..

I&MA

... _

S£

—

- ._ — ... - ... — -- -- ft, ±A Tki ijtL it,

-- •-• -- - — — - — .... ... —

•t — — -• — — " , - ... 4 m

_. - \

-• - — -•

•-•

-

... - - —

SL ,k

»i :- \

-- ... -- ... - -- w •v

a. £•' — 1 - ...

-• - —

* o

— rt 7f — ... -

^ 0 \ Pfc

- "s \

'«4 ~ - _. —

t \.

vj

I 1 - .... W

- —

... — ^ -& >- et ... -

—

...

z — — - •- ~ - •- -

— - —

-: — — „«< j m

._. " ...

...

-_ ._

- ... " -._ ...

— —

32. N «

- - "

...

- ... —

\ % *; —

- V.

s V

-- .. I.-I 1

-- .„

—

at — r-

*»

v.

n ^ —

— — —

_.. .. •-

t • —

••

—

....

10 - s- r>- —

-" • • —

.... P* I 1

- -i \ —

... ^ s .... - •-

— - —

1 •8 » 0

•£ %

z s —

4 - — - ... —

iv <* ... ... — — j_ 5

n V

-.- - HI

j

V \

1 .

-

•-

— - - — '

_ ?a —

•- — - ...

- * "i —

— ...

/

^ 1 — - m — —

-?i 1 — .=* 0. ...

— 3 J — — J 7 I 7 -- ? ?

~ .L ft .._ - ?A if.

-•

_.. - A

ml PA Tit •ti 7

... - — ... — - — — .... .

- — - — — -

NATIONAL ADVISORY COHMITTK R* AERMUUTICS

Figure 9.- Steady sideslip characteristics at 25,000 feet altitude, climbing condition Vj = 100 miles per hour. P-51D-20-NA airplane with a horn s balanced rudder, and extended tail configurations.


••••

• • •••

- — — — 3 —

*fi r/ ^ T7 W ffl 'f, <?f, 4* ff' 7Fr

.1 • i no tt

1 m a <£ 1

s a •\ v .4

ft :s k o- &

-i off \ V,

\ 3* •i -} fW

=W '

•i.

i t Pit y

s 10

i 1 \

"3 \, > N

•§ ff - *

i ^ <? ffl \

• v \

?fl •

•

« W

-.7 ? -? 1 -ft > ( ' A ) 1 1 1 7 i»f f- ft fff/i *

Sit 'p,v 'r/i n Hj/ •.n AT

TV. HA. If

. A IVI IStC _.. ... — — ^q N4H

»ft V TlCf-

Figure 10.- Steady sideslip characteristics at 25,000 feet altitude, climbing condition V* = 250 miles per hour. P-51D-20-NA airplane with horn

S balanced rudder and extended tail configuration.


• • •••• • •• ••• •

• — —

3 M>r, ? , 3?

4fi trfr

3fl ' 9i //( /ft *-

lOr if = f vt Vfi yirh rf — — Pt rJ u-J tor Tr n/ riTf rn tn ft

k • 1 > w 0.

.

00 «1 i * c K

i« \ (1 a,

•a \ —

(. V %

4 .si 00 ... ... \ * V %

-% -z1 00

— •

• 1 j •

1?

-•

fi t t

<$ i

N

4 S ••

' % •? S

1 . 1 K i

0 3& —t ;> '•

s "U L e > — \ i •4 \

£ \ •_

V s

- •fi

<i

< 1? :

/ • d '. < t i 1 t

r i

Si *< (t/i ft tftf fj •o

-u NATIONAL AC VIS

EDO on uir ncs-

Figure 11.- Steady sideslip characteristics at 25,000 feet altitude, climbing condition Vj =350 miles per hoi

balanced rudder and extended tail.

condition Vj = 350 miles per hour. P-51D-20-NA airplane with a horn


• • • • • • •••• • •• • • • • • • ••• • •••• « • • • • •

.A —

-•

. .

...i.

t

-I---

•

1 -

r 4 i t r

--!• i

1 .'..

!

..U

r '

_1. i

—i- - •-. !

L

1. J

i

Alat, •cTtoi \

fj" Or

!

-

•ztiie ucfyft Fat.O. fctqd ..I.

i i

~r " i "

i

i

-i 1

' -1

V\ 'o/iftt L i

' t i

1 ii.:

i i t

\

i

" 1 i I

i ...

. i

••!•"•

ons . 1-

1

1 !

-J 1

1

1

...ii

T ! • i

+• i • V

1 1 3

is

0

1

©

. ..: .. _. ^ _ !

-1.•

V- —

- " " —

' '"

_ ....

"~ -

... ... i

( "'" • ... I- i

j

" i 1

•e- ij — " " ... .... .

•

. .

.1 -- •

1 •" ~^ "

— ( > J& ^

\ ! •

•- - j ... —

_. L l — ?a

— —

1 __

-- •-

... "o| Iff

- • - - 1

1« —

... - " - i

l

i i "L

-.4 . 1

-•

c L. ! 1

i , i T

-r 06

1 .. .

i i.. i

~J\ i

i i

i . •- - — 1 I

-- 1

— ....

....

•~~

-•

* i

— 1

.

...

~

... •- ... ....

-

— • -i

•-

. Ttf k 1

— •9 's, V J i» 1 k -!•

• i"

V ' \" -+-

i

^ >>J -. -4- i

_

-•

j_

- — -

—j W ...

... --

—

[

- , i

• • i ! " i

1

•1 1

1 •r-i

i "J>

— --

— — .... —

--

— 3 _

'Q ... ...

•-

i "i"

1 [ •

-- — "i — — —

— O

'O

• 1

i

— —- ... _ ... 3^

i ... _3i

— " i ' r

-•

t i.

...

-

T

t

' !'" ... •-

... - --1 - - — ... i

—

— ...

'-

. — — — - ...

•i— _j

i —

" .... •-

i- ... -- -f Y7

•-

- — i ... ... 1-

_., u 1

-T3 rr? — -- - -- ... -• ~- - — ... ... •- - -

..... -

•f

- •j V. ... — •- -- —

. _ — - ... — — 1

:l: . i. .—i...

! I

— -- •A 2. ~ -yi ?_ t > A ? — .2 f> 9, --

_•.

t -- ... 7if '*-< ̂ 7 w %l & ?- i r

- \

NATIONAL ADV K1 4- _. 1 ! \ . COMMITTEE FOf AEBOMiUDCS

Figure 12.- Steady sideslip characteristics of 10,000 feet altitude, climbing condition V^ = 103 miles per hour. P-51D-20-NA airplane with horn

balanced rudder with tab locked.


••• • ••a

—

-_ -

•—

—- —

. •-

—

....

... - 1

T to

Tat de i.fat

ni r<

•L.

yarn/ •aa ..: -~ .._

— . - _i Tai tos

rn ,4" 'm

— — •-

-- cu du

*MI Ctf

— - -

— rf/ M Or Ex i

- •

1. — — — ... •-

... — ?0f,

-- > - «? — ...

s

...

i

.._ •-

'S f/Wi — -

{ ... •- — i _.

._ ... -

— ± i

3 — •-

— f s f> V n a — --

... ~ ~

* -- ^ '< \-} OCt

-•

--

5 &

- _.

— -•

... — -- •k.

... — 1

— ....

a -} Of, —

— — - — t rn - — •- '1 — -•

$ — - *n .... mrJ —

— — — * -- 'O ^ — — —

r S j .... - — .... * A r, V

*<1 * - — — ,« &

— — ^ <J _^ v?

: ;

*n — — •s.

* ><| 70 i

— -T ? • r>, 7 -/. ? 1 ? f< ? 2 9 — ,1, ? i '(«»i *h 9* at V

frr fr" ^ 7 t I/If '/ft rfi iff N AT ION AL ADV SORY

-•- _- _.: *"j "'J^i*"". .—>

Figure 13.- Steady sideslip characteristics at 10,000 feet altitude, climbing condition Vis = 200 miles per hour. P-51D-20-NA airplane with a horn

balanced rudder, tab locked.

• ••• • •••


• • • • • • •••• • •• • • • • • • ••• • •••• • • • • • •

B( tf7 "V? /<? r/1 r/j ffl r/ 4>f rrti I«- r • ••:

— -,

> •

| ' ? ft/) •

-.•

- 1

f fX) Hi

\ H: ."•"•

} , * r

•ffl 1/ ft 1 -5 ':- .

'' -1 V

QJ *&. n ,.

%J -? <ia ., ^» J -~: •:

f

'

:

% !...• • ;

1 » A ._. - .' T

— — .: 4 — ~ • I •-:

b • •JE •» 0 *? 1;t

I \ ! 5

•4 •,

' ['i

i -fl S --" • :

..,- . T- ",: f • '•M

• •-,

1 1 . t 1 7 •• £ 1 t •

.«?< iff till it [ffj fr K* • : •r .

.... 3HH

iTlÖN» Li DVI son Y . c rrn I F 01 J tuo «Ul TICS

1

Figure 14.- Steady sideslip characteristics at 10,000 feet altitude, climbing condition Vi_ = 350 miles per hour. P-51D-20-NA airplane with horn s balanced rudder, tab locked.

• •«

• ••

• •a«

•••

NACA RM No. L6J25" Fig. 15

" -- — - — •-

3/1

•/«"

- - — fp \ V

$ ISI >s

... s-

Fi a. M

V r

\ \ * * i" /r '/> af t, a \ - | tu 7/t >at J. te •& <* 7C te 1 fl N s

1. -u ^ >N - - - "fcj

">1 1

* ^ < 4 ^

0 .... ...

•: «: < -? 6 ^ & -B — iC ...

(}

- - -- 8= ce

< •k .... -*

4 - s — - — —

— ._•- - -- ~ —

- — — -• -•

... ... - ... — - — / ntf

— -- .... - —i —. - - - - \ \ .._. - / 'ft \

- 1« •\

^ ^ >, - - - . f V? o^ ^v

... •«,

^ ̂ - - - — — - >o .a. 9>

Ng

"v -» -- - •- - - r . J, '•si > ^_. >& *-. ^

•

^ ̂ ""5. *. .._ - - ^s »^

o" -, •^ r 0 f

s $ \ 3 •^

V E> *N Jl \J

—d *a ... o Q ler ""^ - S

kj . — — r •v

H "v --, ?>

i*

* ... ... ... >« -t w - O^ \ ̂

— — N, O ^

<P N — - - — ... - k

-f ?0

?} vr - •

t \o n Y? ft ft ?( W a WT~ — ?; 1*7 ?J id •4, W

- Vr fl *rf fr, A

— ... >r M \ftt / T/V V

•

~r" •

t AT ONAL UVISG RY ?*j fUT] F« rot <£> out UTIf rS

Figure 1&.- Rudder trim, force characteristics in diving through the speed range from .14,000 to 8,000 feet altitude. P-51D-20-NÄ airplane with horn balanced rudder, original and extended tail configuration.


• • • • • • •••• • ••

•••• • • • • • •

••£•••

•• ... • - .. „ — f?.

1 y 3 Han-, / (7/ 7/ rv f//r /n 'r/t '/- 1 \ — £j£A>.o tf= V ?R f/ /: M /; mtr-.r-rt/ti

\ A V

V s ̂

s •*. \

s i 4- •^

? •* V s * "»s.

* "\o 0 D_'

^ ! ff 1

t .4 -

— — TA

'?

?fl

1 if M

~ -r -

s .! 40 s «Ä

— V ^

s e w V

-•iS fl * w i —s vS

p>

-1 n n

*« % ^ 40

""*•

— - I «V* -^ qgt

&L

•% 30. -s V :

7(1 s

fl 7 /, 0 II 0 ? W ?( W Pi W ,T W vT Yf -ft If V; ,<? °r Wi Ofl fa f t in M •rf m \/r '<

jn

... - •-

COHWTTU FM MJIOJUUTICS

1 1 1 1 1 1 1

Figure 16.- Rudder trim force characteristics in a dive through the speed range from near 30,000 to 20,000 feet altitude. P-51D-20-NA airplane with a horn balanced rudder and extended tail configuration.

• • <_


• • • • • • • •• • • • • • •

9 •

- -.-•

,:- - -il- -.:•. ,.., _

'-.- •'.-•

>;-." _•-•

.;:,:;•-" i-; •:.-' .;•

0 .-; ''•

.-' ~. •2% _,..

j;--:

•-• -.-•:• ^"r :"'•"' .... '•2: • iV' .•:..-.

- "1 - '.* ';;-•

•ij'i • .':.'..

/ - •

:T K>v-: ^ _^i.

••- • ::

F 1 A -4

/ -•-": •:i:-

:-' ' "*•

-v. :^ \ :'„,. •::'' / ,':':. ::: '::-i':' • H--.

•-L .. • 'r-^: i;:'- ''if; •if:' •it

i —' .-. .; : "- •

'."'•'

::.:• .... '•':..

-i: ^ r^ •"- •"." : '•.

•--. . -.. '— J±:i' >.-t':

-03 "*\ .:: •iP "^ - -'- • "-.+•,- • .''": ^5-'

-. .. r. -H •••:- v;

. '•:'- •::-.

>;'• :_': •:•„ :~ '.:. -•s.. _•-• '^

--•i 1 ,<- "•-•

•; L^T '--.' 7-L' 2 ;';"-- -i^-i

m :-• L: .- -!"-T •^," .":' ; '•'-• •T*.V : •:'•

•'-• ';";:- •'-•::

..-. .,--' --:- .;.': .-f*r- r."

rl':' ••/.;-. •X-k '•-

•':- •_ "- •.:;:

:-. ::.-: ::. :-i" Qj

^ ;. l •-.'

.:- ;._ j.. •:-:-' r. V,', • Z: .... ;i% •§•: ~j~'i

^ ~Y 0 '•- .-.-. -- 'V T.-- -":. •,..-.-.-

:••'• " j."T^ .-:':'••- i'r:

fT

-Hi •i-'-'- •*-r*A

••::; :\iü

.- . :. ? -'. .;." - " "•'•

* *." ~ i:':-- :-- :i~ ;!j_^ •:-\ r±r ' "'-

** "• "•

:'••;-. -" ..";"'-" ::r'' •':• :V- - - ."-r- !^.v ~ii JJJU

- ;••- -i 00 i- -V -

•':-•

.:•:"• •-.v.- ."•r Üt> •-•"• ?•'. •S: •*-: "~ :'-"j/ '•-'•

:-- £; i:: •<?:. r...- . :•-.- •'.'" ..:•" .7: + '•r- i"/ " ".'.V ] ;:::"- : T ; - •&•

.::.. ß . •' ' .'.:• •:•/.- •••:- --: •ir_r.

rr~- :-r- ;."

\ •:.'

"" :f" ^ ij.'--* •1:J ' :••••"'

.;- ":'r.- v.Z .•-«•if

#: IV .;•-•:•

THT :rr:. •

•.:'-. :£ :'-• - J

:':'. ,-.•: - ;;- -:-.- -J". l-i-d • --

.;'. :""•

"l."" v--. -:.": •_ T.;

v ,--• S: '- ^fe ,:••

4 : •' -.:-.

:•.'"• t. -':- r,; V-J-" -,-:-f- :?":: c. :i<::. .'\ij

:& M ::-:." .

^ y.-- ---.

:•'•?' •;••:.'

Si .4t- •:-rt-i"

4: .'"• '•:•:. "± -.-•:

:-: ;'..' :•:•.

•-''•

.-+; •j$k: -.3;

:S3 V :TJ -.- :£.•• •~ •:••'

NATIONAL ADVISORY ^ •!#'

V S •> 1' V? -.."•

:•:•-•- .- •..•

;•!-.• ••'- •>V HKI lit •:-:

«jB EKUI »AU I(_i t". -,. •^T

•H ?a '.--'••

' .•':' i-§- r •-•-•j.

::.:•-: 'r':'. fe'v •tr*

"r*:

r$ -:.. ::• :il. '•'-"

•••••:• V. ••:.-.. :•'•:• ^

- ft ,;•: -•::. .,"l;1 J.*:

•-:.

• "L^-

•?•?.. '-':':• i i" r

,'.:il

'--•'

•4 P '••. -.7> r:' . 1^^ ^x-.- •_? -. . -.: . ~ ."r :^: -.rr:

;• ( r / •- . '* L V ? 1 t •*t ^ i.i"

. 1 7m r ,1 ec

Figure 17..-. „AJypical right rudder kick at 11,000 feet altitude, climbing condition Vj_ = 150 miles per hour. P-51D-20-NA airplane with

horn balanced rudder having the unbalancing tab locked.

» • • • • • ••• ••• *•• • » • • • • • •

! j- -~r~ r I I ! 1 1 1 i

—i i— —1 <— "•;

•• 1 j • i

| j i i *

1 1 1 j i -

i i i ! 1 r ! i i • 1 • .| ;

i 1 i 1 i i

si # w •I I i ' i

*1 : i

—i— -4• i i i 1 .

! —i— ^-L 1

Hh i i—|

1 i — rh — =^t= H P ba 1 i 1 1 ; I

i . i ! !/? 1 ] 1 i ; | • 1 •

1 i |

... - i 1 i i i ! ! 1 Lr i i

i i i ! L_^ _J_ i i i

$ ! • n . i I ! ' 1 l .3 H |\ n i

i —f •

1 i

i C It 1 I" •

1 / l-"1 \ i l

i «5 / > /

* i ,

f- / v •

\ r ! v. i** i N k / V V r y r \

1 i 1

. i rt m 1, i >• ; I i •

I1 *" i

1 i S i

' i i i 1 i ..

i% a 1. • i i 1 ^ I il_

|—!—"—•—'•• i i — ~ i i

—i— !

$ i i V , i i i! i i

^ i \ 1 i

i ! ' i

11 j i

i ,<m i i 1 i | 1 I i 1

. i i i 1 ! 1 i i

i _4^ i i 1

/ i —i i—i—i

S' !* : l l i |

•£j i 1 —i i

il i Icwwrre ret UWMUTICS 1 A <i i •• 1 i

i • * ̂ 4 t ff 1 A \ //j 1 /? 1 # /t ' /, * p 1 ?s p-t

i, i i .i | i i 7?, s» u fltf, . T • , i-j

Figure 18.- Rudder kick to left at 25,000 feet altitude, climbing condition Vj = 130 miles per S

P-51D-2Q-NA airplane with horn balanced rudder.

hour. 00

• •• •••• •• »* • • • • • •• • • • • »>• ••• • • ••• • • 1» •• • • • • • c

' . i

?, m - -,

* — — —

n

n ft ? s •

* \ •4 f 1 1 r" /

,« • •

1 f

1 \ i / 0

ft ,t y

V s • A m ;

4.

1 f \ jj

* =5 n ^ " k 1 >

r/f V) .... -

t '? \ r- - .

"t , iBV

«IK

sn HU i > M A¥I

EE U- J W

5 1> ö '•L jun ill

1 \ *—•

"*•

if *f i =

i » i i ? \ < ••/ 1 A 7 {\ 7 A £ /> - tf j ft TU u a ->

Mgure 19.- Rudder kick to right at 25,000 feet altitude, climbing condition Vis B 130 miles per hour. P-51D-20-NA airplane with horn balanced rudder. CO

ATI-71 183 *Z* 6--Ar4V< *3

Langley Aeronautical Lab., Langley Air Force Base, Va. (NACA RM L6J125)

FLIGHT MEASUREMENTS OF THE DIRECTIONAL STABILITY AND CONTROL OF A P-51D AIRPLANE WITH A HORN-BALANCED RUDDER AS COMPARED WITH PREVIOUSLY TESTED VERTICAL-TAIL CON- FIGURATIONS (RESEARCH MEMORANDUM ), by Robert G. MungaU. Dec 3, 1946. 27 pp.

(Not abstracted)

f ^ 4 DIVISION: Aerodynamics (2) SECTION: Stability and Control (1) PUBLISHED BY: National Advisory Committee for Aeronautics, Washington, D. C. DISTRIBUTION: U. S. Military Organizations request copies from ASTIA-DSC. Others route requests to ASTIA-DSC thru AMC, Wright-Patterson J^Mbrce Base, Dayton, O. Attn: NACA. ^B

SECURITY INFORMATION

I. MungaU, Robert G. Ü

ARMED SERVICES TECHNICAL INFORMATION AGENCY

DOCUMENT SERVICE CENTER

J>yj.//7fs

flight measurements of the directional stability and control of a p

Documents