UNCLASSIFIED

AD NUMBER

CLASSIFICATION CHANGESTO:FROM:

LIMITATION CHANGESTO:

FROM:

AUTHORITY

THIS PAGE IS UNCLASSIFIED

ADA801410

unclassified

confidential

Approved for public release; distribution isunlimited.

Distribution authorized to DoD only;Administrative/Operational Use; 05 AUG 1947.Other requests shall be referred to NationalAeronautics and Space Administration,Washington, DC. Pre-dates formal DoDdistribution statements. Treat as DoD only.

NACA research abstracts no. 57 dtd 29 Jan 1954;NASA TR Server website

;• ^aoMrmFT-^rrAT?-

Copy Mo. 4

RM No. L7F16

" 1

RESEARCH

LANGLEY FULL-SCALE-TUNTS[EL'®VESTIGATION'QF.MAJgMUM LIFT

AND STABILITY CHARACTERISTICS OF-AN AIRPLANE HAVING

1 APPROXIMATELY TRIANGULAR PLAN FORM (DM-1 GLIDER)

By

J. Calvin Lovell and Herbert A. Wilson, Jr.

Langley Memorial Aeronautical Laboratory Langley Field, Va.

CLAJ9UI? LED DOCTWUTT CLASSIFICATION CAr

This docioMnt ir"nt*frff cJudfitd isfonsifctsii •flMtiov Uw Htilotna Data»* at tbt U^tfrW/kvUu Stats* wflhfa tha naasEi« of tha Kaptoaa«*IttjMWrIt J USC EOiSI ml 3*. u iTiuaanUalm er tha revaUttea of LU *****—*- In injr usntr to an anirfaorLMd pan« 1* prohibited tqr l*w. Information ao oUsatfled may b* Imparted

oaty ta paraona La tha. military —" * Barries* of m* Ualtad Stetes, aWUiui offlaax« ud m&aj*** of Gmnnai who btv* a iatflimata loteraat Iterate, and to UnitedStita*citizens*known toyiltr Md dfjcraUo&wbo of Daeeaaftr ma* ba tafQTmtd tbaraot.

-—. .£>£:.J.üA.T6fA'L

„.(LUlUSC

5 r c 4 v..- -.

^•v J

c?e ^X

/

NACA EM No. L7F16

NATIONAL ADVISORY COMMITTEE FOE AERONAUTICS

RESEARCH MEMORANDUM

LAWS-LEY FULL-SCALB-TUHML INVESTIGATION OF .MAXIMUM LIFT

' AND STABILITY CHARACTERISTICS .OF AN AIRPLANE HAVING

APPROXIMATELY TRIANGULAR PLAN FORM (DM-1 GLIDER)

By J. Calvin Lovell and Herbert A. Wilson, Jr.

SUMMARY

An investigation. of the DM-1 glider, -which had approximately . triangular plan form, an aspect ratio of 1.8, and a 60° sweptback leading edge, has "been conducted in the Langley full-scale tunnel. The investigation consisted of the determination of the separate effects of the following modifications made to the glider on its maximum lift and stability characteristics: (a) installation of sharp leading edges over the inboard semispan of the wing, (b) removal of the vertical fin, (c) sealing of the eleven control -balance slots, (d) installation of redesigned thin vertical surfaces, (e) installation of-faired sharp leading edges, and (f) installation of canopy.

The maximum lift coefficient of the DM-1 glider was increased from 0.6l to 1.01 by the installation of semispan sharp leading edges, and from 1.01 to 1.21^ by the removal of the vertical fin and sealing of the elevon control-balance slots.. The highest maximum lift coefficient (l«32) was obtained when the faired sharp leading edges and the thin vertical surfaces were attached to the glider.

' The original DM-1 glider was longitudinally stable. The s'emi- span sharp leading edges shifted the neutral point forward approxi- mately 3 percent of the root chord at moderate 'lift"coefficients, and the glider configuration with these sharp leading edges attached was longitudinally unstable, for the assumed center-of-gravity location, at lift coefficients above 0,73« Sealing the elevon control-balance slots and installing the faired sharp leading edges, the thin vertical surfaces, and the canopy shifted the neutral point forward approximately 8 percent of the root chord.

The 'dihedral effect of the DM-1 glider with the vertical fin removed and eleven control-balance slots sealed was positive for lift coefficients up to O.f» The semispan' sharp leading edges extended the lift-coefficient range for positive dihedral effect up

UNtt-ASSi^'

NACA EM No. L7F16

to a lift coefficient of 1.0. The faired sharp leading edges, which increased the angle of sweepbeck 4.2° reduced the highest lift coeffi- cient for positive dihedral effect to 0.7»

The configurations of the DM-1 glider /with no vertical fin had a small degree of directional stability at low lift 'coefficients and became directionally unstable at the higher lift coefficients. The thin vertical surfaces installed on the DM-1 wing having-elevon control-balance slots sealed and semispan sharp leading edges attached contributed an increment of approximately -0.0024 tö 0^., thereby

giving positive directional stability at all lift coefficients. The faired sharp leading edge and the P-8o canopy had destabilizing effects on C« .

The results indicate that airplanes having approximately triangular plan form with 6o° cweepbaclc and sharp leading edges can be designed to have acceptable stability characteristics in the subcritical speed range.

HJTE0EUOTI0N

Research directed toward the attainment of supersonic flight has led to interest in the characteristics of wings of high sweep and of low aspect ratio. Since there are only limited full-scale data on such wings, an investigation of the German IM-1 glider has been conducted in the Langley full-scale tunnel. The DM-1 glider, which was designed for the investigation of the low-speed characteristics of an airplane configuration believed suitable for supersonic flight, has approximately triangular plan form, airfoil sections similar to the NACA 0015-64, an aspect ratio of 1.8, and a 6o° sweptback leading edge.

Preliminary tests of the DM-1 glider in the Langley full-scale tunnel disclosed that the maximum lift coefficient was considerably lower than had been indicated by low-scale tests of similar configu- rations. In an effort to increase the maximum lift coefficient, the effects of sharp leading edges, redesigned vortical surfaces," and other modifications to .the DM-1 glider were investigated. In addition to the maximum-lift tests, an investigation was made of the stability and control characteristics of those glider configurations believed most suitable.

The results of the major part of the maximum-lift investigation have been presented in reference 1. The present paper gives the results of the stability and control investigation and also includes a brief summary of the maximum-lift results.

NACA EM No. L7F16

SYMBOLS

The data are referred to the stability axes, 'Which are defined in figure 1. The moments are given about center-of-gravity locations assumed to he at 50 percent of the root chord. (See figs. 2(a) and 2(c) .) The wing area of the original 3*1-1 glider (215 s

NACA EM No . LTF16

p mass density of air

V free-stream velocity

3R Reynolds number

S wing area

C-L root chord of glider configuration 1

c' mean geometric chord of wing (S/b)

"b Bpan of wing

"be elevator span, feet

ce elevator roo.t-mean-square chord "behind hinge line, feet

C7 rate of change of rolling-moment coefficient with angle * of yaw, per degree

Cn rate of change of yawjLng-moment coefficient with angle •^ of yaw, per degree

Cy rate of change of lateral-force coefficient with angle ^ of yaw

a angle of attack (measured in plane of symmetry), degrees

t % angle of yaw (positive when right wing is back), degrees

Vd5e. ,_ , rate of change of pitching-moment coefficient with

*. e/^ _0 elevator deflection measured at 5e = 0°

&e angle of elevator deflection (positive down), degrees

bf angle of flap deflection (positive down), degrees

TEST AIRPLANE AND MODIFICATIONS

The DM-1 glider was designed in Germany for the investigation of the low-speed characteristics of an airplane configuration believed suitable for supersonic flight.

NACA BM No. L7F16

The EM-1 glider has an approximately triangular plan form, airfoil sections similar to the NACA 0015-öf, an aspect ratio of 1.8, and a 6o° sweptback leading edge. It was constructed almost entirely

of wood, the skin was -i-inch three-ply "birch plywood, and the spars

and ribs were of conventional bos-beam construction. Hie principal dimensions of the glider are given in figure 2 and table I. General views of the glider mounted in the Langley full-scale tunnel for tests are given in figure 3. The glider as received was equipped with a rudder for directional control, elevons for lateral and longi- tudinal control, and longitudinal trim flaps. The "balance on the control surfaces was of the elliptical overhang type. The "balance gap was relatively large, however, and the shape of the wing Just ahead of the balance gap was elliptical. (See fig. 2(h) .)

Following the basic tests of the original IM-1 configuration, numerous modifications were made to the glider in an effort to improve its aerodynamic characteristics. These glider modifications, which are referred to throughout the present report "by configuration numbers, are sketched in figure h and are outlined as follows:

Configuration 1: Original EM-1 glider. (See figs. 2(a) and 3(a).)

Configuration 2: IM-1 glider with semispan sharp leading edges attached. (See fig. 2(b) .)

Configuration 3! IM-1 glider with vertical fin removed.

Configuration ^: IM-1 glider with vertical fin removed and elevon control-balance slots sealed.

.Configuration 5: IM-1 glider with vertical fin removed, elevon control-balance slots sealed, and semispan sharp leading edges installed.

Configuration 6: Same as configuration 5 with the redesigned- thin vertical surfaces shown in figure 2(c) installed. These vertical surfaces were, for simplicity of construction and installation, made with rectangular sections three-quarters of an inch thick.

Configuration 7 '• • Same, as configuration 6 with the faired sharp leading edges shown in figure 2(c) replacing the semispan. sharp leading edges.

Configuration 8: Same a's configuration 7 with the P-80 canopy added. (See figs. 2(c) and 3(b).)

NÄCA RM No. L7F16

METHODS AMD TESTS

The tunnel airspeed for the testB was limited to approximately k5 miiee per hour because the structure inside the glider, vhich was available for connection with the model supporting struts, was exceedingly fragile. The tests of glider configurations 1 to 5 were conducted at'this airspeed, which corresponds to a Reynolds number of k>6. x 10° based on the mean geometric chord of glider configuration 1 (10.97 ft). Buffeting of configurations 6, 7, and 8 necessitated.a reduction in tunnel airspeed for tests of these configurations to 36 miles per hour.

In order to determine the separate effects of the component parts and modifications of the DM-1 glider on its aerodynamic charapteristies at zero yaw, the forces and moments on each glider configuration were measured throughout the angle-of-attack range with ail control surfaces locked at 0° deflection. Tests were conducted for configurations 1, 2, and 8 in order to determine the effect of the semispan sharp leading edges and of the modifications of configuration 8 on the elevator effectiveness and on the longi- tudinal stability.characteristics of the glider. The elevator hinge moments and the effectiveness of .the trim flaps of glider configu- ration 2 were also determined. The lateral stability characteristics of glider configurations 3 to 8 with control surfaces neutral were investigated by determining the aerodynamic characteristics of each configuration at angles of yaw of approximately 0°, ±3°, -5°, -10°, -15°, and -20°.

RESULTS AND DISCUSSION

The results of the DM-1 investigation are summarized in figures k to 10, and the basic data from which the summary figures were prepared are presented in figures 11 to 21. An index to these figures is given in table H. All the test results have been corrected for the effect of the Jet boundaries on the drag coeffi- cient and the angle of attack. Wo correction has been applied to the data, however,, for the effect of the Jet boundaries on the rolling-moment coefficient or for the tares of the model' supporting Btruts, which were found to be of negligible magnitude.

HACARM Wo. L7F16

Maximum Lift

The summary i-esults of the maximum-lif t investigation of the eight EM-1 glider configurations are given in figure h* The maximum lift coefficient of the original EM-1 glider (configurat'ion l), was increased from 0.6l to 1.01 by the installation of the semispan sharp leading edges shown in figure 2(h) . These sharp leading edges induce vortex-type flow over the upper surface of the wing which delayB the stall to much higher angles of attack. (See reference 1.) The maximum lift coefficient of the glider was also increased from 0.61 to 0.93 by the removal of the vertical fin. The maximum lift coeffi- cient • of the glider with vertical fin removed (configuration 3) was increased from 0.93 to I.08 by the sealing of elevon control-halance slots, and from I.08 to 1.2k by the installation of the semispan • sharp leading edges. The addition of the redesigned vertical surfaces to glider'configuraticn 5 increased the maximum lift coefficient from 1.214- to 1.29- The highest maximum lift coefficient measured (l«32) was ohtained for glider configuration 7, which had the faired sharp leading edges-and the redesigned vertical surfaces installed. The addition of the P-80 canopy to glider configuration 7 decreased the maximum lift coefficient to I.27. The aerodynamic characteristics of each of these eight DM-1 glider configurations,, throughout the angle-of-attack range, are shown in figure 11. • •

The effect of yaw on the lift characteristics of glider configu- rations 3 to 8 are also shown in figure 11. The lift characteristics of glider configuration 3 were not affected in any systematic manner by angles of yaw up, to -9«9°. The lift coefficient at any angle of attack was, however, decreased somewhat by yaw angles of -11*-.9° ' and -19.9°. As the maximum lift coefficient of the glider was increased by the modifications of glider configurations it to 8, the lift coefficient became increasingly dependent on yaw angle. The lift coefficients at an angle of attack of 380 and zero yaw for glider configurations k, 5, 6, 1-, and 8 were decreased by incre- ments (&CL) of 0,12, 0.13, 0.26, 0.37j and O.39, respectively, by -9.9° of yaw. •

..The effect of tunnel velocity on the lift coefficient of glider configuration 2 is shown in figure 12. These data were obtained at tunnel velocities of 29 to 52 miles .per hour, which correspond to Reynolds numbers of 3.0 k 10° to 5.3 x 10°, respectively. The maximum lift coefficients measured at these Reynolds numbers indicate that the reduction in tunnel velocity from lj-5'to 36 miles per hour, which was necessary for the tests of glider configurations 6, 7,- and 8, had no appreciable effect on CT

8 «••MpMfa NACA EM No. L7F1Ö

Longitudinal Stability and Control

Longitudinal stability and control, stick fixed.- The stick- fixed static, longitudinal.stability and control characteristics'of glider configurations 1, 2, and 8 for the canter-of"gravity locations assumed are indicated by the curves of figure 5. These results, which give the elevator deflection for trim at various lift coeffi- cients, were obtained from the curves of figures 13 and l4. The rate of change.of elevator deflection with lift coefficient for ' configuration i (original DM^-l glider) indicates stable elevator- control movement throughout the lift-coefficient range investigated. Glider configuration 2, which had the eemispan sharp leading 'edge attached, is statically stabie up to a lift coefficient of 0.73, above which the elevator deflection for trim is in the unstable direction. Glider configuration 8 was statically stable for lift coefficients up to O.87, above which elevator-effectiveness, data were not available. The variation of C^ with CL for configu- ration 8 with controls neutral, however, Indicates that this configuration has static longitudinal stability for lift coefficients up to 1.25.

The static longitudinal stability characteristics of configu- rations 1, 2, and 8 for any center-of-gravity location can be determined from the curves of figure 6, -which show the center-of-gravity locations at which the longitudinal stability is neutral when tho glider is trimmed- TIB location of the neutral point of configu- ration 1 moves rearward from 0.5200-^ at C^ = o.l to 0>5k6c^ at C^ = 0A6. The vortex-type flow induced by the eemispan sharp

leading edges of glider configuration 2 shifts the center of pressure of the wing forward, decreasing the static margin, so that less elevator deflection is required to trim oonfiguration 2, as was previously indicated by the curves of figure 5. The neutral point of configuration 2 .is at O.Jpl^c^ at lift coefficients up to 0.5,

and above this lift coefficient the neutral-point location moves forward with increasing lift coefficient. At lift coefficients above 0.73, the neutral point is located forward of the center of gravity, making the glider unstable. The modifications of glider configuration 8, which add I6..9 square feet of area at the leading edge of the wing, move the neutral point forward to approximately O.V75C-L. This point, however, corresponds to O.530 of the root

ohord of configuration 8, so the configuration Is longitudinally stable, for the center-of-gravity location assumed fo.50 of root chord)•

It is of interest to compare the neutral-point locations of the DM-1 glider with the theoretical neutral-point location for a •wing of similar plan form. Falkner has made calculations (reference 2) -which show that the neutral point of a delta wing (equilateral triangle with apex forward) is located at 58 percent of its root chord, which point corresponds to 50.6 percent of the root chord of the 3X4-1. This result is in good agreement with the neutral-point locations of DM-1 glider configurations 1 and 2, which, have plan forms approximating an equilateral triangle.

Elevator effectiveness.- The results of the elevator-effectiveness tests of glider configurations 1, 2, and 8 are given in figure 7, which

'dCL\ shows the variation of ( TT* ) • with angle of attack. The elevator

\d&

10 OHMHE, NACA KM No. L7F2.6

Lateral Stability and Control

The separate effects of the modifications made to the EM-1 glider on C, , C_ , and Cy are shown in figures 8, 9, and 10. 'These

values of Cj , 0*, , and Cv were obtained from the variation

of C2, Cn, and 0y with- ijr> at small angles of yaw (t = ±5°), which is shown in figures 16 to 21.

Dihedral effect.- The value of C, for glider configuration 3,

(original glider with vertical fin removed) increases from 0 at zero lift to 0.0019 at C^ of 0.5; and as CL increases above 0.5, C'j decreases, reaching 0 at C^ of 0.68 and -0.002 at CL of 0.9•

Sealing the elevon control-balance slots (configuration k) did not change the dihedral effect of the wing. The semispan sharp leading edges of configuration 5 increased the dihedral effect of the glider. The maximum value of C^ for this configuration was 0.0024 (which

value in terms of a conventional unswept wing of aspect ratio 6 corresponds to 12° effective dihedral), and the dihedral effect was positive for lift coefficients up to 1.6. This increase in dihedral effect is probably due to the vortex action induced by the semispan sharp leading edges, which delay the stall of the leading wing tip. The addition of the redesigned vertical fin to glider configuration 5 had no appreciable effect on C7 . The

effective dihedral of glider configuration 6 was considerably reduced by the replacement of the semispan sharp leading edges by the faired sharp leading edges of configuration 7, probably because of the increased angle of sweepbaek. The maximum value of Cj. for configuration 7 was O.OOlS-, which decreased to 0 at a

lift coefficient of 0.7, and to -O.OO30 at a lift coefficient of 1.15. The P-80 canopy of configuration 8 did not affect C7

appreciably at lift coefficients below 0-9« At lift coefficients above 0.9, however, the canopy contributed a destabilizing incre- ment to C-> , which decreased the minimum value of Cj. to -0.005

at a lift coefficient of I.I5.

Directional stability.- The- original IM-1 glider wing (configu- ' ration 3) had a small degree of directional stability at lift coefficients between 0.3 and 0.7. The minimum value of C„ for

°t configuraticn 3 was -O.OOO7 at CL of 0-55, and at lift coefficients

KACA EM No. L7F16 ^WMÜ^BBi 11

above -tails value C^ increased with lift coefficient to unstable

values at lift coefficients above 0.7- The sealing of the elevon control-balance slots had no effect on the minimum value of C«^,

hut the lift coefficient at which the directional stability of configuration h became neutral was increased to 0.8l. The semispan sharp leading edges of configuration 5 also extended the lift- coefficient range over which the directional stability was positive' (Cn. «0 at CT = 1>05^ although the minimum value of Cn.

remained at -O.OOO7.

The directional stabil!ty provided by "the redesigned thin vertical surfaces is shown by the comparison of Cn for glider

configurations 5 and 6 in figure 9. The vertical surfaces of con-, figuration 6 contributed a stable increment of approximately -0.002l£ to CJJ. throughout the lift-coefficient range investigated'.'

Cn for configuration 6 was -0.002U- at Cj, of 0.3, -0.0031*- at

C^ of 0.8, and -0.0012 at Cj, of 1.1. These values of Cn are

believed to be adequate for satisfactory flying qualities.

The directional stability of glider configuration 6 was reduced at lift coefficients above 0.7 by the faired sharp leading.edges of configuration 7» The value of Cn. for configuration 7 was -0.0002

at CL of 1.1, and 0 at Cj, Of 1.2. The P-80 canopy of configu-

ration 8 had a destabilizing effect on Cn. which increased with CL,

reducing the directional stability to neutral at Cx, of 1.0.

. Lateral-force effect.- Glider configurations 3 and h had zero lateral-force effect at lift coefficients up to 0.5, ahove which Cy.

increased almost linearly with C^ to 0.008 at C^ of O.85. The

lateral-force effect of configuration 5 increased from 0 at lift coefficients below'«0.8 to 0.005 at CL of 1.1. The lateral-force characteristics of the three glider configurations which had the redesigned thin vertical surfaces attached (configurations 6, 7f and 8) had the same lateral-force characteristics. The values of Cy for these configurations were approximately 0.007 at'a

lift coefficient of 0.3 and increased slightly with lift coefficient, to approximately O.OO8 at a lift coefficient of 1.1.

12 ^HMOBMRi MCA RM No. L7F16

SUMMARY OF RESULTS

The results of tests of eight configurations of the EM-1 glider in the Langley full-scale tunnel are eummarized as follows:

1. The maximum lift coefficient of the EM-1 glider was increased from 0.6l to 1.01 by the installation^ semispan sharp leading edges. Removing the vertical, fin from the glider- and sealing the" elevon control-balance slots increased the maximum lift coefficient to 1.2k. The highest maximum lift coefficient (l«32) was obtained when faired sharp leading edges and thin vertical surfaces were installed on the glider.

2. The maximum lift coefficient of .the original EM-1 glider with vertical fin removed was not critically dependent on yaw angle. As the maximum lift coefficient was increased, however,'by sealing of the elevon control-balance slots and by installation of sharp leading edges, systematic decreases in the maximum lift coeffi- cient resulted from yaw.

3. The original ,DM-1 glider was longitudinally stable for the assumed center-of-gravity position. The semispan sharp leading edges shifted the neutral point forward approximately 3 percent of the root chord at moderate lift coefficients, and the glider configu- ration with these sharp leading edges attached was longitudl.nal.ly unstable, for the assumed center-of-gravity location, at lift coefficients above 0.73« Sealing the elevon control-balance slots and installing faired sharp leading edges, thin vertical surfaces, and the canopy shifted the neutral point forward approximately 8 percent of the root chord in the lift-coefficient range investigated.

k. The dihedral effect of the original EM-1 glider with vertical fin removed was positive at lift coefficients up to 0.7« The semi- span sharp leading edges extended the lift-coeffldent range for positive dihedral effect up to a lift coefficient of 1.0. The faired sharp leading edges decreased the highest lift coefficient for positive dihedral effect to 0 7. The redesigned vertical surfaces did not change, the dihedral effect of the glider.

5. The configurations of the EM-1 glider with no vertical- fin had a small degree of directional stability at low lift coeffi- cients and became directionally unstable at the higher lift coeffi- cients. The redesigned thin vertical surfaces installed on the EM-1 wing having elevon control-balance slot's sealed and semispan

NACA EM No. L7F16

Ik •WBBHBiK NACA EM No, L7F16

TABLE I

DIMENSIONS OF DM-1 GLIDES

Original Glider Wing:

Span, ft. 19.6 Area, sg ft 215.0 Aspect ratio 1.8 Airfoil section Approximately NACA 0015~6^ Thickness, percent chord 15 Point of greatest thickness, percent chord kO Root chord, ft 20.75 Mean geometric chord, ft 10.97 Twist, deg 0 Dihedral, deg 0 Sweepfcack (L.E.), deg 60 Sweepforward (T.E.), deg 15 Vertical location of center of gravity, percent root

chord from chord line ....... 0 Horizontal location of center of gravity, percent root chord . 50

Horizontal control surfaces:' Total elevon area, sq ft 23.3 Elevon chord, ft • . 1.95 Elevon hinge location, percent chord 27 Elevator-angle range, deg ............. i •. 28 to -2k Aileron-angle range, deg '. 21 to -21 Total trim-flap area,'sq ft 6.97 Trim-flap chord, ft I.38

Vertical tail: Height, ft 8.58 Area (to chord line of wing), sq ft . 89*6 Aspect ratio ........ ...... 0.82 Airfoil section Approximately KACA 0015-6k ThickneBS, percent chord . 17*5 Point of greatest thickness, percent chord ^0 Root chord, ft . 19-7 Angle of sweepback (L .E.), deg 65 Angle of sweepforward (T.E.), deg 0 Rudder area, sq ft 8.01 Rudder chord, ft I.32 Hinge location, percent chord ...... 27 Rudder-angle range, deg .....' £23

NATIONAL ADVISORY CC1MMITTEE FOR AERONAUTICS

NACA EM No. L7F16 *•••••••» 15

TABLE I - Concluded

DIMENSIONS OF DM-1 GLIDER - Concluded

Modifications Semispan sharp leading edges:

Length, ft 10.83 Width, in. . . . 3 Thickness, in. ...... O.06 Area, sq ft « 5.U2

Vertical fin: Height, ft 6.85 Area (to chord line), sq ft 33-3 Aspect ratio l.kl Thickness, in..».. ............ O.75 Root chord, ft 9.79 Angle of sveephack {L.E.), deg 35 Angle of sveepforward (T.E.), deg 0

Ventral fin: Height, ft I.56 Area (to wing profile), sq ft 6.22 Thickness, in. O.75

Faired sharp leading edge: Length, ft 16.3 Total projected area, sq ft l6.9

NATIONAL ADVISORY COMMITTEE FOE AERONAUTICS

NACA RM No. L7F16 Fig. 1

W/nd direction

X

w,nd direction

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

Figure /.-The stability system of axes. Arrows indicate posihse directions of moments, forces, and coniroh surface deflections. This system of axes is defined as an orthogonal system having their ongjn at the center of gravity and in which the Z.- axis 12 /n the plane of symmetry and perpendicular fo the relative Mna, the X- axu is m the plane of' symmetry and perpendicular to the Z'-am, and tlte Y-axis is perpendicular TO the plane of symmetry.

cq *

(«) Jrlnolpal dlH«n«lan« of glA4«r oonflguntton 1 {orlftlnel HH-I gllÄrJ.

(b) Mtunilont of th* iralfpaa iMtrp leading ads»» «ad of the eltrcm eantnl-bUMiat clot«.

WmwU. UVI90RY CMMTTU Rt MAMVTIC5

(o) fcrtnolj»!

W-l eU.*"« «1th aoalipan sharp leading

edffea attaobed

DJHL glider vlng vital elnrcm ooatrol- balanne plots amled

BH-l glider wing with eleron control-balanoe slots Real ed., ana aoal- spon sharp leading edgei und redesigned' vortioal

HUTracea attached

DX-1 glider «lag »itb citron oantrol-telenoe slots aealed, faired sharp loading edge», redesigned Yertloal aurfaoea,

and canopy attached g jo

«

en

Original DK-1 glider Original DK-1 glider «log

DH-1 glider vlng Kith alsron oontrol-'balanoe. dots aealed, and aeact- epan sharp leadiflg edges attached

DH-l glider wing witti eleven (jOEtrol-Mlajioe elote »ealed, and fslwd sharp leading edgea and redsalgned Tftrtloal

enxfaoea attached

DX-1 glider oonflgnratlon

figure 4 .- Buutr? of the effeots of Hie modifications nade to tbe DK-1 glider on the Mxlaua lift ooelTlOlmt.

*1 I-" oq

a «

I it) ft

H

«

h o

•p at >

-/6

-72

-fl

-4

0

Glider configuration 1 Glider configuration 2 Glider configuration 8 with

elevon control slots open

0 .4 .6 £ Lift coefficient, G^

1.0 12

NATIONAL ADVISORY COMMITTEE FW AERONAUTICS

Figure 5.- Variation of elevator deflection for trim (C^ = 0) with lift

coefficient for DM-1 glider configurations 1, 2, and 8.

en

Q >

§

a

1 »

•D

Ö o

0 o

01 Ö

•H 60

•H tn O

•P fi U

ft

C o

«H •P « o

-p c!

•H o a i

M OJ

3

— Glider configuration 1 —Glider configuration 2 — Glider configuration 8 with

eleven control slots open

-a

-.006

-.004

-.002

0

> ,^- \ "V^ >v ">

"""~ "• •»*

i

i 1

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

i ! 1 i 1 ! ! \ 0 10 ao 30 40 Q

Angle of attack, Q?, degrees

Figure 7 .- Variation of elevator effectiveness with angle of attack for

DM-1 gliaer configurations 1, 2 , and S.

IT«

NAGA RM No. L7F16 Fig. 8

^

a cd

o a> H 60 C to

C cu

•H •o •rt

1-1

o o

a cu S

§ I 60 C

s

to (3 cd o

O a> cd

PC

o

O

-004-

^r-"——»A

J0& >x ^sy \\

\\ ^^"^ V «! \\

—-GBJ

\ \

— &11 V

o 4 £

Glider configuration 3

Glider configuration H-

Glider configuration 6

Glider configuration 5

-N \

\

V ydl \ -\

Lift coefficient, 0.

Glider configuration 7

"v Glider configuration S

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

Figure 8 •- Effect of the modifications made to the DM-1 glider on the lateral-stability parameter C llf- •

Fig. 9 NACA RM No. L7F16

^

.004

O

Glider configuration 3

> J>>

«4 O

-004 § a .004 •H *

4» C »

•H O

O 4H »

4-1 O

a> to S O 3

NACA RM No. L7F16 Fig. 10

^

&

o

•ä c cd

'S!

c cu

»H o

•H CH 4-i 4' o o

cu o

o

£ CD

c c-f

4-1 O

a; &>i c a

4-1 O a>

+>

.01

o

/^-Glider configuration !j-

Gllder configuration 3

O/

O

Glider configuration 6 ^

Glider configuration 5

.0/

o

Glider configuration 7

Glider configuration S

O .4- .6 /.2

Lift coefficient, CL

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

Figure /(?.- Effect of the modifications made to the Dfc-1 glider on the lateral-force Darameter CY7A, • r

00

8 a

3

u 1 1 I 1 PJ^M*-^ -B-e- inn Q

-.04 1 '. 1 l 1 •

-.08 '

.8 1

1 1

'

.6 1

WiA ' b Afc-

/

^-* nr

f 4 4»

/ - ( » y f •

/ r

E H O

0 o

/ .

/ i

1 l i 1 •

i IAT10NAL AD

( 5 / 0 , a 0 i3 0 ( ) r£ -^ % 0 -.04 -0

J»

Angle of »tt*ok, CC , degrees Longitudinal-foroe «»efficient, C^ (a) Gri.iO.er configuration 1; ^/sO1",

figure// ,- Aerodynamic ohomoterlitloi of the M-l glider vltb control! neutnd

Pltehlng-aoBent coefficient, Os

Q >

3 o

OS

a

o o

9 a i

0

-04

g

/.0

.0

.(9

w111-«;

0 J. 7

s •v. s is

A

7 /

f

^^

4 f- I

*w

*n"

0 10 £0 30 40 0

. NATIONAL ADVISORY COMMITTEE H» «OKKUiTICS

-z -4- -.6 Angle of attack, C)T , degrees

0 -.04 -.06 IionEltadlnal-fOFoe ooeffioient, 0 PltohlnB-W"«!* aoefflolont, 0m

Figur«// .-Continued. 0*.

si-

>

3 5 CO

era

s

C*3

e o

I, B

•H

•s

0

-.04

.08

-II

14-

IZ

10

.6

Longltudln«l-foroe oosfflolent, 0%

3 4 s

a 2

0

P-CH Sr„ 1

Ö 1

-.2 -4- 1

-6 M X \

I

\ Jftf

\ Sfi -

fr ̂ fa y&» \ ]ifcO

- | y 7o r » e ̂

B po ,/

«r

P JB

-43 -S3

/ 0 o - h / » - A - /

- /S9/'

NATIONAL ADVISOR «MITTEE FM HMUU

r

11

cc TIC5

1 i

i

0 10 20 30 40

Angle of »tt»

» .

+> d 0 1.4

8 _

5

04

-.06

-JE

s

g

Longitudinal-farce coefficient! OL.

0 10 10 30 40

Angl« of attaok.CC , toerese

yigujti// .- Continued.

0 -.04 -OS -iZ- -16 Pltohlng-Bonent ooemolent,a

Id) üiLier oonfij.urstion 4.

o >

•

-3 •*l \~* OS

3 04 14

o D

e n

a

0 IZ

-.04 10

0

Loneltudlaal-foroe ooeffiolcnt, 0,

0 -.2 -4 -.6 -ß -/.0 fl>

1 1 1 1 " r

I 1

ife-B-vt Yfd Li eg;) 3

j

fc n

0~3 v^ ¥=d ^

—143 /

•

"•i iJ V*u *w>< Mas

/

/

^

/ '

NATIONAL ADVKOA1 f

1 COMMITTK K» AMÜWUTICS 1 < •

A ' i i 1 i i i • 4

0 10 20 30 40 Angle of attwi, G£ , aegroe«

.04 0 -04

Pitahliig-MjBent coefficient, C

[«) Gilter connjuraUan 6.

o

s *

cu

Jlcjjr»//.- Oor.Ur.ueJ.

c

a .04

Ö

laneitudlnal-faro» oosfflolent, 0Y

Aople of attack,CC, «agrees

.04 0 -OC Fltohlrig-nODeot ooefnoient,

>

•

CB

°a

(f) üli.-.ei e.r:flf-p»tlin 6. 4

J-S.-rc/; .- C:r.;:r.MC,

s O •rl

a 8 o

a

3

0

-04

.06

-II

Longitudinal- force ooefflolent, 0^

/O eO 30 40

Angle of attaofc, QQ , fogren»

0 -04 -08 -72 Pltofalng-moMMit ooafflol«nt,0

(g) Glider configuration 7,

>

f

01

a L c

G 14

04 1.1

ns ID

-/2 .8

J

i 6 •ri O

8 4 3

0

LoBgltndlnal-roroe ooettloient, 0^

0 fO £0 30 40 Angle of «tank, Qc > iogree«

0 -04 -06 -it Pltahlne-mo«t; awfflalent, fl^

3 > o > to

o

3 OS

TO (h) GlUei- eonflfuraUon a.

Figur«» // .- ConolwUd.

Fig. 12 NACA RM No. L7F16

/. / i i i _

1.0 oJfcfca.

A

a =6 Nä

.3 / ° A

.8 A r

/

/

7 A /

.6

5

/ V,mph f? . © 29 3.0*10 H 36 3.7 & 40 4.6 Ä 52 5.3

4 /

/ *

.3 /

/

2 / /*

•

K .1 / NATtC* WITTEE

AL AD FM AE

/ISOBY MNAUT

/

/ CO KS

,.*/! / c< 3NFIC ENT AL

0 8 l£ 16 20 24 28 32

Angle of attaok.CC , degrees

Figure /2 .- Effeot of tunnel airspeed on lift ooefflolent for the DH-1 gilder. Configuration 2.

NACA RM No. L7F16 Fig. 13

Locglt adinaX-fo r<

o -./ 3« ooaffiolent,

J T~ '

Elf.vafar - dpflschon nnofe. 6*.. den

.6 u V of 6 23 / v X

^

~^s

J *.-!£ 7/ Vi '

/. / ifeg) 23 23 O

—; =^ 5

-t*SL 7M//I 7/ V // ( H- i // ^€P^ / // 7/ 7 A / N y

.2 1 O t In // 7 // I / ,

Fig. 14 NACA RM No. L7F16

,rO —.

Longitudinal

f -2

-fore« oo«ffioltnt,

-.3 -A -.5 -.$ i.e. 1 1 i

6g& (beet)

1.0 23

-Ü3

.6 ^ 1> >

^ -- ***>

y f £ / sir .6 A 's y > /, /

/ /• V y, yy

/

4 A v ^ y 1 / y

y

2 // i

0 /

0 a 12 16 20 Angle of fttUok, CC , ft»gre»«

(a) Tarlatlon mth (^ of 0^ and CC .

£4 20 32 36

1.2.

1.0

|

? 6

Se 4 t / 23 j ,-tf?^ o < \ y 6

)

-l&l ' / /

' -?

-e ! K\\ \ x \S \ ll / / / \ \\ \

/ 'L I i f 1 '/ / 1 /

•?,s,, 1 // / i M ' / 1 / / / / / / i 1 / / ' i / 1 V \

/// 1 / / i / / / /

"

/ / / 'W J • / /

.04 O -.04 -OS -.12 Ü8 EL «T* tor hlnge-aoeiivfc ooafflolent, OQ

(b) VcrJetisn *i th C^ of cm and 'J^

/>? O -04 -06 PltohlAff-MOKent coefficient, 0

NATIONU. ADVISORY COHtOTTH F« AUWUITKS

-JZ

i-isiir* A*.- iffsct of eievktor dofleotlon on the aoratynaal^ onaracterUtios of tue 3H-Ä plidtr.

( ? , IiongUuainiil-faroe oorfflolent

f -Z -.3 -.< i -i "

, 1

% < rfcq) II 0

Ä. SA ir\ ^ --//- // • A t.u ,47 il \^ \\\

a // r / v \\\ \ .0 0

jt V 'S _z ^ /y \ Ml 1 ft a. 0 /? X ̂

X , I /

- ̂ ^ III / O

,

I-1 ca

0 6 12. 16 ZO 2.4 26 Angle of attack, CTi *•£"«•

0 -04 -06 pltohJLng-Moaont coefficient, 0B

Figure/5.- Effect of ttlu-flBp daflsotton on tho Mrodjnando oharaoterietlOB of

tin DM-1 glider. OcmfiRuratlon Sj ^n 0°. Ü en

~2A -ao -16 -lZ -8 -4 O ton« or jn.Y, aeerwi

t«) 0,, (^ (j.

3 -£>4

! K -08

-.5

0

, ^Cf-cfL z 0 tea

->r- t— —*-

)— . A- L/4

i

k * -1 L f *•

- O-J i33J

^ i .-*! 0

1 .29'

'3« „

'/m •

k—^_ —k-

U-... ,—*- •ar- ./AS , -as

1 0

-20 -16 -/E -8 -4 0

1» of m,1f. »no» of nw,y, dtgrttf HWtww. Mvseur

I-* TO »

Co

Flenn 'ti .- tffiot gf m M at *wod]MBlr c9t>T*VUrlrtlu of Oil W-l fllijrr. 0onri«v»tlM 3 [ 6," <

Q >

3 o

IT«

i—»•

cu

-u -16 -12. -a -4 isci* of m Y , aatfc

(») °Y. ^,. «!•

JO"?

S 0 71

fc ! * -04- 1

-.00

-Jt

-5

t

5 -£

3

-^o -/

«.. "X-

Q^rtfJ

-llfi.

.ass.

•+--* 219

/ÄJ

> Q >

3 o «

IT1

I-» OS

risnv/7.- Cff«ot o( JM on *• »woajinwls oh»n»Mri.«tiiii of «u Din eXWir, Ooidlfuiauoi t I *," c*.

-24 ~dO -16 -/£ -8 Mi^u of »wij ^« ditni

o >

2 p

I-*

of

i

-/

.04

&

fi -02.

f 04

1

a OZ 8 ^ 1 • 0

1 K -GZ

-.04

»~

-••

In»/3.- Otttt trmnila wiWjMudo *««t«rlm.. it Uu BHL slldw. (feaflimttoii Sf S,« 0*. CD

_ m

0 1 f j S3

i !

i

-J : °^r)

1 1 te

-24 -ZO -16 -12. -6 -4 O 4 Angit of ytLv,TfT, iafnti

UJO*.

Wl» FÖH «»(13 MB 47) Lovell, J. C, Wilson, H. A.

DIVISION: Aerodynamics (2) SECTION; 'Sings and Airfoils (6) «OSS REFERENCES. Airplanes, Triangular wings • Stability (OS76O); YJings - Lift (99169) f—f^/l^

AUTHOR(S) AMER. TITLE: Langley full-scale-tunnel investigation of maximum lift and stability cnarac-

FORG'N. TITLE teristics of an airplane having approximately triangular plan form (tt;-l glider)

ORIGINATING AGENCY: National Advisory Committee for Aeronautics, Washington, D. C. TRANSLATION:

COUNTRY

U.S. LANGUAGE |FORG'N.CLAS;

Eng. U. S.CLASS. DATE

Aug'I|7 PAGES ILLUS.

k5 FEATURES

photos, dlagrs, graphs, drwgs ABSTRACT

Glider having an aspect ratio of 1.8 and 60° swept-back leading edge was tested to determine effects that various modifications had on lift and stability. Uaximum lift co- efficient was increased from 0.61 to 1.01 by installation of sendspan sharp leading edges and from 1.01 to 1.2U removal of vertical fin and sealing of elevon control-balance slots. Results also indicated that airplanes with such plan form can be designed to have acceptable stability characteristics in subcritical speed range.

NOTEi Requests for copies of this report must be addressed to: N.A.C.A., Washington, D. C.

T-2. HQ„ AIR MATERIEL COMMAND WRIGHT FIELD, OHIO, USAAF Wf-O-31 MAI 47 1

u*oC£. • ~>? * & a~ fcLi»/. (U^ZU^cJ!, A*. S"? # füa^