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At least 73 records · Page 4

Transonic Aerodynamic Characteristics of a Wing-Body Combination having a 52.5 deg Sweptback Wing of Aspect Ratio 3 with Conical Camber and Designed for a Mach Number of the Square Root of 2

An investigation has been made of the effects of conical wing camber and supersonic body indentation on the aerodynamic characteristics of a wing-body configuration at transonic speeds. Wing aspect ratio was 3.0, taper ratio was 0.1, and quarter-chord line sweepback was 52.5 deg with airfoil sections of 0.03 thickness ratio. The tests were conducted in the Langley 16-foot transonic tunnel at various Mach numbers from 0.80 to 1.05 at angles of attack from -4 deg to 14 deg. The cambered-wing configuration achieved higher lift-drag ratios than a similar plane-wing configuration. The camber also reduced the effects of wing-tip flow separation on the aerodynamic characteristics. In general, no stability or trim changes below wing-tip flow separation resulted from the use of camber. The use of supersonic body indentation improved the lift-drag ratios at Mach numbers from 0.96 to 1.05.

Igoe, William B.↗

Effect of Ground Interference on the Aerodynamic Characteristics of a 42 Degrees Sweptback Wing

The effects of ground interference on the aerodynamic characteristics of a 42 degrees sweptback wing have been determined at distances above the ground 0.68 and 0.92 of the mean aerodynamic chord (measured from the 0.25 mean aerodynamic chord). The wing was tested without flaps and with inboard trailing-edge split and outboard leading-edge flaps deflected. The wing had an aspect ratio of 4, a taper ratio of 0.625, and NACA 641-112 airfoil sections perpendicular to the 0.273 chord line. The results are, in general, comparable to those reported for unswept wings. The longitudinal stability at the stall was not materially affected at the ground heights of the present tests.

RESEARCH TECHNIQUE, AERODYNAMICS↗

A method for the design of sweptback wings warped to produce specified flight characteristics at supersonic speeds

One of the problems connected with the sweptback wing is the difficulty of controlling the location of the center of pressure and hence the pitching moment. A method is presented for designing a wing to be self-trimming at a given set of flight conditions. Concurrently, the spanwise distribution of load on the wing is made to be approximately elliptical, in an effort to maintain low wing drag.

Tucker, Warren A↗

Longitudinal Stability Characteristics of a 42 Degree Sweptback Wing and Tail Combination at a Reynolds Number of 6.8 x 10(exp 6)

Results are given of a wind-tunnel investigation at a Reynolds number of 6.8 x 10(exp 6) to determine the static longitudinal stability characteristics of a 42 degree sweptback wing and fuselage combination with a sweptback horizontal tail. Included are the effects of vertical position of fuselage and tail with respect to wing for several combinations of high-lift and staff-control devices. Also included is the effect of a simulated ground.

FLAPS - COMPLETE WINGS↗

Transonic Aerodynamic Loading Characteristics of a Wing-Body-Tail Combination Having a 52.5 deg. Sweptback Wing of Aspect Ratio 3 With Conical Wing Camber and Body Indentation for a Design Mach Number of Square Root of 2

An investigation has been made of the effects of conical wing camber and body indentation according to the supersonic area rule on the aerodynamic wing loading characteristics of a wing-body-tail configuration at transonic speeds. The wing aspect ratio was 3, taper ratio was 0.1, and quarter-chord-line sweepback was 52.5 deg. with 3-percent-thick airfoil sections. The tests were conducted in the Langley 16-foot transonic tunnel at Mach numbers from 0.80 to 1.05 and at angles of attack from 0 deg. to 14 deg., with Reynolds numbers based on mean aerodynamic chord varying from 7 x 10(exp 6) to 8 x 10(exp 6). Conical camber delayed wing-tip stall and reduced the severity of the accompanying longitudinal instability but did not appreciably affect the spanwise load distribution at angles of attack below tip stall. Body indentation reduced the transonic chordwise center-of-pressure travel from about 8 percent to 5 percent of the mean aerodynamic chord.

Cassetti, Marlowe D.↗

Transonic Flutter Characteristics of a 45 deg Sweptback Wing with Various Distributions of Ballast Along the Leading Edge

An investigation of the use of ballast at the leading edge of a sweptback wing as a flutter fix has been made. The investigation was conducted in the Langley transonic blowdown tunnel with wing models which had an aspect ratio of 4, sweepback of the quarter-chord line of 450, and a taper ratio of 0.2. Four ballast configurations, which included different amounts of ballast distributed at two different span-wise locations, were investigated. Full-span sting-mounted models were employed. Data were obtained over a Mach number range from 0.65 to 1.32. Comparison of the data for the ballasted wings with data for a similar wing without ballast shows that in the often critical Mach number range between 0.85 and 1.05, the dynamic pressure required for flutter is increased by as much as 100 percent due to the addition of about 6 percent of the wing mass as ballast at the leading edge of the outboard sections. Furthermore, there are indications that similar benefits of leading-edge ballast can be obtained at Mach numbers above M = 1.1. Changing the spanwise location of the ballast and increasing the amount of the ballast by a factor of about 2 had very little additional effect on the dynamic pressure required for flutter. The possibility, therefore, exists that the beneficial effects obtained may be accomplished by using less than the minimum of about 6 percent of the wing mass as ballast as investigated in this paper.

John R Unangst↗

Free-flight Investigation at Transonic and Supersonic Speeds of the Rolling Effectiveness of a 42.7 Degree Sweptback Wing Having Partial-span Ailerons

An investigation of the rolling effectiveness at transonic and supersonic speeds of partial-span ailerons on a 42.7 degree sweptback wing having symmetrical circular-arc airfoil sections of 10-percent thickness ratio normal to the wing quarter-chord line has been made by means of rocket-propelled test vehicles. The results are compared with results of a supersonic wind-tunnel test at Mach number 1.9.

CONTROLS, LATERAL↗

Dynamic Longitudinal and Directional Stability Derivatives for a 45 deg. Sweptback-Wing Airplane Model at Transonic Speeds

An investigation was made at transonic speeds to determine some of the dynamic stability derivatives of a 45 deg. sweptback-wing airplane model. The model was sting mounted and was rigidly forced to perform a single-degree-of-freedom angular oscillation in pitch or yaw of +/- 2 deg. The investigation was made for angles of attack alpha, from -4 deg. to 14 deg. throughout most of the transonic speed range for values of reduced-frequency parameter from 0.015 to 0.040 based on wing mean aerodynamic chord and from 0.04 to 0.14 based on wing span. The results show that reduced frequency had only a small effect on the damping-in-pitch derivative and the oscillatory longitudinal stability derivative for all Mach numbers M and angles of attack with the exception of the values of damping coefficient near M = 1.03 and alpha = 8 deg. to 14 deg. In this region, the damping coefficient changed rapidly with reduced frequency and negative values of damping coefficient were measured at low values of reduced frequency. This abrupt variation of pitch damping with reduced frequency was a characteristic of the complete model or wing-body-vertical-tail combination. The damping-in-pitch derivative varied considerably with alpha and M for the horizontal-tail-on and horizontal-tail-off configurations, and the damping was relatively high at angles of attack corresponding to the onset of pitch-up for both configurations. The damping-in-yaw derivative was generally independent of reduced frequency and M at alpha = -4 deg. to 4 deg. At alpha = 8 deg. to 14 deg., the damping derivative increased with an increase in reduced frequency and alpha for the configurations having the wing, whereas the damping derivative was either independent of or decreased with increase in reduced frequency for the configuration without the wing. The oscillatory directional stability derivative for all configurations generally decreased with an increase in the reduced-frequency parameter, and, in some instances, unstable values were measured for the model configuration with the horizontal tail removed.

Bielat, Ralph P.↗

Effects of Body Shape on the Drag of a 45 degree Sweptback-Wing-Body Configuration at Mach Numbers from 0.90 to 1.43

An investigation was made of the effects of body shape on the drag of a 45 deg sweptback-wing-body combination at Mach numbers from 0.90 to 1.43. Both the expansion and compression fields induced by body indentation were swept back as the stream Mach number increased from 0.94. The line of zero pressure change was generally tangent to the Mach lines associated with the local velocities over the wing and body. The strength of the induced pressure fields over the wing were attenuated with spanwise distance and the major effects were limited to the inboard 60 percent of the wing semispan. Asymmetrical body indentation tended to increase the lift on the forward portion of the wing and reduce the lift on the rearward portion. This redistribution of lift had a favorable effect on the wave drag due to lift. Symmetrical body indentation reduced the drag loading near the wing-body juncture at all Mach numbers. The reduction in drag loading increased in spanwise extent as the Mach number increased and the line of zero induced pressure became more nearly aligned with the line of maximum wing thickness. Calculations of the wave drag due to thickness, the wave drag due to lift, and the vortex drag of the basic and symmetrical M = 1.2 body and wing combinations at an angle of attack of 0 deg predicted the effects of indentation within 11 percent of the wing-basic-body drag throughout the Mach number range from 1.0 to 1.43. Calculations of the wave drag due to thickness, the wave drag due to lift, and the vortex drag for the basic, symmetrical M = 1.2, and asymmetrical M = 1.4 body and wing combinations predicted the total pressure drag to within 8 percent of the experimental value at M = 1.43.

Olstad, Walter B.↗

Longitudinal-stability Investigation of High-lift and Stall-control Devices on a 52 Degree Sweptback Wing with and Without Fuselage and Horizontal Tail at a Reynolds Number of 6.8 x 10(exp 6).

Contains low-speed longitudinal stability characteristics of a 52 degree sweptback wing of aspect ratio 2.88, taper ratio 0.625, and NACA 64 (sub 1)-112 airfoil sections normal to the 0.282-chord line, in combination with split flaps, leading-edge flaps, and upper-surface fences. Low-wing and midwing-fuselage aerodynamic characteristics are presented with and without a horizontal tail at various vertical locations. Tests were conducted at a Reynolds number of 6.8 x 10(exp 6).

STABILITY, LONGITUDINAL - STATIC↗

Effect of Ground Interference on the Aerodynamic and Flow Characteristics of a 42 Degree Sweptback Wing at Reynolds Numbers up to 6.8 x 10(6)

Report presents the results of an investigation of the effects of ground interference on the aerodynamic characteristics of a 42 degree sweptback wing at distances 0.68 and 0.92 of the mean aerodynamic chord from the simulated ground to the 0.25-chord point of the mean aerodynamic chord. Survey data behind the wing, both with and without the simulated ground, are presented in the form of contour charts of downwash, sidewash, and dynamic-pressure ratio at longitudinal stations of 2.0 and 2.8 mean aerodynamic chords behind the wing.

Furlong, G Chester↗

Wind-tunnel investigation of the effects of horizontal-tail position on the low-speed longitudinal stability characteristics of an airplane model with a 35 degrees sweptback wing equipped with chordwise fences

An experimental investigation was made in the Langley stability tunnel to determine whether the low-speed longitudinal stability characteristics of a model with a 35 degree sweptback wing could be improved appreciably by lowering the horizontal tail. The investigation included tests of several components of the model and of various model configurations with chordwise fences on the wing.

Queijo, M J↗

Effect of High-lift Devices on the Low-speed Static Lateral and Yawing Stability Characteristics of an Untapered 45 Degrees Sweptback Wing

Results of a low-speed wind-tunnel investigation to determine the effect of high-lift devices on the static lateral stability derivatives and the yawing derivatives of an untapered 45 degrees sweptback wing are presented. The tests were made in the curved-flow test section of the Langley stability tunnel at a Reynolds number of 1.1 X 10 to the sixth power.

FLAPS, LEADING EDGE - COMPLETE WINGS↗

Wind-tunnel investigation of the effects of steady rolling on the aerodynamic loading characteristics of a 45 degree sweptback wing at high subsonic speeds

An investigation has been conducted in the Langley high- speed 7- by 10-foot tunnel to determine the effect of steady rolling on the aerodynamic loading characteristics of a 45° sweptback wing of aspect ratio 4 in combination with a fuselage. The investigation covered Mach numbers of 0.70, 0.85, and 0.91 at angles of attack up to 13°. The r esults indicate that the loss in damping in roll previously noted for this wing is due to stalling of the tip sections. The effects of rolling velocity on the span load distrib~tion can be satisfactorily estimated if measured pressure-distribution data in pitch are available.

James W Wiggins↗