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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Dual wing, swept forward swept rearward wing, and single wing design optimization for high performance business airplanes

An investigation was performed to compare closely coupled dual wing and swept forward swept rearward wing aircraft to corresponding single wing 'baseline' designs to judge the advantages offered by aircraft designed with multiple wing systems. The optimum multiple wing geometry used on the multiple wing designs was determined in an analytic study which investigated the two- and three-dimensional aerodynamic behavior of a wide range of multiple wing configurations in order to find the wing geometry that created the minimum cruise drag. This analysis used a multi-element inviscid vortex panel program coupled to a momentum integral boundary layer analysis program to account for the aerodynamic coupling between the wings and to provide the two-dimensional aerodynamic data, which was then used as input for a three-dimensional vortex lattice program, which calculated the three-dimensional aerodynamic data. The low drag of the multiple wing configurations is due to a combination of two dimensional drag reductions, tailoring the three dimensional drag for the swept forward swept rearward design, and the structural advantages of the two wings that because of the structural connections permitted higher aspect ratios.

Rhodes, M. D.↗
NASA NTRS1947

Longitudinal Characteristics of a Semispan Model of the Grumman Airplane Design 83 having a Sweptback Wing and of the Model with a Straight Wing as Determined from Wing-Flow Tests at Transonic Speeds, TED No. NACA DE337

An investigation has been made by the NACA wing-flow method to provide information on the relative longitudinal characteristics of a straight and sweptback wing in the transonic speed range. Tests were made of a semispan model of the Grumman airplane design 83 (XFlOF) incorporating a wing swept back 42.5deg with reference to quarter-chord line and also of the model with the swept wing replaced by a straight wing similar to that of the XF9F airplane. The airfoil sections were symmetrical 64l-series, with thickness ratios of 12 percent for the straight wing and 10 percent for the sweptback wing parallel to the stream direction. Measurements were made of normal force, chord force, and pitching moment at various angles of attack with the two wings both with and without the empennage, and with the fuselage alone. The tests covered a range of effective Mach numbers at the wing of the model from 0.65 to 1.10.

Silsby, Norman S.↗
NASA NTRS1972

Effect of wing sweep, angle of attack, Reynolds number, and wing root fillet on the interference heating to the wing windward surface of an entry vehicle configuration

The phase-change-coating technique was used to study the interference heating to the windward surface of 14 deg, 25 deg, and 50 deg swept wings of an entry vehicle configuration. One wing root of each model was faired to the fuselage with a fillet. Tests were made at Mach 8 at angles of attack of 0 deg, 20 deg, 40 deg, and 60 deg and at free-stream Reynolds numbers based on model length of 0.47 and 1.7 million. Bow shock impingement heating was found to increase in magnitude and affected area with increasing angle of attack until at a higher angle of attack it decreases; this angle of attack is lower for a 50 deg swept wing. Wing root interference heating was found to increase with angle of attack up to 40 deg and then to remain approximately constant. Consequently, wing root interference heating becomes the major type of interference heating at large angles of attack, and this occurs at a lower angle of attack for the highest sweep angle. A wing leading-edge root fillet reduces the peak in wing root interference heating near the leading edge, and increasing Reynolds number increases the level of interference heating.

Clark, L. E.↗
NASA NTRS1985

Aerodynamic-structural study of canard wing, dual wing, and conventional wing systems for general aviation applications

An analytical aerodynamic-structural airplane configuration study was conducted to assess performance gains achievable through advanced design concepts. The mission specification was for 350 mph, range of 1500 st. mi., at altitudes between 30,000 and 40,000 ft. Two payload classes were studied - 1200 lb (6 passengers) and 2400 lb (12 passengers). The configurations analyzed included canard wings, closely coupled dual wings, swept forward - swept rearward wings, joined wings, and conventional wing tail arrangements. The results illustrate substantial performance gains possible with the dual wing configuration. These gains result from weight savings due to predicted structural efficiencies. The need for further studies of structural efficiencies for the various advanced configurations was highlighted.

Selberg, B. P.↗
NASA NTRS1938

A Flight Comparison of Conventional Ailerons on a Rectangular Wing and of Conventional and Floating Wing-Tip Ailerons on a Tapered Wing

Report presents the results of flight tests comparing the relative effectiveness of conventional ailerons of the same size on wings of rectangular and tapered plan forms made with a Fairchild 22 airplane. Information is included comparing conventional and floating wing-tip ailerons on a tapered wing. The results showed that the conventional ailerons were somewhat more effective on the tapered than on the rectangular wing. The difference, however, was so small as to be imperceptible to the pilots. The floating wing-tip ailerons were only half as effective as the conventional ailerons and, for this reason, were considered unsatisfactory.

Soule, H A↗
NASA NTRS1961

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.↗
NASA NTRS1961

Low-Speed Investigation of the Effects of Frequency and Amplitude of Oscillation in Sideslip on the Lateral Stability Derivatives of a 60 deg Delta Wing, a 45 deg Sweptback Wing and an Unswept Wing

A low-speed investigation has been conducted in the Langley stability tunnel to study the effects of frequency and amplitude of sideslipping motion on the lateral stability derivatives of a 60 deg. delta wing, a 45 deg. sweptback wing, and an unswept wing. The investigation was made for values of the reduced-frequency parameter of 0.066 and 0.218 and for a range of amplitudes from +/- 2 to +/- 6 deg. The results of the investigation indicated that increasing the frequency of the oscillation generally produced an appreciable change in magnitude of the lateral oscillatory stability derivatives in the higher angle-of-attack range. This effect was greatest for the 60 deg. delta wing and smallest for the unswept wing and generally resulted in a more linear variation of these derivatives with angle of attack. For the relatively high frequency at which the amplitude was varied, there appeared to be little effect on the measured derivatives as a result of the change in amplitude of the oscillation.

Lichtenstein, Jacob H.↗
NASA NTRS1952

Theoretical damping in roll and rolling moment due to differential wing incidence for slender cruciform wings and wing-body combinations

A method of analysis based on slender-wing theory is developed to investigate the characteristics in roll of slender cruciform wings and wing-body combinations. The method makes use of the conformal mapping processes of classical hydrodynamics which transform the region outside a circle and the region outside an arbitrary arrangement of line segments intersecting at the origin. The method of analysis may be utilized to solve other slender cruciform wing-body problems involving arbitrarily assigned boundary conditions. (author)

Adams, Gaynor J↗
NASA NTRS1949

Investigation of a Thin Straight Wing of Aspect Ratio 4 by the NACA Wing-flow Method : Lift and Pitching-moment Characteristics of the Wing Alone

This report presents measurements of the lift and pitching-moment characteristics of a straight wing of aspect ratio 4, taper ratio 0.5, having a symmetrical double-wedge airfoil section with a maximum thickness of 4.4-percent chord. The tests were conducted in the Mach number range 0.51 to 1.20, Reynolds numbers 380,000 to 660,000, by the NACA wing-flow method. The results are compared with theory and with wind-tunnel tests of a similar model. It is indicated that in the Mach number range 0.82 to 1.00 the model surface, profile, and test Reynolds number all would be very important considerations in any attempt to study or predict full-scale characteristics from small-model tests.

MACH NUMBER EFFECTS - COMPLETE WINGS↗
NASA NTRS1977

A comparison of the experimental aerodynamic characteristics of an oblique wing with those of a swept wing

Force and moment characteristics were measured for two trapezoidal oblique wings and a conventional swept wing mounted on a body of revolution at Mach numbers from 0.25 to 2.0. Both oblique wings had the same planform, but differed in profile and flexibility. One of the oblique wings was made of solid steel and had a maximum thickness-to-chord ratio of 4 percent. The other wing was built up by taking an aluminum wing and adding epoxy material to the upper surface to increase the maximum thickness-to-chord ratio to 8.2 percent. The aspect ratio for both oblique wings when swept 45 deg, and for the swept wing with 45 deg of sweep, was 4.1. Data were obtained at unit Reynolds numbers ranging from 3.3 to 8.2 million per meter and were compared with previously obtained data on the aluminum wing before it was built up with epoxy. Wing flexibility designed into the aluminum and built-up aluminum oblique wings increased the range of lift coefficients from 0.30 to 0.70 over which the pitching-moment curves were linear. However, flexibility did not improve the linearity of the rolling-moment curves and produced sizable side forces. At a Mach number of 0.95, the trapezoidal oblique wing had little or no improvement in the lift/drag ratios over those for a conventional swept wing of the same aspect ratio, sweep, and profile.

Hopkins, E. J.↗
NASA NTRS1993

Experimental effects of wing location on wing-body pressures at supersonic speeds

An experimental study was performed at supersonic speeds to measure wing and body spanwise pressure distributions on an axisymmetric-body delta wing model on which the wing vertical location on the body was systematically varied from low- to high-mounted positions. In addition, for two of these positions both horizontal and radial wing angular orientations relative to the body were tested, and roll angle effects were investigated for one of the positions. Seven different wing-body configurations and a body-alone configuration were studied. The test was conducted at Mach numbers from 1.70 to 2.86 at angles of attack from about -4 deg to 24 deg. Pressure orifices were located at three longitudinal stations on each wing-body model, and at each station the orifices were located completely around the body, along the lower surface of the right wing (looking upstream), and along the upper surface of the left wing. All pressure coefficient data are tabulated and selected samples are shown graphically to illustrate the effects of the test variables. The effects of angle of attack, roll angle, Mach number, longitudinal station, wing vertical location, wing angular orientation, and wing-body juncture are analyzed. The vertical location of the wing on the body had a very strong effect on the body pressures. For a given angle of attack at a roll angle of 0 deg, the pressures were virtually constant in the spanwise direction across the windward surfaces of the wing-body combination. Pressure-relieving, channeling, and vortex effects were noted in the data.

Allen, Jerry M.↗
NASA NTRS2000

Flexible Wing Model for Structural Sizing and Multidisciplinary Design Optimization of a Strut-Braced Wing

This paper describes a structural and aeroelastic model for wing sizing and weight calculation of a strut-braced wing. The wing weight is calculated using a newly developed structural weight analysis module considering the special nature of strut-braced wings. A specially developed aeroelastic model enables one to consider wing flexibility and spanload redistribution during in-flight maneuvers. The structural model uses a hexagonal wing-box featuring skin panels, stringers, and spar caps, whereas the aerodynamics part employs a linearized transonic vortex lattice method. Thus, the wing weight may be calculated from the rigid or flexible wing spanload. The calculations reveal the significant influence of the strut on the bending material weight of the wing. The use of a strut enables one to design a wing with thin airfoils without weight penalty. The strut also influences wing spanload and deformations. Weight savings are not only possible by calculation and iterative resizing of the wing structure according to the actual design loads. Moreover, as an advantage over the cantilever wing, employment of the strut twist moment for further load alleviation leads to increased savings in structural weight.

Gern, Frank H.↗
NASA NTRS1994

Numerical study of the trailing vortex of a wing with wing-tip blowing

Trailing vortices generated by lifting surfaces such as helicopter rotor blades, ship propellers, fixed wings, and canard control surfaces are known to be the source of noise, vibration, cavitation, degradation of performance, and other hazardous problems. Controlling these vortices is, therefore, of practical interest. The formation and behavior of the trailing vortices are studied in the present research. In addition, wing-tip blowing concepts employing axial blowing and spanwise blowing are studied to determine their effectiveness in controlling these vortices and their effects on the performance of the wing. The 3D, unsteady, thin-layer compressible Navier-Stokes equations are solved using a time-accurate, implicit, finite difference scheme that employs LU-ADI factorization. The wing-tip blowing is simulated using the actuator plane concept, thereby, not requiring resolution of the jet slot geometry. Furthermore, the solution blanking feature of the chimera scheme is used to simplify the parametric study procedure for the wing-tip blowing. Computed results are shown to compare favorably with experimental measurements. It is found that axial wing-tip blowing, although delaying the rolling-up of the trailing vortices and the near-field behavior of the flowfield, does not dissipate the circulation strength of the trailing vortex farther downstream. Spanwise wing-tip blowing has the effect of displacing the trailing vortices outboard and upward. The increased 'wing-span' due to the spanwise wing-tip blowing has the effect of lift augmentation on the wing and the strengthening of the trailing vortices. Secondary trailing vortices are created at high spanwise wing-tip blowing intensities.

Lim, Hock-Bin↗
NASA NTRS1976

Effect of wing bend on the experimental force and moment characteristics of an oblique wing

Static longitudinal and lateral/directional force and moment characteristics are presented for an elliptical oblique wing mounted on top of a Sears-Haack body of revolution. The wing had an aspect ratio of 6 (based on the unswept span) and was tested at various sweep angles relative to the body axis ranging from 0 to 60 deg. In an attempt to create more symmetrical spanwise wing stalling characteristics, both wing panels were bent upward to produce washout on the trailing wing panel and washing on the leading wing panel. Small fluorescent tufts were attached to the wing surface to indicate the stall progression on the wing. The tests were conducted throughout a Mach number range from 0.6 to 1.4 at a constant unit Reynolds number of 8.2 x 10 per meter. The test results indicate that upward bending of the wing panels had only a small effect on the linearity of the moment curves and would require an impractical wing-pivot location at low lift to eliminate the rolling moment resulting from this bending.

Hopkins, E. J.↗