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Results for “LOW ASPECT RATIO WING”

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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Powered low-aspect-ratio Wing In Ground effect (WIG) aerodynamic characteristics

A wing-in-ground effect configuration was investigated. The configuration used large diameter, low pressure ratio fans mounted about 0.76 wing chord ahead of the wing leading edge to achieve a power augmented ram wing during operation in ground effect. Tests of both in and out of ground effect aerodynamic transition characteristics from very low speeds to cruise speeds are described. The investigation provided a number of conclusions concerning the aerodynamic/propulsive performance interaction. While power augmented lift is required for low speed flight, there is a thrust loss when the efflux is trapped under the wing which reduced the effective thrust to weight available for acceleration by about a third of the installed thrust to weight ratio.

Thomas, J. L.↗
NASA NTRS1951

Low-speed static longitudinal and lateral stability characteristics of two low-aspect-ratio wings cambered and twisted to provide a uniform load at a supersonic flight condition

A delta wing and a tapered sweptback wing of aspect ratios 1.56 and 2.00, respectively, both of which were cambered and twisted so as to provide a uniform load distribution for a supersonic flight condition, were tested in combination with a fuselage at Reynolds numbers between 384,000 and 1,550,000 in order to determine the low-speed lift-drag and static stability characteristics of such wings.

REYNOLDS NUMBER EFFECTS - COMPLETE WINGS↗
NASA NTRS1960

Some Divergence Characteristics of Low-Aspect-Ratio Wings at Transonic and Supersonic Speeds

The problem of chordwise, or camber, divergence at transonic and supersonic speeds is treated with primary emphasis on slender delta wings having a cantilever support at the trailing edge. Experimental and analytical results are presented for four wing models having apex half-angles of 5 deg, 10 deg, 15 deg, and 20 deg. A Mach number range from 0.8 to 7.3 is covered. The analytical results include calculations based on small-aspect-ratio theory, lifting-surface theory, and strip theory. A closed-form solution of the equilibrium equation is given, which is based on low-aspect-ratio theory but which applies only to certain stiffness distributions. Also presented is an iterative procedure for use with other aerodynamic theories and with arbitrary stiffness distribution.

Woolston, Donald S.↗
NASA NTRS1980

Low-aspect-ratio wings

Computer program predicts aerodynamic characteristics of wings having attached flow across part of wing and vortex flow across remainder. Program also uses quasi-vortex lattice method to formulate wing boundary conditions.

Lan, C. E.↗
NASA NTRS1980

A modified T-value method for selection of strain gages for measuring loads on a low aspect ratio wing

A technique which may be useful for selecting strain gages for use in load equations is described. The technique is an adaptation of the previously used T-value method and is applied to a multispar structure. The technique, called the modified T-value method, is used to reduce the number of strain gages used in a load equation from twelve to two. A parallel reduction is made by calculating relative equation accuracies from three applied load distributions. The equations developed from the modified T-value method proved to be accurate more consistently than the T-value method.

Tang, M. H.↗
NASA NTRS1989

Evaluation of a strain-gage load calibration on a low-aspect-ratio wing structure at elevated temperature

The environmental aspect of elevated temperature and its relationship to the science of strain gage calibrations of aircraft structures are addressed. A section of a wing designed for a high-speed aircraft structure was used to study this problem. This structure was instrumented with strain gages calibrated at both elevated and room temperatures. Load equations derived from a high-temperature load calibration were compared with equations derived from an identical load calibration at room temperature. The implications of the high temperature load calibration were studied from the viewpoint of applicability and necessity. Load equations derived from the room temperature load calibration resulted in generally lower equation standard errors than equations derived from the elevated temperature load calibration. A distributed load was applied to the structure at elevated temperature and strain gage outputs were measured. This applied load was then calculated using equations derived from both the room temperature and elevated temperature calibration data. It was found that no significant differences between the two equation systems existed in terms of computing this applied distributed load, as long as the thermal shifts resulting from thermal stresses could be identified. This identification requires a heating of the structure. Therefore, it is concluded that for this structure, a high temperature load calibration is not required. However, a heating of the structure is required to determine thermal shifts.

Reardon, Lawrence F.↗
NASA NTRS1991

Comparison of cryogenic wind tunnel, flight, and computational results for a thin, low-aspect-ratio wing

A research program was conducted at NASA Langley Research Center to build and test a thin, pressure instrumented wing. The wing chosen was the canard of the X-29, which has a maximum thickness of 5 percent of chord. The wing has 90 pressure taps and was built utilizing an advanced laminated metal technique. It was tested in the 0.3-Meter Transonic Cryogenic Tunnel at transonic Mach numbers and over a wide range of Reynolds number. The data are compared with flight data and Navier-Stokes computational results.

Lawing, Pierce L.↗
NASA NTRS1991

Winglet effectiveness on low aspect ratio wings at supersonic Mach numbers

A computational study has been conducted on two wings of aspect ratios 1.244 and 1.865, each having 65-deg leading edge sweep angles, to determine the effects of nonplanar winglets at supersonic Mach numbers. A design Mach number of 1.62 was selected. The winglets studied were parametrically varied in alignment, length, sweep, camber, and thickness to determine the effects of winglet geometry on predicted performance. For the computational analysis, an existing Euler code that employed a marching technique was used. The results indicated that the possibility existed for wing-winglet geometries to equal the performance of wing-alone bodies in supersonic flows with both bodies having the same semispan length. The performance parameters of main interest were the lift-to-pressure drag ratio and the pressure drag coefficient as functions of lift coefficient. The lift coefficient range for this study was from -0.20 to 0.70 with emphasis on the range of 0.10 to 0.22.

Keenan, J. A.↗
NASA NTRS1991

The effects of winglets on low aspect ratio wings at supersonic Mach numbers

A computational study was conducted on two wings, of aspect ratios 1.244 and 1.865, each having 65 degree leading edge sweep angles, to determine the effects of nonplanar winglets at supersonic Mach numbers. A Mach number of 1.62 was selected as the design value. The winglets studied were parametrically varied in alignment, length, sweep, camber, thickness, and dihedral angle to determine which geometry had the best predicted performance. For the computational analysis, an available Euler marching technique was used. The results indicated that the possibility existed for wing-winglet geometries to equal the performance of wing-alone bodies in supersonic flows with both bodies having the same semispan. The first wing with winglet used NACA 1402 airfoils for the base wing and was shown to have lift-to-pressure drag ratios within 0.136 percent to 0.360 percent of the NACA 1402 wing-alone. The other base wing was a natural flow wing which was previously designed specifically for a Mach number of 1.62. The results obtained showed that the natural wing-alone had a slightly higher lift-to-pressure drag than the natural wing with winglets.

Keenan, James A.↗