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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Aerodynamic Characteristics of a Proposed Personnel Launch System (PLS) Lifting-Body Configuration at Mach Numbers from 0.05 to 20.3. Supplement

A wind-tunnel investigation was performed to determine the aerodynamic characteristics of a proposed lifting-body personnel launch system (PLS) configuration over a Mach range of 0.05 to 20.3. The test configuration had a low-aspect-ratio body with a flat undersurface and three fins on the upper aft body. Data are presented with a minimum of analysis. All of the experimental data were placed in a structured data base using the R:BASE system. This is the CD-ROM that is available for this report.

Cruz, Christopher I.↗
NASA NTRS1972

Aerodynamic static stability characteristics of the MSFC 33-foot pump fed booster at high angles of attack

Experimental aerodynamic investigations were conducted in the 14-inch trisonic wind tunnel during early February 1972 on a 0.00340 scale model of the 33-foot diameter space shuttle pump fed booster configuration. The basic configuration tested was a 40-deg cone/cylinder. Six component aerodynamic force and moment data were recorded over a Mach number range from 0.6 to 5.0, angles-of-attack from 50 to 90 deg at 0 deg sideslip and over a sideslip range from -10 to +10 deg at 60 and 80 deg angles-of-attack. Primary configuration variables were fin area and body cutout size.

Hamilton, T.↗
NASA NTRS1979

Nike Black Brant V high altitude dynamic instability characteristics

Flight experience on the Nike Black Brant V has demonstrated the existence of plume induced flow separation over the fins and aft body of the Black Brant V motor. Modelling of the forces associated with this phenomenon as well as analysis of the resultant vehicle coning motion and its effect on the velocity vector heading are presented. A summary of Nike Black Brant V flight experience with high altitude dynamic instability is included.

Montag, W. H.↗
NASA NTRS1981

Experiments on three-dimensional separating and reattaching flows

In studies of multijet rockets, failure to find solutions when using a reasonable mathematical model led to performing airflow tests of supersonic circular jets exhausting into noncircular channels of various sizes. Amomalous base pressure trends and puzzling wall pressure patterns resulted. A flow-into-the-corner test was then devised, using a 90 deg trough behind a back step. A vortex pair, generated by the unsymmetrical squeezing of the shear layer, was found to fill much of the corner and provided an explanation for the peculiar results of the previous tests. No previous reference could be found to this phenomenon. Further experiments of bodies with base fins defined the conditions for creating this trough vortex effect. The trough vortex was used successfully as an igniter/flameholder for combustion of hydrogen in a supersonic stream. Other applications are suggested for base drag reduction, base burning and for providing guidance to avoid errors in half-plane wind tunnel model testing.

Zumwalt, G. W.↗
NASA NTRS1989

A user's manual for the method of moments Aircraft Modeling Code (AMC)

This report serves as a user's manual for the Aircraft Modeling Code or AMC. AMC is a user-oriented computer code, based on the method of moments (MM), for the analysis of the radiation and/or scattering from geometries consisting of a main body or fuselage shape with attached wings and fins. The shape of the main body is described by defining its cross section at several stations along its length. Wings, fins, rotor blades, and radiating monopoles can then be attached to the main body. Although AMC was specifically designed for aircraft or helicopter shapes, it can also be applied to missiles, ships, submarines, jet inlets, automobiles, spacecraft, etc. The problem geometry and run control parameters are specified via a two character command language input format. The input command language is described and several examples which illustrate typical code inputs and outputs are also included.

Peters, M. E.↗
NASA NTRS1994

A users manual for the method of moments Aircraft Modeling Code (AMC), version 2

This report serves as a user's manual for Version 2 of the 'Aircraft Modeling Code' or AMC. AMC is a user-oriented computer code, based on the method of moments (MM), for the analysis of the radiation and/or scattering from geometries consisting of a main body or fuselage shape with attached wings and fins. The shape of the main body is described by defining its cross section at several stations along its length. Wings, fins, rotor blades, and radiating monopoles can then be attached to the main body. Although AMC was specifically designed for aircraft or helicopter shapes, it can also be applied to missiles, ships, submarines, jet inlets, automobiles, spacecraft, etc. The problem geometry and run control parameters are specified via a two character command language input format. This report describes the input command language and also includes several examples which illustrate typical code inputs and outputs.

Peters, M. E.↗
NASA NTRS1980

Air speed and attitude probe

An air speed and attitude probe characterized by a pivot shaft normally projected from a data boom and supported thereby for rotation about an axis of rotation coincident with the longitudinal axis of the shaft is described. The probe is a tubular body supported for angular displacement about the axis of rotation and has a fin mounted on the body for maintaining one end of the body in facing relation with relative wind and has a pair of transducers mounted in the body for providing intelligence indicative of total pressure and static pressure for use in determining air speed. A stack of potentiometers coupled with the shaft to provide intelligence indicative of aircraft attitude, and circuitry connecting the transducers and potentiometers to suitable telemetry circuits are described.

Baker, G. J.↗
NASA NTRS1953

Wind-tunnel investigation of the effects of various dorsal-fin and vertical-tail configurations on the directional stability of a streamlined body at transonic speeds : transonic-bump method

Yawing-moment coefficients were obtained for several dorsal-fin and vertical-tail configurations in combination with a streamlined body through a large angle-of-sideslip range and a Mach number range of 0.59 to 1.11. The results indicated that dorsal fins improved the directional stability characteristics of the body alone and the body-vertical-tail configuration. A ring tail was more effective at small angles of sideslip and less effective at large angles of sideslip than a tapered low-aspect-ratio vertical tail.

TAIL-BODY COMBINATIONS - MISSILES↗
NASA NTRS1949

Moments of Cambered Round Bodies

Results are presented for the moments and position of force centers of a series of cambered round bodies derived from a torpedo-like body of revolution. The effects of placing fins on the rear of the body of revolution are also included.

AIRPLANES - COMPONENTS IN COMBINATION↗
NASA NTRS1985

Program LRCDM2: Improved aerodynamic prediction program for supersonic canard-tail missiles with axisymmetric bodies

Program LRCDM2 was developed for supersonic missiles with axisymmetric bodies and up to two finned sections. Predicted are pressure distributions and loads acting on a complete configuration including effects of body separated flow vorticity and fin-edge vortices. The computer program is based on supersonic panelling and line singularity methods coupled with vortex tracking theory. Effects of afterbody shed vorticity on the afterbody and tail-fin pressure distributions can be optionally treated by companion program BDYSHD. Preliminary versions of combined shock expansion/linear theory and Newtonian/linear theory have been implemented as optional pressure calculation methods to extend the Mach number and angle-of-attack ranges of applicability into the nonlinear supersonic flow regime. Comparisons between program results and experimental data are given for a triform tail-finned configuration and for a canard controlled configuration with a long afterbody for Mach numbers up to 2.5. Initial tests of the nonlinear/linear theory approaches show good agreement for pressures acting on a rectangular wing and a delta wing with attached shocks for Mach numbers up to 4.6 and angles of attack up to 20 degrees.

Dillenius, Marnix F. E.↗
NASA NTRS1974

An experimental study of the validity of the heat-field concept for sonic-boom alleviation

An experimental program was carried out in the NASA-Langley 4 ft x 4 ft supersonic pressure tunnel to investigate the validity of the heat-field concept for sonic boom alleviation. The concept involves heating the flow about a supersonic aircraft in such a manner as to obtain an increase in effective aircraft length and yield an effective aircraft shape that will result in a shock-free pressure signature on the ground. First, a basic body-of-revolution representing an SST configuration with its lift equivalence in volume was tested to provide a baseline pressure signature. Second, a model having a 5/2-power area distribution which, according to theory, should yield a linear pressure rise with no front shock wave was tested. Third, the concept of providing the 5/2-power area distribution by using an off-axis slender fin below the basic body was investigated. Then a substantial portion (approximately 40 percent) of the solid fin was replaced by a heat field generated by passing heated nitrogen through the rear of the fin.

Swigart, R. J.↗
NASA NTRS1979

Effects of a military cargo pod and tail fins on the aerodynamic characteristics of a large wide-body transport model

Wind tunnel tests were conducted on a 0.03 scale model of a large wide-body commercial aircraft to determine the effects on the static aerodynamic characteristics resulting from the attachment of a belly pod for the long-range deployment of outsize military equipment. The effectiveness of horizontal-tip fins in augmenting directional stability was investigated. At a test Reynolds number of 1.08 x 1,000,000, the addition of the pod results in an increase in total drag of approximately 20 percent. Trim drag due to the pod is very small. Although the pod produces a significant decrease in directional stability, the addition of the tip fins restores some of the stability, particularly at the lower angles of attack.

Jernell, L. S.↗
NASA NTRS1977

Component aerodynamic characteristics of banked cruciform missiles with arbitrary control deflections

A comprehensive computer code has been developed for the prediction of the static aerodynamic characteristics of cruciform wing-body combinations with one or two sets of fins. The code may be used for subsonic, transonic, and supersonic speeds. Arbitrary bank angles and control deflections are allowed. The present version of the code may be used for angles of attack up to 20 deg. The code computes the forces and moments acting on each component of the missile including the effects of vortices shed by the body and fins. Comparisons between experiment and theory indicate good agreement for longitudinal characteristics and fair to good agreement for lateral characteristics.

Hemsch, M. J.↗
NASA NTRS1986

Aerodynamic Prediction for Supersonic Canard-Tail Missiles

LRCDM2 computer program developed to calculate pressure distribution at points on surfaces of complete supersonic missile. Missile comprises up to two finned sections attached to axisymmetric body of circular cross section. Includes effects of vortex shedding due to forebody and forward fins, providing more accurate rolling moments. LRCDM2 written in FORTRAN IV.

Dillenius, M. F.↗
NASA NTRS1976

Trailing anemometer for low airspeed calibration

A propeller-type trailing airspeed anemometer system is described for low airspeed (M not exceeding 0.2) calibration which has improved accuracy and is easy to implement as compared to most methods currently in use. The trailing anemometer system consists of the trailing anemometer itself, a deployment mechanism, and an operator's control box. The trailing anemometer is a small low-drag brass body provided with tail fins for self-alignment with the airstream. The rotational speed of a small six-bladed low-inertia propeller is sensed with a miniature self-generating tachometer inside the anemometer. A very satisfactory airspeed calibration can be made with this device in which true airspeed can be measured to within 1 knot. Results from flight calibration of an aircraft and trail-back characteristics of the anemometer and cable are included. The operating speed range of the designed cable-anemometer combination is 7 to 165 knots.

Fisher, B. D.↗
NASA NTRS1979

The role of wind tunnels in predicting sounding rocket aerodynamics

The aerodynamic characteristics of sounding rockets, in some cases, may be adequately determined by various estimating procedures, however, there are cases where these procedures fail and wind tunnel studies become necessary. The present paper deals with configurations of the latter type, for which the problems of concern include mismatched diameters between stages, mutual fin interference effects, fin alignment and orientation, body deflections between stages, boundary layer growth, and stability changes that occur as stages are dropped. Some characteristics related to separated flow, interference flow fields, and Reynolds number are examined.

Spearman, M. L.↗
NASA NTRS1991

An experimental study of a three-dimensional shock wave/turbulent boundary-layer interaction at a hypersonic Mach number

Experimental data for a series of three-dimensional shock-wave/turbulent-boundary-layer interaction flows at Mach 8.2 are presented. The test bodies, composed of sharp fins fastened to a flat-plate test surface, were designed to generate flows with varying degrees of pressure gradient, boundary-layer separation, and turning angle. The data include surface-pressure, heat-transfer, and skin-friction distributions, as well as limited mean flowfield surveys both in the undisturbed and interaction regimes. The data were obtained for the purpose of validating computational models of these hypersonic interactions.

Kussoy, M. I.↗