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  • AERODYNAMICS
  • 1970-1974  (1.256)
  • 101
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    Extension of leading-edge-suction analogy to wings with separated flow around the side edges at subsonic speeds (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A method for determining the lift, drag, and pitching moment for wings which have separated flow at the leading and side edges with subsequently reattached flow downstream and inboard is presented. Limiting values of the contribution to lift of the side-edge reattached flow are determined for rectangular wings. The general behavior of this contribution is computed for rectangular, cropped-delta, cropped-diamond, and cropped-arrow wings. Comparisons of the results of the method and experiment indicate reasonably good correlation of the lift, drag, and pitching moment for a wide planform range. The agreement of the method with experiment was as good as, or better than, that obtained by other methods. The procedure is computerized and is available from COSMIC as NASA Langley computer program A0313.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TR-R-428 , L-9460
    Format: application/pdf
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  • 102
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    Wind-tunnel investigation of an externally blown flap STOL transport model including and investigation of wall effects (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A wind-tunnel investigation was conducted in the Langley V/STOL tunnel and in a scaled version of the Ames 40- by 80-foot tunnel test section installed as a liner in the Langley V/STOL tunnel to determine the effect of test-section size on aerodynamic characteristics of the model. The model investigated was a swept-wing, jet-powered, externally blown flap (EBF) STOL transport configuration with a leading-edge slat and triple-slotted flaps. The model was an 0.1645-scale model of a 11.58-meter (38.0-ft) span model designed for tests in a 40- by 80-foot tunnel. The data compare the aerodynamic characteristics of the model with and without the tunnel liner installed. Data are presented as a function of thrust coefficient over an angle-of-attack range of 0 deg to 25 deg. A thrust-coefficient range up to approximately 4.0 was simulated, most ot the tests being conducted at a free-stream dynamic pressure of 814 Newtons/sq m (17 lb sq ft). The data are presented with a minimum of analysis.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3009
    Format: application/pdf
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  • 103
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    Some observations about the components of transonic fan noise from narrow-band spectral analysis (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Qualitative and quantitative spectral analyses are presented that give the broadband-noise, discrete-tone, and multiple-tone properties of the noise generated by a full-scale high-bypass single-stage axial-flow transonic fan (fan B, NASA Quiet Engine Program). The noise components were obtained from narrow-band spectra in conjunction with 1/3-octave-band spectra. Variations in the pressure levels of the noise components with fan speed, forward-quadrant azimuth angle, and frequency are presented and compared. The study shows that much of the apparent broadband noise on 1/3-octave-band plots consists of a complex system of shaft-order tones. The analyses also indicate the difficulties in determining or defining noise components, especially the broadband level under the discrete tones. The sources which may be associated with the noise components are discussed.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7788 , E-7989
    Format: application/pdf
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  • 104
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    Gust alleviation for a STOL transport by using elevator, spoilers, and flaps (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Control laws were developed to investigate methods of alleviating the response of a STOL transport to gusty air. The transport considered in the study had triple-slotted, externally blown jet flaps and a large T-tail. The control devices used were the elevator, spoilers, and flaps. A hybrid computing system was used to simulate linearized longitudinal dynamics of the aircraft and to implement a conjugate gradient optimal search algorithm. The aircraft was simulated in the low-speed approach condition only. Feedback control matrices were found which minimized the average of a quadratic functional involving passenger compartment accelerations, pitch angle and rate, flight path angle and speed variations. The optimization was performed for artificially designed gust inputs in the form of predetermined rectangular waveforms. Results were obtained for elevator, spoilers, and flaps acting singly and in combination. Additional results were obtained for unit sinusoidal gust inputs by using the gain matrices computed for the artificial test gusts. Various sensor configurations were also investigated.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7559 , L-9250
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  • 105
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    Experimental evaluation of compliant surfaces at low speeds (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: An experimental study was devised to determine the profile drag on a subsonic wind tunnel model partially covered with various compliant surface materials. The model consisted of a large section of constant thickness bounded fore and aft by symmetric airfoil fairings. A flat rigid plate, the control surface, could be exchanged for four contiguous complaint panels. The flexible media generally consisted of thin polyvinylchloride membranes stretched to various tensions over trapped fluid cavities of air, water, or polyethelene oxide solution, or over dry or flooded open-celled polyurethane foams. On the basis of very accurate direct-force cell measurements, all configurations were found to yield profile drags equal to or slightly higher than that obtained for the conventional rigid surface case. The results indicate that the potential for practical drag-reducing applications will be limited to either high-density or high-speed flows where more sensible pressure perturbations occur.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3119 , A-5596
    Format: application/pdf
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  • 106
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    Flight Reynolds number effects on a fighter-type, circular-arc-19 deg conic boattail nozzle at subsonic speeds (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A circular-arc - conic boattail nozzle, typical of those used on a twin engine fighter, was tested on an underwing nacelle mounted on an F-106B aircraft. The boattail had a radius ratio r/r sub c of 0.41 and a terminal boattail angle of approximately 19 deg. The gas generator was a J85-GE-13 turbojet engine. The effects of Reynolds number and angle of attack on boattail pressure drag and boattail pressure profiles were investigated. Increasing Reynolds number resulted in reduced boattail drag at both Mach numbers of 0.6 and 0.9.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3121 , E-7997
    Format: application/pdf
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  • 107
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    Aerodynamic performance of a 1.25-pressure-ratio axial-flow fan stage (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Aerodynamic design parameters and overall and blade-element performances of a 1.25-pressure-ratio fan stage are reported. Detailed radial surveys were made over the stable operating flow range at rotative speeds from 70 to 120 percent of design speed. At design speed, the measured stage peak efficiency of 0.872 occurred at a weight flow of 34.92 kilograms per second and a pressure ratio of 1.242. Stage stall margin is about 20 percent based on the peak efficiency and stall conditions. The overall peak efficiency for the rotor was 0.911. The overall stage performance showed no significant change when the stators were positioned at 1, 2, or 4 chords downstream of the rotor.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3083 , E-7800
    Format: application/pdf
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  • 108
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    Theoretical surface velocity distributions on acoustic splitter geometries for an engine inlet (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The potential-flow velocity distributions on several splitter geometries in an engine inlet and their variation with different splitter leading-edge shapes and distances from the inlet highlight were analyzed. The velocity distributions on the inner and outer surfaces of the splitters are presented for low-speed and cruise conditions. At zero incidence angle, the splitter with the 4-to-1 elliptical leading edge had lower peak velocities and velocity gradients than the splitter with the 2-to-1 elliptical leading edge. The velocity gradients decreased as the distance from the inlet highlight to the splitter leading edge was increased. For a given distance, the peak velocity on the splitter inner surface increased with increasing inlet incidence angle. At an incidence angle of 50 deg, the velocity level and gradients on the inner surface of the splitter in the forward position were sufficiently severe to suggest local separation.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3114 , E-8001
    Format: application/pdf
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  • 109
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    Drag reductions obtained by modifying a box-shaped ground vehicle (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A box-shaped ground vehicle was used to simulate the aerodynamic drag of high volume transports, that is, delivery vans, trucks, or motor homes. The coast-down technique was used to define the drag of the original vehicle, having all square corners, and several modifications of the vehicle. Test velocities ranged up to 65 miles per hour, which provided maximum Reynolds numbers of 1 times 10 to the 7th power based on vehicle length. One combination of modifications produced a reduction in aerodynamic drag of 61 percent as compared with the original square-cornered vehicle.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-56027
    Format: application/pdf
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  • 110
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    Prospects for reduced energy transports: A preliminary analysis (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The recent energy crisis and subsequent substantial increase in fuel prices have provided increased incentive to reduce the fuel consumption of civil transport aircraft. At the present time many changes in operational procedures have been introduced to decrease fuel consumption of the existing fleet. In the future, however, it may become desirable or even necessary to introduce new fuel-conservative aircraft designs. This paper reports the results of a preliminary study of new near-term fuel conservative aircraft. A parametric study was made to determine the effects of cruise Mach number and fuel cost on the optimum configuration characteristics and on economic performance. For each design, the wing geometry was optimized to give maximum return on investment at a particular fuel cost. Based on the results of the parametric study, a nominal reduced energy configuration was selected. Compared with existing transport designs, the reduced energy design has a higher aspect ratio wing with lower sweep, and cruises at a lower Mach number. It has about 30% less fuel consumption on a seat-mile basis.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-62383
    Format: application/pdf
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  • 111
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    Development of a computer program to obtain ordinates for NACA-6 and 6A-series airfoils (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A computer program was developed to produce the ordinates for airfoils of any thickness, thickness distribution, or camber in the NACA 6- and 6A-series. For the 6-series and for all but the leading edge of the 6A-series, agreement between the ordinates obtained from the new program and previously published values is generally within .00005 chord. Near the leading edge of the 6A-series airfoils, differences up to .00035 chord are found.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3069 , L-9558
    Format: application/pdf
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  • 112
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    Further analysis of broadband noise measurements for a rotating blade operating with and without its shed wake blown downstream (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: An experimental investigation has been conducted to investigate the broadband noise generated by a rotating-blade system. Tests were made with circular and NACA 0012 rotor-blade sections. The blades were operated only with zero lift at each radial station. Tests were made both with zero axial velocity, so that the blades operated in their own turbulent wake, and with a small axial velocity imposed by the wind tunnel to blow the wake of one blade away before the passage of the next blade. The rotor with cylindrical blades generally radiated more noise throughout the noise spectrum than did the rotor with airfoil blades. Blowing the blade wake away from the rotor with cylindrical blades did not have any appreciable effect on the amplitude frequency spectrum, and the predominant noise was broadband, either with tunnel wind on or off. For the rotor with airfoil blades, however, blowing the blade wake away changed the character of the noise spectrum completely in that broadband noise was eliminated or diminished to such an extent as to be indistinguishable. The broadband noise of the airfoil-bladed rotor with zero axial velocity is apparently caused by lift fluctuations due to velocity components of the turbulence normal to the plane of rotation.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7623 , L-9349
    Format: application/pdf
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  • 113
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    Improvements to the kernel function method of steady, subsonic lifting surface theory (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The application of a kernel function lifting surface method to three dimensional, thin wing theory is discussed. A technique for determining the influence functions is presented. The technique is shown to require fewer quadrature points, while still calculating the influence functions accurately enough to guarantee convergence with an increasing number of spanwise quadrature points. The method also treats control points on the wing leading and trailing edges. The report introduces and employs an aspect of the kernel function method which apparently has never been used before and which significantly enhances the efficiency of the kernel function approach.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-62327
    Format: application/pdf
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  • 114
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    User's Manual for Computer Program ROTOR (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A detailed description of a computer program to calculate tilt-rotor aircraft dynamic characteristics is presented. This program consists of two parts: (1) the natural frequencies and corresponding mode shapes of the rotor blade and wing are developed from structural data (mass distribution and stiffness distribution); and (2) the frequency response (to gust and blade pitch control inputs) and eigenvalues of the tilt-rotor dynamic system, based on the natural frequencies and mode shapes, are derived. Sample problems are included to assist the user.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-137553 , ASRL-TR-174-2
    Format: application/pdf
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  • 115
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    Aerodynamic damping and oscillatory stability of a model of a proposed HL-10 vehicle in pitch at Mach numbers from 0.20 to 2.86 and in YAW at Mach numbers from 0.20 to 1.20 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Wind tunnel tests of a proposed HL-10 lifting body vehicle were conducted to determine the subsonic and transonic aerodynamic characteristics. The conditions under which the tests were conducted are described. The tests indicate that the configuration has slightly positive damping in pitch except at higher angles of attack at Mach numbers of 0.8, 0.9, and 1.0. At supersonic speeds, the configuration has positive damping in pitch for all test conditions. At subsonic and transonic speed, the configuration has positive damping and positive stability in yaw for all test conditions.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-72619
    Format: application/pdf
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  • 116
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    Subsonic and transonic hinge moment and wing bending/torsion characteristics of .015 scale space shuttle models 49-0 and 67-TS in the Rockwell International trisonic wind tunnel (IA70), volume 3 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: For abstract, see N75-13822.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-134433 , DMS-DR-2175-VOL-3
    Format: application/pdf
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  • 117
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    Subsonic and transonic hinge moment and wing bending/torsion characteristics of .015 scale space shuttle models 49-0 and 67-TS in the Rockwell International trisonic wind tunnel (IA70), volume 2 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: For abstract, see N75-13822.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-134432 , DMS-DR-2175-VOL-2
    Format: application/pdf
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  • 118
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    Application of a parameter identification technique to a hingeless helicopter rotor (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A mathematical model of a gyro-controlled, three-bladed hingeless helicopter rotor was developed and parameters of the model were estimated using a parameter identification technique. The flapping and feathering degrees of freedom of the blades were modeled. The equations of the model contain time-varying, periodic coefficients due to the forward speed of the rotor. A digital simulation of the analytical model was compared with wind-tunnel measurements to establish the validity of the model. Comparisons of steady-state and transient solutions of the analytical model with the tunnel measurements gave reasonably good matching of gyro angle but less satisfactory matching of hub moment measurements. Further improvements were obtained by use of a parameter identification technique to adjust as many as 10 parameters of the analytical model. The sensitivity of the blade response to small changes in the parameters was also calculated.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7834 , A-5289
    Format: application/pdf
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  • 119
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    Experimental study of the effectiveness of cylindrical plume simulators for predicting jet-on boattail drag at Mach numbers up to 1.30 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: An investigation has been conducted in a 16-foot transonic tunnel to determine the effectiveness of utilizing solid circular cylinders to simulate the jet exhaust plume for a series of eight nacelle-mounted isolated circular-arc afterbodies. This investigation was conducted at Mach numbers from 0.40 to 1.30 at an angle of attack of 0. Plume simulators with simulator diameter to nozzle-exit diameter ratios of 0.82, 0.88, 0.98, and 1.00 were investigated. Results of this investigation indicate that use of one of the larger diameter simulators at all Mach numbers would generally result in pressure-coefficient distributions and drag coefficients useful for preliminary design work.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7795 , L-9746
    Format: application/pdf
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  • 120
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    Measurements of the vortex wakes of a subsonic and supersonic transport model in the 40 by 80 foot wind tunnel (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The rolling moment induced on aircraft models in the wake of a model of a subsonic transport and of a supersonic transport was measured as a function of angle of attack for several configurations. The tests are described and an analysis of the data is given in this memorandum.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-62391
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  • 121
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    Investigation of rotor blade element airloads for a teetering rotor in the blade stall regime (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A model of a teetering rotor was tested in a low speed wind tunnel. Blade element airloads measured on an articulated model rotor were compared with the teetering rotor and showed that the teetering rotor is subjected to less extensive flow separation. Retreating blade stall was studied. Results show that stall, under the influence of unsteady aerodynamic effects, consists of four separate stall events, each associated with a vortex shed from the leading edge and sweeping over the upper surface of the rotor blade. Current rotor performance prediction methodology was evaluated through computer simulation.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-137534 , D210-10792-1
    Format: application/pdf
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  • 122
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    Supersonic laminar base pressure, heat-transfer, and upstream influence correlations for small steps (1974)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Some results of the application of a unified theory of small disturbances in nonuniform high-speed boundary layers to the small-step problem for the case of supersonic laminar nonadiabatic flow are described. Comparisons with experimental data are given which show good agreement in a variety of physical features, including useful new base pressure and heat-transfer correlation relations. Using a small perturbation approach, an analytical theory is developed that predicts the steady-state pressure, temperature, and heat-transfer disturbance fields including suction or blowing through the step. Particular emphasis is placed on the important effects of the highly nonuniform flow across the boundary layer, lateral pressure gradients, and the upstream influence associated with viscous-inviscid interaction. Approximate analytical expressions for the wall pressure, skin friction, and heat-transfer perturbations and upstream influence distance are derived by a Fourier transformation approach.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA Journal; 12; Aug. 197
    Format: text
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  • 123
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    Internal hypersonic flow (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-06-27
    Beschreibung: An approach for studying hypersonic internal flow with the aid of a thin-shock-layer approximation is discussed, giving attention to a comparison of thin-shock-layer results with the data obtained on the basis of the imposition theory or a finite-difference integration of the Euler equations. Relations in the case of strong interaction are considered together with questions of pressure distribution and aspects of the boundary-layer solution.
    Schlagwort(e): AERODYNAMICS
    Materialart: ASME PAPER 73-APM-DD , AD-A000739 , AFOSR-74-1643TR
    Format: text
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  • 124
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    Parametric study of near-wake structure of spherical and cylindrical bodies in the laboratory (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-06-27
    Beschreibung: Some aspects of the interaction between metal bodies and streaming rarefied plasmas were studied in a newly constructed plasma wind tunnel as part of an attempt to investigate (via simulation) phenomena relevant to the spacecraft/space plasma interaction. Detailed near-wake ion current profiles for both spherical and cylindrical bodies at different body potentials and at different plasma flow parameters are presented. Various features of the profiles can be correlated, at least qualitatively, with both plasma and body characteristics. The general importance of body geometry is qualitatively demonstrated. In addition, a discussion of the relevance of the above studies to previous in situ data obtained from the Ariel I and Gemini/Agena missions is given.
    Schlagwort(e): AERODYNAMICS
    Materialart: Planetary and Space Science; 22; Mar. 197
    Format: text
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  • 125
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    Extension of a vortex-lattice method to include the effects of leading-edge separation (1974)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Vortex-lattice methods have been used successfully to obtain the aerodynamic coefficients of lifting surfaces without leading-edge separation. It is shown how an existing vortex-lattice method can be modified to include the effects of leading-edge separation. The modified version is then used to calculate the aerodynamic loads on a highly swept delta wing. The results are compared with Peckham's (1958) experimental data.
    Schlagwort(e): AERODYNAMICS
    Materialart: Journal of Aircraft; 11; Feb. 197
    Format: text
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  • 126
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    Wind Tunnel Test of Low Boom Equivalent Body at Mach 4 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A body of revolution, representing the equivalent area distribution of a low boom aircraft design cruising at 24,384 meters at a Mach number of 4, was tested to determine whether its theoretical sonic boom characteristics could be experimentally verified. Results indicate that the essential features of the ground signature are well predicted.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-72013
    Format: application/pdf
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  • 127
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    The Vortex Lattice Method for the Rotor-Vortex Interaction Problem (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The rotor blade-vortex interaction problem and the resulting impulsive airloads which generate undesirable noise levels are discussed. A numerical lifting surface method to predict unsteady aerodynamic forces induced on a finite aspect ratio rectangular wing by a straight, free vortex placed at an arbitrary angle in a subsonic incompressible free stream is developed first. Using a rigid wake assumption, the wake vortices are assumed to move downsteam with the free steam velocity. Unsteady load distributions are obtained which compare favorably with the results of planar lifting surface theory. The vortex lattice method has been extended to a single bladed rotor operating at high advance ratios and encountering a free vortex from a fixed wing upstream of the rotor. The predicted unsteady load distributions on the model rotor blade are generally in agreement with the experimental results. This method has also been extended to full scale rotor flight cases in which vortex induced loads near the tip of a rotor blade were indicated. In both the model and the full scale rotor blade airload calculations a flat planar wake was assumed which is a good approximation at large advance ratios because the downwash is small in comparison to the free stream at large advance ratios. The large fluctuations in the measured airloads near the tip of the rotor blade on the advance side is predicted closely by the vortex lattice method.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-2421
    Format: application/pdf
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  • 128
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    Low-speed aerodynamic characteristics of airfoil sections with rounded trailing edges in forward and reverse flow (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Low-speed wind-tunnel tests were conducted to determine the two-dimensional aerodynamic characteristics of 6-, 12-, and 18-percent-thick airfoil sections with rounded trailing edges in both forward and reverse flow. The shapes incorporated camber with both the leading and trailing edges rounded to provide reasonable aerodynamic performance with either edge directed toward the free-stream flow. The tests were conducted with the airfoils in both normal and reverse orientations relative to the free stream. The Mach number was varied from 0.16 to 0.36 and the angle of attack was varied from minus 10 to 24 million. Reynolds number, based on the airfoil chord, was varied from about 1.0 to 12.0 million.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3060 , L-9327
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  • 129
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    Determination of aerodynamic stability and drag of the Titan 3 C SRM during entry (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: An experimental aerodynamic investigation was conducted in the NASA/MSFC 14-inch Trisonic Wind Tunnel on a 0.00736 scale model of Titan 3 C Solid Rocket Motor (SRM). Static stability and drag data were obtained for Mach numbers of 0.6 to 4.96, angles of attack of minus 10 deg to 190 deg, and roll angles of 0 to 360 deg. The resulting data will be used to predict the dynamic motions of the SRM during entry which will then be compared to flight data. This comparison will improve and lend credibility to methods for predicting the entry dynamics of the space shuttle Solid Rocket Booster (SRB), which is needed for recovery studies and design of the parachute recovery system.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-134402 , DMS-DR-2142
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  • 130
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    Comparison of several methods for predicting separation in a compressible turbulent boundary layer (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Several methods for predicting the separation point for a compressible turbulent boundary layer were applied to the flow over a bump on a wind-tunnel wall. Measured pressure distributions were used as input. Two integral boundary-layer methods, three finite-difference boundary-layer methods, and three simple methods were applied at five free-stream Mach numbers ranging from 0.354 to 0.7325. Each of the boundary-layer methods failed to explicitly predict separation. However, by relaxing the theoretical separation criteria, several boundary-layer methods were made to yield reasonable separation predictions, but none of the methods accurately predicted the important boundary-layer parameters at separation. Only one of the simple methods consistently predicted separation with reasonable accuracy in a manner consistent with the theory. The other methods either indicated several possible separation locations or only sometimes predicted separation.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3102 , E-7802
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  • 131
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    Use of a pitot-static probe for determining wing section drag in flight at Mach numbers from 0.5 to approximately 1.0 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The use of a pitot-static probe to determine wing section drag at speeds from Mach 0.5 to approximately 1.0 was evaluated in flight. The probe unit is described and operational problems are discussed. Typical wake profiles and wing section drag coefficients are presented. The data indicate that the pitot-static probe gave reliable results up to speeds of approximately 1.0.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-56025 , H-844
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  • 132
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    Effect of spanwise blowing on leading-edge vortex bursting of a highly swept aspect ratio 1.18 delta wing (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: An investigation was conducted in the Langley 1/8-scale V/STOL model tunnel on a semispan delta wing with a leading-edge sweep of 74 deg, to determine the effectiveness of various locations of upper surface and reflection plane blowing on leading-edge vortex bursting. Constant area nozzles were located on the wing upper surface along a ray swept 79 deg, which was beneath the leading-edge vortex core. The bursting and reformation of the leading-edge vortex was viewed by injecting helium into the vortex core, and employing a schlieren system.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-71987
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  • 133
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    Investigation of the static lift capability of a low-aspect-ratio wing operating in a powered ground-effect mode (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A preliminary experimental investigation has been made to evaluate the powered ground-effect capability of a low-aspect-ratio, wing-body configuration with forward-mounted propulsion. The tests were limited to static ground-effect conditions in order to obtain information on an air-cushion mode of operation. The results indicate, in general, that an air-cushion mode is within the capability of the type of configuration examined. The conditions examined indicated the possibility of hover mode and also forward acceleration capability in near-ground effect. Center-of-pressure movement did not appear to be a problem. However, it was recognized that longitudinal trim would be a problem to consider in both the hover and acceleration modes.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3031 , L-9368
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  • 134
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    Effects of Reynolds number and model support on the supersonic aerodynamic chacteristics of a 140 deg-included-angle cone (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: An investigation has been made in the Langley Unitary Plan wind tunnel to determine the effects of Reynolds number and sting-support interference on the static aerodynamic characteristics of a 140 deg-included-angle cone. Base pressures and forces and moments of the model were measured at Mach numbers of 1.50, 2.00, 2.94, and 4.00 for ratios of sting diameter to model diameter that varied from 0.125 to 0.500 through an angle-of-attack range from about minus 4 deg to 13 deg. The Reynolds number, based on model diameter 4.80 in. was varied from 161,000 to 415,000.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3019 , L-9383
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  • 135
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    Small scale wind tunnel model investigation of hybrid high lift systems combining upper surface blowing with the internally blown flap (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A small-scale wind tunnel test of a two engine hybrid model with upper surface blowing on a simulated expandable duct internally blown flap was accomplished in a two phase program. The low wing Phase I model utilized 0.126c radius Jacobs/Hurkamp flaps and 0.337c radius Coanda flaps. The high wing Phase II model was utilized for continued studies on the Jacobs/Hurkamp flap. Principal study areas included: basic data both engines operative and with an engine out, control flap utilization, horizontal tail effectiveness, spoiler effectiveness, USB nacelle deflector study and USB/IBF pressure ratio effects.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-114758 , LG74ER0070
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  • 136
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    Subsonic and supersonic indicial aerodynamics and aerodynamic transfer function for complex configurations (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A general theory for indicial-potential-compressible aerodynamics around complex configurations is presented. The motion is assumed to consist of constant subsonic or supersonic speed (steady state) and small perturbations around the steady state. Using the finite-element method to discretize the space problem, a set of differential-difference equations in time relating the potential to its normal derivative on the surface of the body was obtained. The aerodynamics transfer function was derived by using standard method of operational calculus.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-142818 , TN-74-01
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  • 137
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    A finite-element method for lifting surfaces in steady incompressible subsonic flow (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The problem of potential steady subsonic flow for lifting surfaces is considered. This problem requires the solution of an integral equation relating the value of the potential discontinuity on the lifting surface and its wake to the values of the normal derivative of the potential which are known from the boundary conditions. The lifting surface is divided into small (quadrilateral hyperboloidal) surface elements, which are described in terms of the Cartesian components of the four corner points. The values of the potential discontinuity and the normal derivative of the potential are assumed to be constant within each element and equal to their values at the centroids of the elements. This yields a set of linear algebraic equations. Numerical results are in good agreement with existing ones.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-142811 , TR-74-05
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  • 138
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    Acoustic tests of a 15.2 centimeter-diameter potential flow convergent nozzle (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: An experimental investigation of the jet noise radiated to the far field from a 15.2-cm-diam potential flow convergent nozzle has been conducted. Tests were made with unheated airflow over a range of subsonic nozzle exhaust velocities from 62 to 310m/sec. Mean and turbulent velocity measurements in the flow field of the nozzle exhaust indicated no apparent flow anomalies. Acoustic measurements yielded data uncontaminated by internal and/or background noise to velocities as low as 152m/sec. Finally, no significantly different acoustic characteristics between the potential flow nozzle and simple convergent nozzles were found.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-2980
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  • 139
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    Pressure measurements on the leading edge of a swept wing at Mach 2.2 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Detailed pressure measurements were made on a flat semispan swept wing with a rounded leading edge at Mach number 2.2 through a range of Reynolds numbers. Pressure orifices were distributed in the streamwise direction at five spanwise stations on the leading edge and on the upper and lower surfaces. No significant amount of leading-edge suction was found, but the pressures and integrated normal forces on the upper and lower surfaces indicate the presence of a vortex lift.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7506 , L-9185
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  • 140
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    On the use of thick-airfoil theory to design airfoil families in which thickness and lift are varied independently (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A method has been developed for designing families of airfoils in which the members of a family have the same basic type of pressure distribution but vary in thickness ratio or lift, or both. Thickness ratio and lift may be prescribed independently. The method which is based on the Theodorsen thick-airfoil theory permits moderate variations from the basic shape on which the family is based.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7579 , L-9350
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  • 141
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    Aeronautical Engineering: A special bibliography with indexes, supplement 39 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: This special bibliography lists 417 reports, articles, and other documents introduced into the NASA scientific and technical information system in December 1973.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-SP-7037(39)
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  • 142
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    Parameter identifiability of linear dynamical systems (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-06-27
    Beschreibung: It is assumed that the system matrices of a stationary linear dynamical system were parametrized by a set of unknown parameters. The question considered here is, when can such a set of unknown parameters be identified from the observed data? Conditions for the local identifiability of a parametrization are derived in three situations: (1) when input/output observations are made, (2) when there exists an unknown feedback matrix in the system and (3) when the system is assumed to be driven by white noise and only output observations are made. Also a sufficient condition for global identifiability is derived.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Flight Res. Center Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 281-289
    Format: text
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  • 143
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    A unified approach to aircraft parameter identification (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-06-27
    Beschreibung: The most accurate identification results are obtained when all three elements of the identification process - the identification algorithm, the control input, and the instrumentation system - are considered in a unified approach. This type of approach for the design of optimal control inputs and for determining the effect of the instrumentation system, in each case with respect to the identification process is discussed. Design of control inputs which optimize the sensitivity of the system output to the unknown parameters is given. Results using these inputs in an extensive simulation of the identification process indicate they perform measurably better than doublet type inputs. A technique is then presented for specifying an optimal instrumentation system or for determining the effect, the instrumentation system has on the accuracy of the parameter estimates.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Flight Res. Center Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 243-259
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  • 144
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    A square root formulation for the combined state-parameter estimator with application to the identification of sailplane performance (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-06-27
    Beschreibung: A square root formulation is presented for the discrete combined state parameter estimation problem with linear plant dynamics, Gaussian random disturbances, and constant but uncertain parameters. The estimator is a combination of the classical Kalman filter and a maximum likelihood algorithm which maximizes the parameter log-likelihood function using a first order search routine.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Flight Res. Center Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 231-242
    Format: text
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  • 145
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    Analysis of oscillatory pressure data including dynamic stall effects (1974)
    In:  CASI
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    Publikationsdatum: 2019-06-27
    Beschreibung: The dynamic stall phenomenon was examined in detail by analyzing an existing set of unsteady pressure data obtained on an airfoil oscillating in pitch. Most of the data were for sinusoidal oscillations which penetrated the stall region in varying degrees, and here the effort was concentrated on the chordwise propagation of pressure waves associated with the dynamic stall. It was found that this phenomenon could be quantified in terms of a pressure wave velocity which is consistently much less than free-stream velocity, and which varies directly with frequency. It was also found that even when the stall region has been deeply penetrated and a substantial dynamic stall occurs during the downstroke, stall recovery near minimum incidence will occur, followed by a potential flow behavior up to stall inception.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-2394
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  • 146
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    Booster aerodynamic heating: Test support (1974)
    In:  CASI
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    Publikationsdatum: 2019-06-27
    Beschreibung: Several technical areas were encompassed in providing support for booster thermal environment test work. These areas included: (1) cavity flow heating, (2) rarefied flow heating, and (3) impulse operated model research and testing. Cavity flow heating problems were studied with respect to the proposed altitude control motors for the space shuttle. Available literature on this subject was reviewed and analytical predictive methods were summarized for use in planning testing work. Rarefied flow heating data was reviewed and correlated. The study showed the importance of considering rarefied flow conditions in launch thermal environment prediction. Impulse operated model research and testing was conducted to provide a basis for understanding and designing such models for booster thermal environment testing.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-120234 , RTR-008-4
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  • 147
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    FORTRAN program for calculating velocities and streamlines on the hub-shroud mid-channel flow surface of an axial-or mixed-flow turbomachine. 2: Programmer's manual (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A FORTRAN-IV computer program, MERIDL, has been developed that obtains a subsonic or shock-free transonic flow solution on the hub-shroud mid-channel flow surface of a turbomachine. The blade row may be fixed or rotating and may be twisted and leaned. Flow may be axial or mixed, up to 45 deg from axial. Upstream and downstream flow variables can vary from hub to shroud, and provision is made to correct for loss of stagnation pressure. The results include velocities, streamlines, and flow angles on the flow surface and approximate blade surface velocities. Subsonic solutions are obtained by a finite-difference stream-function solution. Transonic solutions are obtained by a velocity-gradient method, using information from a finite-difference stream-function solution at a reduced mass flow.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7344 , E-7516
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  • 148
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    Low speed wind tunnel flow field results for JT8D refan engines on the Boeing 727-200 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Low speed flow angularity results are presented showing flow direction at the nacelle locations on the Boeing 727-200. Flow angle probes (yawheads) were used for measurements at side and center inlet positions on the aft fuselage. A range of flap settings were tested with flap angles of 0 deg, 15 deg, and 40 deg selected for investigation.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-134630 , D6-43098
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  • 149
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    Water table tests of proposed heat transfer tunnels for small turbine vanes (1974)
    In:  CASI
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    Publikationsdatum: 2019-06-27
    Beschreibung: Water-table flow tests were conducted for proposed heat-transfer tunnels which were designed to provide uniform flow into their respective test sections of a single core engine turbine vane and a full annular ring of helicopter turbine vanes. Water-table tests were also performed for the single-vane test section of the core engine tunnel. The flow in the heat-transfer tunnels was shown to be acceptable.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3073 , E-7870
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  • 150
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    Distributed educated throat stability bypass to increase the stable airflow range of a Mach 2.5 inlet with 60-percent internal contraction (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The results of an experimental investigation to increase the stable airflow operating range of a supersonic mixed-compression inlet are presented. A distributed educated throat stability-bypass entrance configuration was tested. In terms of diffuser-exit corrected airflow, a large inlet stable airflow range of about 16.1 percent was obtained if a constant pressure was maintained in the bypass plenum. Limited unstart angle of attack data are presented.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-2975 , E-7708
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  • 151
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    Sound radiation from a high speed axial flow fan due to the inlet turbulence quadrupole interaction (1974)
    In:  CASI
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    Publikationsdatum: 2019-06-27
    Beschreibung: A formula is obtained for the total acoustic power spectra radiated out the front of the fan as a function of frequency. The formula involves the design parameters of the fan as well as the statistical properties of the incident turbulence. Numerical results are calculated for values of the parameters in the range of interest for quiet fans tested at the Lewis Research Center. As in the dipole analysis, when the turbulence correlation lengths become equal to the interblade spacing, the predicted spectra exhibit peaks around the blade passing frequency and its harmonics. There has recently been considerable conjecture about whether the stretching of turbulent eddies as they enter a stationary fan could result in the inlet turbulence being the dominant source of pure tones from nontranslating fans. The results of the current analysis show that, unless the turbulent eddies become quite elongated, this noise source contributes predominantly to the broadband spectrum.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7667 , E-7741
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  • 152
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    An analytical study of the effects of jets located more than one jet diameter above a wing at subsonic speeds (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A procedure has been developed to calculate the effects of blowing two jets over a swept tapered wing at low subsonic speeds. The algorithm used is based on a vortex lattice representation of the wing lifting surface and a line sink-source distribution to simulate the effects of the jet exhaust on the wing lift and drag. The method is limited to those cases where the jet exhaust does not intersect or wash the wing. The predictions of this relatively simple procedure are in remarkably good agreement with experimentally measured interference lift and interference induced drag.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-71965
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  • 153
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    Modern control techniques in active flutter suppression using a control moment gyro (1974)
    In:  CASI
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    Publikationsdatum: 2019-06-27
    Beschreibung: Development of organized synthesis techniques, using concepts of modern control theory was studied for the design of active flutter suppression systems for two and three-dimensional lifting surfaces, utilizing a control moment gyro (CMG) to generate the required control torques. Incompressible flow theory is assumed, with the unsteady aerodynamic forces and moments for arbitrary airfoil motion obtained by using the convolution integral based on Wagner's indicial lift function. Linear optimal control theory is applied to find particular optimal sets of gain values which minimize a quadratic performance function. The closed loop system's response to impulsive gust disturbances and the resulting control power requirements are investigated, and the system eigenvalues necessary to minimize the maximum value of control power are determined.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-138494 , SU-DAAR-474
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  • 154
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    Distributed porous throat stability bypass to increase the stable airflow range of a Mach 2.5 inlet with 60 percent internal contraction (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The results of an experimental investigation to increase the stable airflow operating range of a supersonic, mixed-compression inlet with 60-percent internal contraction are presented. Various distributed-porous, throat stability-bypass entrance configurations were tested. In terms of diffuser-exit corrected airflow, a large inlet stable airflow range of about 25 percent was obtained with the optimum configuration if a constant pressure was maintained in the by-pass plenum. The location of the centerbody bleed region had a decided effect on the overall inlet performance. Limited unstart angle-of-attack data are presented.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-2974 , E-7707
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  • 155
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    Preliminary static tests of a simulated upper-surface blown jet-flap configuration utilizing a full-size turbofan engine (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The investigation was conducted to evaluate the static turning performance and the pressure and temperature environment of an upper-surface-blown wing and flap utilizing a small turbofan engine. The tests involved modifications of the engine primary nozzle designed to alleviate high temperature problems on the wing and flaps and yet provide acceptable static turning performance over the desired range of flap deflections and thrust conditions.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-71931
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  • 156
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    An investigation of several NACA 1 series axisymmetric inlets at Mach numbers from 0.4 to 1.29 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: An investigation was conducted in the Langley 16-foot transonic tunnel to determine the performance of seven inlets having NACA 1-series contours and one inlet having an elliptical contour over a range of mass-flow ratios and at angle of attack. The inlet diameter ratio varied from 0.81 to 0.89; inlet length ratio varied from 0.75 to 1.25; and internal contraction ratio varied from 1.009 to 1.093. Reynolds number based on inlet maximum diameter varied from 3.4 million at a Mach number of 0.4 to 5.6 million at a Mach number of 1.29.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-2917 , L-8588
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  • 157
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    Preliminary results of flight tests of vortex attenuating splines (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Flight tests have been conducted to evaluate the effectiveness of a wingtip vortex attenuating device, referred to as a spline. Vortex penetrations were made with a PA-28 behind a C-54 aircraft with and without wingtip splines attached and the resultant rolling acceleration was measured and related to the roll acceleration capability of the PA-28. Tests were conducted over a range of separation distances from about 5 nautical miles (n. mi.) to less than 1 n. mi. Preliminary results indicate that, with the splines installed, there was a significant reduction in the vortex induced roll acceleration experienced by the PA-28 probe aircraft, and the distance at which the PA-28 roll control became ineffective was reduced from 2.5 n. mi. to 0.6 n. mi., or less. There was a slight increase in approach noise (approximately 4 db) with the splines installed due primarily to the higher engine power used during approach. Although splines significantly reduced the C-54 rate of climb, the rates available with four engines were acceptable for this test program. Splines did not introduce any noticeable change in the handling qualities of the C-54.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-71928
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  • 158
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    Pressure-loss and flow coefficients inside a chordwise-finned, impingement, convection, and film air-cooled turbine vane (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Total-pressure-loss coefficients, flow discharge coefficients, and friction factors were determined experimentally for the various area and geometry changes and flow passages within an air-cooled turbine vane. The results are compared with those of others obtained on similar configurations, both actual and large models, of vane passages. The supply and exit air pressures were controlled and varied. The investigation was conducted with essentially ambient-temperature air and without external flow of air over the vane.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3028 , E-7719
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  • 159
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    Research turbine for high-temperature core engine application. 2: Effect of rotor tip clearance on overall performance (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A 25.4-cm (10-in) tip diameter turbine was tested to determine the effect of rotor radial tip clearance on turbine overall performance. The test turbine was a half-scale model of a 50.8-cm-(20-in.-) diameter research turbine designed for high-temperature core engine application. The test turbine was fabricated with solid vanes and blades with no provision for cooling air and tested at much reduced inlet conditions. The tests were run at design speed over a range of pressure ratios for three different rotor clearances ranging from 2.3 to 6.7 percent of the annular blade passage height. The results obtained are compared to the results obtained with three other turbines of varying amounts of reaction.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7639 , E-7728
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  • 160
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    Cold-air investigation of a turbine for high temperature-engine application. 5: Two-stage turbine performance as affected by variable stator area (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The stator areas of the design two-stage turbine were both decreased and increased by nominally 30 percent, and the performances of the two turbines are compared with that of the design stator area turbine. Turbine efficiency decreased with stator area changes. Closing the stator area resulted in the more severe efficiency loss. The decrease in efficiency for both turbines is attributable to rotor incidence, off-design blade-surface velocities, and adverse reaction changes across the blade rows.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7571 , E-7671
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  • 161
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    An experimental investigation of leading-edge vortex augmentation by blowing (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A wind tunnel test was conducted to determine the effects of over-the-wing blowing as a means of augmenting the leading-edge vortex flow of several pointed-tip, sharp-edged planforms. Arrow, delta, and diamond wings with leading-edge sweeps of 30 and 45 degrees were mounted on a body-of-revolution fuselage and tested in a low-speed wind tunnel at a Mach number of 0.2. Nozzle location data, pitch data, and flow-visualization pictures were obtained for a range of blowing rates. Results show pronounced increases in vortex lift due to the blowing.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-132415
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  • 162
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    Input description for Jameson's three-dimensional transonic airfoil analysis program (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The input parameters are presented for a computer program which performs calculations for inviscid isentropic transonic flow over three dimensional airfoils with straight leading edges. The free stream Mach number is restricted only by the isentropic assumption. Weak shock waves are automatically located where they occur in the flow. The finite difference form of the full equation for the velocity potential is solved by the method of relaxation, after the flow exterior to the airfoil is mapped to the upper half plane.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-71919
    Format: application/pdf
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  • 163
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    Low-speed aerodynamic characteristics of a 13.1-percent-thick, high-lift airfoil (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Low speed sectional characteristics of a high lift airfoil are studied and a comparison is made of those characteristics with the predictions of the theoretical methods used in the airfoil's design. The 13.1 percent-thick, UI-1720 airfoil was found to achieve the predicted maximum lift coefficient of nearly 2.0. No upper-surface, flow separation was found below the stall angle of attack of 16 degrees; it appeared that stall was due to an abrupt leading edge flow separation.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-153937 , SAE-740366 , Business Aircraft Meeting; Apr 02, 1974 - Apr 05, 1974; Wichita, KS; United States
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  • 164
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    A computing method for sound propagation through a nonuniform jet stream (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: The classical formulation of sound propagation through a jet flow was found to be inadequate for computer solutions. Previous investigations selected the phase and amplitude of the acoustic pressure as dependent variables requiring the solution of a system of nonlinear algebraic equations. The nonlinearities complicated both the analysis and the computation. A reformulation of the convective wave equation in terms of a new set of dependent variables is developed with a special emphasis on its suitability for numerical solutions on fast computers. The technique is very attractive because the resulting equations are linear in nonwaving variables. The computer solution to such a linear system of algebraic equations may be obtained by well-defined and direct means which are conservative of computer time and storage space. Typical examples are illustrated and computational results are compared with available numerical and experimental data.
    Schlagwort(e): AERODYNAMICS
    Materialart: Acoustical Society of America, Meeting; Nov 04, 1974 - Nov 08, 1974; St. Louis, MO
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  • 165
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    Aerodynamic drag reduction tests on a full-scale tractor-trailer combination with several add-on devices (1974)
    In:  CASI
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    Publikationsdatum: 2019-07-13
    Beschreibung: Aerodynamic drag tests were performed on a conventional cab-over-engine tractor with a 45-foot trailer and five commercially available or potentially available add-on devices using the coast-down method. The tests ranged in velocity from approximately 30 miles per hour to 65 miles per hour and included some flow visualization. A smooth, level runway at Edwards Air Force Base was used for the tests, and deceleration measurements were taken with both accelerometers and stopwatches. An evaluation of the drag reduction results obtained with each of the five add-on devices is presented.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-56028 , Reduction of Aerodynamic Drag of Trucks Conf.; Oct 10, 1974 - Oct 11, 1974; Pasadena, CA; United States
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  • 166
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    Three dimensional flows around airfoils with shocks (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: The present work describes a mathematical model and numerical scheme for the computer-aided calculation of two- and three-dimensional transonic flow over an isolated yawed wing with oblique shock waves and a trailing vortex sheet. The flow is modeled by the potential equation for irrotational flow which is hyperbolic at supersonic points and elliptic at subsonic points. A coordinate-invariant difference scheme is used in which retarded difference formulas are constructed to conform with the local flow direction. The resulting 'rotated' difference scheme allows complete flexibility in the choice of a coordinate system. Shock waves are located automatically in the form of compression bands spread over a few mesh widths. The scheme has proven to be stable and convergent throughout the transonic range. Calculations have been performed for Mach number up to 1.2 and yaw angles up to 60 deg, the likely operating range of a yawed-wing transport designed to fly at supersonic speeds. Calculations becomes less accurate towards upper end of range, because the difference scheme is first-order accurate in the supersonic range.
    Schlagwort(e): AERODYNAMICS
    Materialart: International Symposium on Computing methods in applied sciences and engineering; Dec 17, 1973 - Dec 21, 1973; Versailles; France
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  • 167
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    Supercirculation effects induced by vectoring a partial-span rectangular jet (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: Thrust-induced supercirculation effects from thrust vectoring have indicated a potential for not only increasing maneuverability of fighter aircraft but also as a means of improving cruise performance. The current study investigated a partial-span rectangular jet-exhaust nozzle located at the wing trailing edge that acts similar to a jet flap by increasing lift due to supercirculation. This paper summarizes experimental studies including the effects of nozzle deflection angle, wing camber, and nozzle shape and exit location on lift, drag and load distributions. The results indicate that significant increases in thrust-induced lift along with substantial decreases in drag are possible.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA PAPER 74-971 , Aircraft Design, Flight Test and Operations Meeting; Aug 12, 1974 - Aug 14, 1974; Los Angeles, CA
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  • 168
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    Investigation of acoustic radiation from supersonic turbulent jets by double-pulse holographic interferometry (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: A new experimental method was used to optically investigate the acoustic field radiated from supersonic jets. The method utilizes a pulse ruby laser to obtain double exposure holograms of the sound field of a supersonic jet. The jet remains on during both exposures thus eliminating the no-flow exposure. The time separation between the pulses can be varied depending on the spectral component of the radiation to be observed. Optical records were obtained for supersonic jets with exit Mach number 1.0, 1.5 and 2.0. It was found that high frequency acoustic radiation mainly originates from the regions near the nozzle exit, whereas the low frequency noise is generated from regions further downstream. These findings are consistent with the acoustic data obtained by other investigators.
    Schlagwort(e): AERODYNAMICS
    Materialart: Meeting of the Acoustical Society of America; Apr 23, 1974 - Apr 26, 1974; New York, NY
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  • 169
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    Theoretical considerations of some nonlinear aspects of hypersonic panel flutter (1974)
    In:  CASI
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    Publikationsdatum: 2019-07-13
    Beschreibung: A research project to analyze the effects of hypersonic nonlinear aerodynamic loading on panel flutter is reported. The test equipment and procedures for conducting the tests are explained. The effects of aerodynamic linearities on stability were evaluated by determining constant-initial-energy amplitude-sensitive stability boundaries and comparing them with the corresponding linear stability boundaries. An attempt to develop an alternative method of analysis for systems where amplitude-sensitive instability is possible is presented.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-140896 , SU-DAAR-491
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  • 170
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    Investigation of the Kline-Fogleman airfoil section for rotor blade applications (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Wind tunnel tests of a wedgeshaped airfoil with sharp leading edge and a spanwise step were conducted. The airfoil was tested with variations of the following parameters: (1) Reynolds number, (2) step location, (3) step shape, (4) apex angle, and (5) with the step on either the upper or lower surface. The results are compared with a flat plate and with wedge airfoils without a step having the same aspect ratio. Water table tests were conducted for flow visualization and it was determined that the flow separates from the upper surface at low angles of attack. The wind tunnel tests show that the lift/drag ratio of the airfoil is lower than for a flat plate and the pressure data show that the airfoil derives its lift in the same manner as a flat plate.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-141282 , AE-74-1054-1
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  • 171
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    The response of an axial compressor to unsteady disturbances (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: The disturbances of flow in a uniform duct are examined, taking into account a disturbance which is sinusoidal in time. The equations of motion for a plane disturbance with blade forces represented by body forces are considered along with the stage configuration of the compressor and the temperature rise for two-dimensional flow through the stage. An investigation is conducted for the case in which the disturbances are restricted to small amplitudes about the design operating condition for all points within the compressor. The three independent solutions of the disturbance equations obtained for the system of compressor and associated inlet and exit ducts can be used with three arbitrary constants to satisfy three external conditions.
    Schlagwort(e): AERODYNAMICS
    Materialart: Interagency Symposium on University Research in Transportation Noise; Jun 05, 1974 - Jun 07, 1974; Raleigh, NC
    Format: text
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  • 172
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    Aerodynamic and acoustic performance of ejectors for engine-under-the-wing concepts (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: Subsonic thrust augmentation, exhaust plume velocity contours and acoustic characteristics of a small-scale, 6-tube mixer nozzle with ejector were obtained with and without a wing. Thrust augmentation up to 30 percent was achieved. Aerodynamic results showed that at a given location, greater downstream velocities are obtained with an ejector than with the baseline nozzle. Ejectors reduce high frequency noise; however, low-frequency noise amplification also occurs. Acoustic reflections off the wing increase the noise level to a ground observer. With an ejector, the acoustic benefits of forward velocity may be significantly reduced compared with the baseline nozzle.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA PAPER 74-950 , Aircraft Design, Flight Test and Operations Meeting; Aug 12, 1974 - Aug 14, 1974; Los Angeles, CA
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  • 173
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    An experimental and theoretical study of low-aspect ration swept and oblique wings at Mach numbers between 0.6 and 1.4 (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: Experimental forces and moments for two wing-body combinations having (a) a swept wing and (b) an oblique wing are compared. At all Mach numbers, the oblique wing (at its optimum sweep angle) had higher maximum lift-to-drag ratios than the fixed, swept wing. At high angles of attack, the direction of the pitching or rolling tendencies of the oblique wing was a function of the spanwise distribution of wing bend or washout for the two bends being investigated. At low angles of attack, linear theory gave satisfactory predictions of the subsonic lift-curve slope, the aerodynamic-center travel with Mach number, and the maximum lift-to-drag ratio.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA PAPER 74-771 , Mechanics and Control of Flight Conference; Aug 05, 1974 - Aug 09, 1974; Anaheim, CA
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  • 174
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    Cross-correlation methods for studying near- and far-field noise characteristics of several flow-surface interaction problems (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: Systematic methods based on cross-correlation techniques are presented for experimental studies of near- and far-field noise characteristics of airflow-surface interaction problems. By cross-correlating any two of three-kinds of microphone measurements: one flush-mounted on the surface, one located in the near field, and one placed in the far field, far-field noise intensities and near-field acoustic energy fluxes can be determined. In both near and far fields, the noise characteristics due to the flow turbulence and surface fluctuating pressure contributions can be evaluated separately. Specific applications to the noise field generated by impinging jets, by surface blowing jets, and by turbulent flow over trailing edges are discussed.
    Schlagwort(e): AERODYNAMICS
    Materialart: Meeting of the Acoustical Society of America; Apr 23, 1974 - Apr 26, 1974; New York, NY
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  • 175
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    Propagation of plane waves in a variable area duct carrying a compressible subsonic flow (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: A complete numerical solution is obtained for plane wave propagation in a variable-area duct which carries a mean compressible flow. The equation solved is a matrix formulation of the equations first derived by Tsien in 1952. Sample calculations are presented for four particular flow configurations: (1) a duct-nozzle-duct combination with the acoustic wave traveling with the flow, (2) a duct-nozzle-duct combination with the acoustic wave traveling against the flow, (3) an inlet-nozzle-duct configuration with the acoustic wave traveling against the flow, and (4) a duct-nozzle-exit configuration with the acoustic wave traveling with the flow. For each of these cases, the variation of energy flux with frequency is shown for particular geometry and flow condition.
    Schlagwort(e): AERODYNAMICS
    Materialart: Meeting of the Acoustical Society of America; Apr 23, 1974 - Apr 26, 1974; New York, NY
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  • 176
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    An experimental and analytical study of slip and catalytic boundary conditions applied to spheres in low Reynolds number arc jet flows (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: Measurements of low-density dissociated arc-heated flows around low and high surface catalycity spheres are compared with numerical solutions to the full Navier-Stokes equations for reacting gas flow fields, taking into account slip and finite surface catalytic boundary conditions. A time-dependent finite difference solution technique developed by Li (1973, 1974) is used in the investigation and a simple transport model is employed for the flows considered. The correctness of the solution approach is demonstrated by the very good agreement obtained between experimental and computational data.
    Schlagwort(e): AERODYNAMICS
    Materialart: International Symposium on Rarefied gas dynamics; Jul 15, 1974 - Jul 20, 1974; Goettingen; Germany
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  • 177
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    Development of inverse inviscid transonic solution methods (1974)
    In:  CASI
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    Publikationsdatum: 2019-07-13
    Beschreibung: A numerical method suitable for the analysis and/or design of supercritical transonic airfoils is reported. In order to achieve accuracy, the method utilizes the full inviscid potential flow equations; and in order to remain simple it solves the problem in a stretched Cartesian grid system. The resulting computer program has several advantages over others of its type -- its use in either the direct analysis mode in which the airfoil shape is prescribed and the flow field and surface pressures are determined, or in the inverse mode in which the surface pressures are given and the airfoil shape and flow field are computed. Other advantages of the program include its use in a design program, the rotated finite difference scheme and its determination of the airfoil shape simultaneously with the flow field relaxation solution.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-142016 , TAMRF-3033-7403
    Format: application/pdf
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  • 178
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    NASA flight research on aircraft wake vortices and minimization concepts (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA PAPER 74-953 , Aircraft Design, Flight Test and Operations Meeting; Aug 12, 1974 - Aug 14, 1974; Los Angeles, CA
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  • 179
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    Review of NASA supercritical airfoils (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: NASA supercritical airfoils are characterized by a substantially reduced curvature of the midcord region of the upper surface together with increased camber near the trailing edge. The basic aerodynamic phenomena associated with the airfoils and representative wind tunnel results are discussed. The results indicate that the drag rise Mach numbers for NASA supercritical airfoils are 0.1 higher than for comparable NACA 6-series airfoils. A recent analytic method for predicting the aerodynamic characteristics of supercritical airfoils is described. The flight demonstration programs of three applications of supercritical airfoils utilizing the F-8, T-2C and F-111 as test beds are summarized.
    Schlagwort(e): AERODYNAMICS
    Materialart: ICAS PAPER 74-10 , International Council of the Aeronautical Sciences Congress; Aug 25, 1974 - Aug 30, 1974; Haifa; Israel
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  • 180
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    Experimental and analytical sonic nozzle discharge coefficients for Reynolds numbers up to 8,000,000 (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: Sonic discharge coefficients are presented for two different geometry flow nozzles using nitrogen gas at high pressures where real-gas corrections are significant. Throat Reynolds number range extended up to 8,000,000. Experimentally obtained coefficients for a nozzle with a continuous and finite radius of curvature agreed with those obtained analytically to within 0.2 per cent. Experimental coefficients for a long-radius ASME nozzle agreed to within 0.25 per cent to an empirical equation representing the most probable subsonic discharge coefficient.
    Schlagwort(e): AERODYNAMICS
    Materialart: ASME PAPER 74-WA/FM-8 , American Society of Mechanical Engineers, Winter Annual Meeting; Nov 17, 1974 - Nov 22, 1974; New York, NY
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  • 181
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    Nonlinearities in analyses of unsteady flow around oscillating wings (1974)
    In:  Other Sources
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    Publikationsdatum: 2019-07-13
    Beschreibung: An analysis of nonlinearities involved in unsteady subsonic viscous flow around wings at high Reynolds numbers is presented. The finite element method was applied for the numerical integration of the vorticity transport equations. Physical and numerical aspects of the nonlinearities are discussed. Magnification of nonlinearities in the convection terms near wing surfaces due to changing geometry at leading and trailing edges of the wing chord is determined. As a bubble is generated near the leading edge, the timewise variation of vorticity and pressure distributions over the surface is shown. The different procedures for the integration of the vorticity transport equations in three dimensions along spanwise, chordwise, and normal directions are discussed.
    Schlagwort(e): AERODYNAMICS
    Materialart: Computational methods in nonlinear mechanics; International Conference; Sep 23, 1974 - Sep 25, 1974; Austin, TX
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  • 182
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    Aerodynamic influence coefficient method using singularity splines (1974)
    In:  CASI
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    Publikationsdatum: 2019-07-13
    Beschreibung: A numerical lifting surface formulation, including computed results for planar wing cases is presented. This formulation, referred to as the vortex spline scheme, combines the adaptability to complex shapes offered by paneling schemes with the smoothness and accuracy of loading function methods. The formulation employes a continuous distribution of singularity strength over a set of panels on a paneled wing. The basic distributions are independent, and each satisfied all the continuity conditions required of the final solution. These distributions are overlapped both spanwise and chordwise. Boundary conditions are satisfied in a least square error sense over the surface using a finite summing technique to approximate the integral. The current formulation uses the elementary horseshoe vortex as the basic singularity and is therefore restricted to linearized potential flow. As part of the study, a non planar development was considered, but the numerical evaluation of the lifting surface concept was restricted to planar configurations. Also, a second order sideslip analysis based on an asymptotic expansion was investigated using the singularity spline formulation.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-2423 , D6-41093
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  • 183
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    Scale drogue parachute model (1974)
    In:  CASI
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    Publikationsdatum: 2019-07-13
    Beschreibung: Drogue parachute models, pilot parachute models, and their deployment bags were fabricated incorporating recommended design changes. These changes are described in detail.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-120719 , GER-16130
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  • 184
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    Wind tunnel tests of a symmetrical airfoil with scoop fed slots (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The design and wind tunnel test of a model vertical tail fin is described in this report. The model is designed to provide the aerodynamic forces necessary for lateral stabilization without moving parts or a separate source of power. It employs scoop-fed slots on both surfaces of the symmetrical airfoil. They are to be controlled differentially by means of a fluidic amplifier to implement an automatic fulltime lateral stabilization system. The results of tests show that the control of forces is stable and quite linear in various modes of operation. Significant forces were produced that can be increased as necessary by increasing slot size and scoop size. Slots can be located ahead of the conventional rudder and the scoop can be at the base of the vertical tail fin to avoid the need for major changes in conventional aircraft design. The first phase of the work demonstrated the feasibility of no-moving-parts aircraft control. The second phase established that a practical fluidic amplifier can be built to control slot flows from fluidic signals. Recommendations are made to optimize the design of the fluidic amplifier and to characterize its dynamic response in support of further analytical studies.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-132568 , FIRL-C-3741-2
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  • 185
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    Inviscid to turbulent transition of trailing vortices (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The characteristics of the plateau region in the vortex system which trails from a lifting wing are discussed. The decay of the vortex due to viscous or turbulent shear is very slow in the plateau so that the maximum tangential speed in the vortices remains nearly constant for some distance downstream of roll-up and then begins to decrease, becoming inversely proportional to the square root of the distance downstream. Mathematical models are developed to analyze the structure of the plateau area. Solutions are obtained for both constant and variable eddy viscosity models.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-142298 , ISU-ERI-AMES-74241
    Format: application/pdf
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  • 186
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    Theoretical and experimental study on the ejector augmented jet flap (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The analytical concept used in determining the characteristics of jet flap or related propulsive systems suitable for VTOL and STOL applications was examined. The configuration chosen was a two dimensional wing with a biplane flap, having a jet injected on the upper surface of the wing at the flap hinge axis and discharging into the channel between the two elements of the flap. The experimental work was conducted in a two dimensional test installation in a subsonic wind tunnel. The model description, the test conditions, and a summary of the experimental results are presented.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-136749
    Format: application/pdf
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  • 187
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    Conduct overall test operations and evaluate two Doppler systems to detect, track and measure velocities in aircraft wake vortices (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A program plan for system evaluation of the two-dimensional Scanning Laser Doppler System (SLDS) is presented. In order to meet system evaluation and optimization objectives the following tests were conducted: (1) noise tests; (2) wind tests; (3) blower flowfield tests; (4) single unit (1-D) flyby tests; and (5) dual unit (2-D) flyby tests. Test results are reported. The final phase of the program included logistics preparation, equipment interface checkouts, and data processing. It is concluded that the SLDS is capable of accurately tracking aircraft wake vortices from small or large aircraft, and in any type of weather.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-120600 , LMSC-HREC-TR-D390470
    Format: application/pdf
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  • 188
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    Power requirement of rotating rods in airflow (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Experiments were performed to determine the power required for rotating a rotor disc fitted with a number of radially arranged rods placed into a ducted airflow. An array of stationary rods, also radially arranged, were placed upstream close to the rotor with a small gap between the rods to cause wake interference. The results show that power increased with increasing airflow and the rate of increase varied considerably. At lower values of airflow the rate of increase was larger than at higher airflow and definite power peaks occurred at certain airflow rates, where the power attained a maximum within the test airflow range. During the test a maximum blade passage frequency of 2037 Hz was attained.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-132556 , TR-74-M6
    Format: application/pdf
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  • 189
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    Subsonic and transonic hinge moment and wing bending/torsion characteristics of .015 scale space shuttle models 49-0 and 67-TS in the Rockwell International trisonic wind tunnel (IA70), volume 1 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Experimental aerodynamic investigations were conducted on an 0.015-scale representation of the integrated space shuttle launch vehicle in the trisonic wind tunnel. The primary test objective was to obtain subsonic and transonic elevon and bodyflap hinge moments and wing bending-torsion moments in the presence of the launch vehicle. Wing pressures were also recorded for the upper and lower right wing surfaces at two spanwise stations. The hinge moment, wing bending/torsion moments and wing pressure data were recorded over an angle-of-attack (alpha) range from -8 deg to +8 deg, and angle-of-sideslip (beta) range from -8 deg to +8 deg and at Mach numbers of 0.90, 1.12, 1.24 and 1.50. Tests were also conducted to determine the effects of the orbiter rear attach cross beam and the forward attach wedge and strut diameter. The orbiter alone was tested at 0.90 and 1.24 Mach number only.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-134431 , DMS-DR-2175-VOL-1
    Format: application/pdf
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  • 190
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    Numerical solution for unsteady sonic flow over thin wings (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A numerical solution precedure of a simplified unsteady transonic equation which is fast, reasonably accurate, and takes into account many of the effects of the steady flow field is described. The numeric solution of this equation is accurate and is accomplished on an IBM 360/65 computer. Arbitrary planform shape is accommodated and variable local Mach number effects from the steady flow are easily handled.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-CR-141114
    Format: application/pdf
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  • 191
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    Experimental aerodynamic characteristics for a cylindrical body of revolution with various noses at angles of attack from 0 deg to 58 deg and Mach numbers from 0.6 to 2.0 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: An experimental investigation was conducted to determine the effect of forebody geometry, a grit ring around the nose, Reynolds number, Mach number, and angle of attack on the aerodynamic characteristics of a body of revolution. Aerodynamic force and moment characteristics were measured for a cylindrical body with tangent ogive noses of fineness ratio 2.5, 3.0, 3.5, and 5.0. The cylindrical body was tested with an ogive nose having a rounded tip and an ogive nose with two different nose strake arrangements. Aerodynamic configurations were tested at various Mach numbers, angles of attack, and Reynolds numbers. The data demonstrate that the aerodynamic characteristics for a body of revolution can be significantly affected by changes in nose fineness ratio, nose bluntness, Reynolds number, Mach number, and, of course, angle of attack. Nose strakes increased the normal forces but had little effect on the side forces that developed at subsonic Mach numbers for alpha greater than about 25. A grit ring around the nose had little or no effect on the aerodynamic characteristics.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3128 , A-5746
    Format: application/pdf
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  • 192
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    A wind tunnel investigation of the wake near the trailing edge of a deflected externally blown flap (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The model tested was a general research model of a swept-wing, jet-powered STOL transport with externally blown flaps. The model was tested with four engine simulators mounted on pylons under the wing. Tests were conducted in the V/STOL tunnel over an angle of attack range of 0 deg to 16 deg and a thrust coefficient range from 0 to approximately 4 at a Reynolds number of 0.461 x 1 million based on the wing reference chord. The results of this investigation are presented primarily as plots of the individual velocity vectors obtained from the wake survey. These data are used to extend an earlier analysis to isolate the effects of the engine thrust on the behavior of the flow at the flap trailing edge. Results of a comparison with a jet-flap theory are also shown.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3079 , L-9665
    Format: application/pdf
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  • 193
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    Aerodynamic roll damping of a T-tail transport configuration (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The aerodynamic roll damping and the yawing moment due to roll rate for a model of a T-tail transport with aft-mounted engines were measured by means of a small-amplitude forced-oscillation mechanism. The tests were made for Mach numbers between 0.21 and 0.80 over a range of angles of attack from about minus 4 deg to 22 deg. The basic configuration had positive damping in roll at low angles of attack with regions of low positive and negative damping for angles of attack above 8 deg to 10 deg. There was good agreement between the theoretical estimates of the roll damping for the wing alone and the experimental results at an angle of attack of 0 deg for Mach numbers of 0.60 and less. The T-tail configuration and the engine nacelles mounted aft on the fuselage did not significantly affect either the damping in roll or the yawing moment due to roll rate.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-3115 , L-9378
    Format: application/pdf
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  • 194
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    Effects of leading edge sweep angle and design lift coefficient on performance of a modified arrow wing at a design Mach number of 2.6 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Wing models were tested in the high-speed section of the Langley Unitary Plan wind tunnel to study the effects of the leading-edge sweep angle and the design lift coefficient on aerodynamic performance and efficiency. The models had leading-edge sweep angles of 69.44 deg, 72.65 deg, and 75.96 deg which correspond to values of the design Mach-number-sweep-angle parameter (beta cotangent A) sub DES of 0.6, 0.75, and 0.9, respectively. For each sweep angle, camber surfaces having design lift coefficients of 0,0.08, and 0.12 at a design Mach number of 2.6 were generated. The wind-tunnel tests were conducted at Mach numbers of 2.3, 2.6, and 2.96 with a stagnation temperature of 338.7 K (150 F) and a Reynolds number per meter of 9.843 times 10 to the 6th power. The results of the tests showed that only a moderate sweeping of the wing leading edge aft of the Mach line along with a small-to-moderate amount of camber and twist was needed to significantly improve the zero-lift (flat camber surface) wing performance and efficiency.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7753 , L-9446
    Format: application/pdf
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  • 195
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    An exploratory flight investigation of helicopter sling-load placements using a closed-circuit television as a pilot aid (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Helicopter sling load operations have been limited during pick up and delivery of external cargo by the lack of precision achieved by the combination of pilot, helicopter, and sling load. Use of a closed circuit television as a pilot aid during sling load delivery and placement was documented along with additional cases representing procedures currently employed by military and commercial operators. Although an increase in pilot workload was noted when the television system was used, the results indicated a comparable level of performance for each test case.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7776 , L-9744
    Format: application/pdf
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  • 196
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    A parametric study of effect of forebody shape on flow angularity at Mach 8 (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Flow angularity and static pressure measurements have been made on the lower surface of nine forebody models that simulate the bottom forward surface of a hypersonic aircraft. Measurements were made in an area of the forebody that represents the location of an inlet of a scramjet engine. A parametric variation of the forebody surface investigated the effect of: (1) spanwise curvature; (2) longitudinal curvature; and (3) planform shape on both flow angularity and static pressure distribution. Results of each of the three parametric variations of geometry were compared to those for the same flat delta forebody. Spanwise curvature results showed that a concave shape and the flat delta had the lowest flow angularity and lowest rate of increase in flow angularity with angle of attack. Longitudinal curvature results showed a convex surface to give the better flow at the higher angles of attack. The better of the two planform shapes tested was a convex elliptical shape. Limited flow field calculations were made at angles of attack using a three dimensional, method-of-characteristics program. In general, at all angles of attack there was agreement between data and theory.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7768 , L-9639
    Format: application/pdf
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  • 197
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    Wind tunnel tests of modified cross, hemisflo, and disk-gap-band parachutes with emphasis in the transonic range (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: Transonic wind-tunnel studies were conducted with modified cross, hemisflo, and disk-gap-band parachute models in the wake of a cone-cylinder shape forebody. The basic cross design was modified with the addition of a circumferential constraining band at the lower edge of the canopy panels. The tests covered a Mach number range of 0.3 to 1.2 and a dynamic pressure range from 479 Newtons per square meter to 5746 Newtons per square meter. The parachute models were flexible textile-type structures and were tethered to a rigid forebody with a single flexible riser. Different size models of the modified cross and disk-gap-band canopies were tested to evaluate scale effects. Model reference diameters were 0.30, 0.61, and 1.07 meters (1.0, 2.0, and 3.5 ft) for the modified cross; and nominal diameters of 0.25 and 0.52 meter (0.83 and 1.7 ft) for the disk-gap-band; and 0.55 meter (1.8 ft) for the hemisflo. Reefing information is presented for the 0.61-meter-diameter cross and the 0.52-meter-diameter disk-gap-band. Results are presented in the form of the variation of steady-state average drag coefficient with Mach number. General stability characteristics of each parachute are discussed. Included are comments on canopy coning, spinning, and fluttering motions.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7759 , L-9421
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  • 198
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    Extraction from flight data of lateral aerodynamic coefficients for F-8 aircraft with supercritical wing (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A parameter-extraction algorithm was used to determine the lateral aerodynamic derivatives from flight data for the F-8 aircraft with supercritical wing. The flight data used were the recorded responses to aileron or rudder pulses for Mach numbers of 0.80, 0.90, and 0.98. Results of this study showed that a set of derivatives were determined which yielded a calculated aircraft response almost identical with the response measured in flight. Derivatives extracted from motion resulting from rudder inputs were somewhat different from those resulting from aileron inputs. It was found that the derivatives obtained from the rudder-input data were highly correlated in some instances. Those from the aileron input had very low correlations and appeared to be the more reliable.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TN-D-7749 , L-9619
    Format: application/pdf
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  • 199
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    Some factors affecting the use of lighter than air systems (1974)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The uses of lighter-than-air vehicles are examined in the present day transportation environment. Conventional dirigibles were found to indicate an undesirable economic risk due to their low speeds and to uncertainties concerning their operational use. Semi-buoyant hybrid vehicles are suggested as an alternative which does not have many of the inferior characteristics of conventional dirigibles. Economic and performance estimates for hybrid vehicles indicate that they are competitive with other transportation systems in many applications, and unique in their ability to perform some highly desirable emergency missions.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA-TM-X-62374
    Format: application/pdf
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  • 200
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    Lifting surface theory of axial compressor blade rows. I - Subsonic compressor. II - Transonic compressor (1974)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: A linearized three-dimensional lifting surface theory is considered, taking into account relations to axisymmetric 'through-flow' or actuator disk theories, general results for flow within the blade row, relations to two-dimensional cascade theory, and finite blade and wake effects. Numerical results are presented, giving attention to the problem of wakeless flow and of wake flow. Expressions for wake functions are given in an appendix. The lifting line velocity potential employed by Namba (1972) is used as a starting point in the discussion of the lifting surface theory. A study of subsonic conditions is supplemented by an investigation of a transonic compresso, taking into account the general three-dimensional solution, induced velocities, and the acoustic pressure field.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA Journal; 12; Oct. 197
    Format: text
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