Showing papers by "Langley Research Center published in 1970"
01 Dec 1970
TL;DR: In this article, the authors compared results of reentry plasma diagnostic experiment at 25,000 ft/sec with flow-field values at four locations on spacecraft, and found that the results of the experiment showed promising results.
Abstract: Comparing results of reentry plasma diagnostic experiment at 25,000 ft/sec with flow-field values at four locations on spacecraft
100Â citations
TL;DR: In this paper, the acoustic characteristics of high subsonic model cold jet using imaging technique and measurements of energy flux of flow, calculating energy flux from flowfield measurements are presented.
Abstract: Acoustic characteristics of high subsonic model cold jet using imaging technique and measurements of energy flux of flow, calculating energy flux from flowfield measurements
61Â citations
TL;DR: Free stream disturbances influence on hypersonic boundary layer transition Reynolds number in heated and unheated flows as discussed by the authors, which is a measure of the influence of free stream disturbances on the transition of the boundary layer.
Abstract: Free stream disturbances influence on hypersonic boundary layer transition Reynolds number in heated and unheated flows
48Â citations
01 Sep 1970
47Â citations
01 Jul 1970
44Â citations
TL;DR: In this paper, film cooling effectiveness in hypersonic turbulent flow from downstream surface equilibrium temperature measurement is investigated, and the results show that film cooling is effective in reducing turbulent flow.
Abstract: Film cooling effectiveness in hypersonic turbulent flow from downstream surface equilibrium temperature measurement
43Â citations
01 Dec 1970
TL;DR: Integrating matrix method for determining natural lateral vibration data on rotating twisted propeller blade is proposed in this article for determining the lateral vibration of a propeller with respect to a single propeller.
Abstract: Integrating matrix method for determining natural lateral vibration data on rotating twisted propeller blade
40Â citations
TL;DR: The results of a preliminary analytical and experimental study of trim drag characteristics at maneuvering lift coefficients have been summarized in this article, where it is shown that tail load required to minimize trim drag is highly dependent on the wingbody drag-due-to-lift characteristics with examples presented for both the full and zero leading-edge suction cases.
Abstract: The results of a preliminary analytical and experimental study of trim drag characteristics at maneuvering lift coefficients have been summarized. The study included aft-tail configurations at subsonic and supersonic speeds and canard configurations at subsonic speeds. It is shown that the tail load required to minimize trim drag is highly dependent on the wingbody drag-due-to-lift characteristics with examples presented for both the full and zero leading-edge suction cases. For the high drag case (corresponding to zero leading-edge suction), which tends to be typical at high maneuvering lift coefficients and high speeds, rather large uploads on the tail are required to reduce the trim drag problem. The analytical predictions of trim drag characteristics compare well with the experiment for the aft-tail configuration. At supersonic speeds, reductions in down tail load required to trim, obtained by increasing tail volume and thereby allowing a favorable rebalancing of the aircraft, result in relatively large reductions in trim drag for aft-tail configurations. At subsonic speeds, the experimental studies for the canard configuration exhibit considerably higher trim drag than the analytical prediction as a result of canard stall.
40Â citations
TL;DR: Hypersonic corner flow in He investigated by heat transfer, surface pressure, pitot surveys, oil and electron beam flow measurements was investigated by as discussed by the authors, and was shown to be stable with respect to temperature and pressure.
Abstract: Hypersonic corner flow in He investigated by heat transfer, surface pressure, pitot surveys, oil and electron beam flow measurements
36Â citations
01 Jun 1970
TL;DR: In this paper, wind tunnel analysis of static longitudinal and lateral characteristics of light single engine low wing airplane was performed in the presence of a single engine and a single winged aircraft.
Abstract: Wind tunnel investigation of static longitudinal and lateral characteristics of light single engine low wing airplane
34Â citations
01 Sep 1970
TL;DR: In this paper, the effects of pointed nose on spin characteristics of fighter aircraft model and correlation of free flight test results with theoretical data were investigated, and the results showed that the pointed nose effect was positively correlated with the performance of the model.
Abstract: Effects of pointed nose on spin characteristics of fighter aircraft model and correlation of free flight test results with theoretical data
01 Feb 1970
TL;DR: Radio blackout alleviation and plasma diagnostic results from 25000 foot per second blunt body reentry are presented.
Abstract: Radio blackout alleviation and plasma diagnostic results from 25000 foot per second blunt body reentry
01 May 1970
TL;DR: Transonic wind tunnel tests to determine wake effect of tip-mounted fan-jet engine on reducing tip vorticity of unswept symmetrical panel were conducted in this article, and the results showed that the fan-joint engine reduced the tip-vorticity significantly.
Abstract: Transonic wind tunnel tests to determine wake effect of tip-mounted fan-jet engine on reducing tip vorticity of unswept symmetrical panel
TL;DR: The design of a practical controller for a plant representative of a telescope primary mirror for an orbiting astronomical observatory is presented and a quadratic performance index which incorporates a measure of image quality permits determination of the trade-off between the number of actuators and optical purity.
TL;DR: The method of combining wedge diffraction solutions for the analysis of an axial TEM-mode slot is extended here for an arbitrary aperture antenna in a finite size ground plane as mentioned in this paper, where the boundary value solution considers the pattern component when the aperture is in an infinite ground plane, and the diffraction solution (secondary pattern) considers the contribution to the pattern from the edges of the finite ground plane.
Abstract: The method of combining wedge diffraction solutions for the analysis of an axial TEM-mode slot is extended here for an arbitrary aperture antenna in a finite size ground plane. The new approach, however, considers superposition of boundary-value and wedge-diffraction solutions on the same antenna. The boundary-value solution (primary pattern) considers the pattern component when the aperture is in an infinite ground plane, and the diffraction solution (secondary pattern) considers the contribution to the pattern from the edges of the finite ground plane.
01 Apr 1970
TL;DR: A survey of velocity profile data from turbulent boundary layers with zero and slightly favorable pressure gradients has been made as mentioned in this paper, where data obtained at Mach numbers up to about 20 have been included in the survey.
Abstract: MACH NUMBER INATURBULENTBOUNDARYLAYER By Charles B. Johnson and Dennis M. Bushnell Langley Research Center SUMMARY A survey of velocity-profile data from turbulent boundary layers with zero and slightly favorable pressure gradients has been made. Data obtained at Mach numbers up to about 20 have been included in the survey. The profile shapes were characterized according to the 1/N-power
01 Nov 1970
TL;DR: In this article, the authors compared aircraft and surface vehicle stopping performance under varying runway conditions, and found that aircraft stopping performance was significantly worse than surface vehicles stopping under varying ground conditions.
Abstract: Comparison of aircraft and surface vehicle stopping performance under varying runway conditions
01 Jan 1970
TL;DR: Mathematical analysis of Reynolds analogy for turbulent heat transfer, skin friction, and boundary layer flow in adiabatic conditions is presented in this paper, where the boundary layer is modeled as a Reynolds analogy.
Abstract: Mathematical analysis of Reynolds analogy for turbulent heat transfer, skin friction, and boundary layer flow in adiabatic conditions
01 Sep 1970
TL;DR: In this article, the experimental results from a ground-test program are presented for a carbon-phenolic heat-shield material designated Narmco 4028, which was used in supersonic streams of air, nitrogen, and air-nitrogen mixtures at model stagnation pressures from 0.07 to 11 atmospheres (1 atmosphere equals 101.325 kN/m2).
Abstract: : The experimental results from a ground-test program are presented for a carbon-phenolic heat-shield material designated Narmco 4028. The tests were conducted in supersonic streams of air, nitrogen, and air-nitrogen mixtures at model stagnation pressures from 0.07 to 11 atmospheres (1 atmosphere equals 101.325 kN/m2) and stagnation enthalpies from 1100 to 11000 Btu/lbm (2.55 to 25.50 MJ/kg). Mechanical char removal of the material did not occur in the nitrogen tests but did occur in air and air-nitrogen mixtures at pressures as low as 2.4 atmospheres depending upon the oxygen mass fraction in the stream. The experimental results were compared with predictions from an ablation computer program.
TL;DR: In this article, an extension of Oliner's theory is used to predict the impedance of slots with dielectric coatings, and theoretical curves are presented which show the change in impedance as a function of dielectrics constant, dielectors losses, and dielectoric thickness.
Abstract: An extension of Oliner's theory is used to predict the impedance of slots with dielectric coatings. Theoretical curves are presented which show the change in impedance as a function of dielectric constant, dielectric losses, and dielectric thickness. The effect of a dielectric or plasma upon the resonant frequency is also included. The agreement with experimental dielectric-covered slot data justifies the extension of Oliner's theory.
TL;DR: In this paper, electron concentration profiles in the blunt nose vehicle shock layer during atmospheric near orbital entry at high altitudes, using finite rate chemistry were obtained using finite-rate chemistry.
Abstract: Electron concentration profiles in blunt nose vehicle shock layer during atmospheric near orbital entry at high altitudes, using finite rate chemistry
TL;DR: Tests consisting of one- and two-axis closed-loop tracking tasks, with and without motion, have been made to define some areas where motion cues are beneficial.
Abstract: Tests consisting of one- and two-axis closed-loop tracking tasks, with and without motion, have been made to define some areas where motion cues are beneficial. Tests were made with reduced scaling on the motion input to investigate the minimum requirements of motion cues in those tests where motion was found to be of assistance. For the set of conditions tested, little or no difference in the measurement criteria was observed in the single-axis motion/no motion runs. Similar results were obtained when comparing two single-axis tests with different pitch orientation. The two-axis tests, which consisted of pitch and yaw and pitch and roll, did, however, produce a difference in the error measurements in the motion/no motion comparison. A decrease in normalized tracking error and an increase in closed-loop system frequency were observed when motion was added. Tests were also run, in pitch and yaw only, in which the scale of the motion input was reduced. These tests were performed by the subject in sequence starting with no motion all the way to full motion and back down to no motion. Each motion scale condition (none, 1/16, ?, ?, ?, and full) constituted a test. The normalized tracking error remained constant for full, ?, and ? motion scaling, but increased with a further reduction in motion scaling.
TL;DR: In this paper, the opening distance and inflation time prediction for parachutes deployed supersonically based on subsonic performance were predicted for a single-person supersonic parachute.
Abstract: Opening distance and inflation time prediction for parachutes deployed supersonically based on subsonic performance
01 Jan 1970
TL;DR: In this paper, electron density profiles for three RAM C hypersonic reentries were determined using a probe determinant for electron density profile for each of the three RAMC-C reentry phases.
Abstract: Electrostatic probe determinations of electron density profiles for three RAM C hypersonic reentries
TL;DR: Inflatable decelerator for planetary atmospheric entry, discussed mission applications and wind tunnel models performance as discussed by the authors, and attached Inflatable Decelerator was used for atmospheric entry.
Abstract: Attached Inflatable Decelerator for planetary atmospheric entry, discussing mission applications and wind tunnel models performance
01 Jan 1970
TL;DR: In this paper, a model for investigating radiation of noise generated by rotating blades in circular ducts is proposed, where the model is based on the model of the model proposed in this paper.
Abstract: Mathematical model for investigating radiation of noise generated by rotating blades in circular duct
01 Mar 1970
01 Jan 1970
TL;DR: A review of procedures and a summary of recent results on the mass and gravitational field of the moon is presented in this paper, where the relative and absolute precisions of the solutions in fitting the data are illustrated by residual plots and other considerations.
Abstract: This paper presents a review of procedures and a summary of recent results on the mass and gravitational field of the moon. Gravitational field solutions as represented by spherical harmonic expansions of the potential through various degrees and order are available, and typical solutions obtained by the different procedures are presented. The relative and absolute precisions of the solutions in fitting the data are illustrated by residual plots and other considerations. Lunar surface elevation plots, based on the gravitational coefficients (assuming homogeneity), illustrate the distribution and magnitude of mass anomalies over the lunar sphere. For a l3th-order field, the contour plots show considerable correlation with published mascon results in regions where such results are available. The recently obtained gravitational field results are applied to determination of the moments of inertia of the moon, which correspond closely to overall homogeneous density distribution in the moon, and to determination of other properties related to mass distribution.
01 Dec 1970
TL;DR: In this paper, the longitudinal aerodynamic characteristics of four engine externally blowing jet-flap STOL aircraft were determined for a single-engine aircraft with a single engine and a single jet flap.
Abstract: Determination of low speed longitudinal aerodynamic characteristics of four engine externally blowing jet-flap STOL aircraft