You limited your search to:

  Partner: UNT Libraries Government Documents Department
 Serial/Series Title: NACA Technical Reports
 Collection: Technical Report Archive and Image Library
Attenuation in a shock tube due to unsteady-boundary-layer action

Attenuation in a shock tube due to unsteady-boundary-layer action

Date: January 1, 1957
Creator: Mirels, Harold
Description: A method is presented for obtaining the attenuation of a shock wave in a shock tube due to the unsteady boundary layer along the shock-tube walls. It is assumed that the boundary layer is thin relative to the tube diameter and induces one-dimensional longitudinal pressure waves whose strength is proportional to the vertical velocity at the edge of the boundary layer. The contributions of the various regions in a shock tube to shock attenuation are indicated. The method is shown to be in reasonably good agreement with existing experimental data.
Contributing Partner: UNT Libraries Government Documents Department
Automatic control systems satisfying certain general criterions on transient behavior

Automatic control systems satisfying certain general criterions on transient behavior

Date: January 1, 1952
Creator: Boksenbom, Aaron S & Hood, Richard
Description: An analytic method for the design of automatic controls is developed that starts from certain arbitrary criterions on the behavior of the controlled system and gives those physically realizable equations that the control system can follow in order to realize this behavior. The criterions used are developed in the form of certain time integrals. General results are shown for systems of second order and of any number of degrees of freedom. Detailed examples for several cases in the control of a turbojet engine are presented.
Contributing Partner: UNT Libraries Government Documents Department
Dynamics of a turbojet engine considered as a quasi-static system

Dynamics of a turbojet engine considered as a quasi-static system

Date: January 1, 1951
Creator: Otto, Edward W & Taylor, Burt L, III
Description: A determination of the dynamic characteristics of a typical turbojet engine with a centrifugal compressor, a sonic-flow turbine-nozzle diaphragm, and fixed area exhaust nozzle is presented. A generalized equation for transient behavior of the engine was developed; this equation was then verified by calculations using compressor and turbine performance charts extrapolated from equilibrium operating data and by experimental data obtained from an engine operated under transients in fuel flow. The results indicate that a linear differential equation for engine acceleration as a function of fuel flow and engine speed for operation near a steady-state operating condition can be written. The coefficients of this equation can be obtained either from actual transient data or, with a fair degree of accuracy, from the steady-state performance maps of the compressor and turbine, and can be corrected for altitude in the same manner that steady-state performance data are corrected.
Contributing Partner: UNT Libraries Government Documents Department
Dynamics of mechanical feedback-type hydraulic servomotors under inertia loads

Dynamics of mechanical feedback-type hydraulic servomotors under inertia loads

Date: January 1, 1953
Creator: Gold, Harold; Otto, Edward W & Ransom, Victor L
Description: An analysis of the dynamics of mechanical feedback-type hydraulic servomotors under inertia loads is developed and experimental verification is presented. The analysis, which is developed in terms of two physical parameters, yields direct expressions for the following dynamic responses: (1) the transient response to a step input and the maximum cylinder pressure during the transient and (2) the variation of amplitude attenuation and phase shift with the frequency of a sinusoidally varying input. The validity of the analysis is demonstrated by means of recorded transient and frequency responses obtained on two servomotors. The calculated responses are in close agreement with the measured responses. The relations presented are readily applicable to the design as well as to the analysis of hydraulic servomotors.
Contributing Partner: UNT Libraries Government Documents Department
Cloud-droplet ingestion in engine inlets with inlet velocity ratios of 1.0 and 0.7

Cloud-droplet ingestion in engine inlets with inlet velocity ratios of 1.0 and 0.7

Date: January 1, 1957
Creator: Brun, Rinaldo J
Description: The paths of cloud droplets into two engine inlets have been calculated for a wide range of meteorological and flight conditions. The amount of water in droplet form ingested by the inlets and the amount and distribution of water impinging on the inlet walls are obtained from these droplet-trajectory calculations. In both types of inlet, a prolate ellipsoid of revolution represents either part or all of the forebody at the center of an annular inlet to an engine. The configurations can also represent a fuselage of an airplane with side ram-scoop inlets. The studies were made at an angle of attack of 0 degree. The principal difference between the two inlets studied is that the inlet-air velocity of one is 0.7 that of the other. The studies of the two velocity ratios lead to some important general concepts of water ingestion in inlets.
Contributing Partner: UNT Libraries Government Documents Department
Attainable circulation about airfoils in cascade

Attainable circulation about airfoils in cascade

Date: January 1, 1950
Creator: Goldstein, Arthur W & Mager, Artur
Description: From consideration of available information on boundary-layer behavior, a relation among profile thickness, maximum surface velocity, Reynolds number, velocity diagram, and solidity is established for a cascade of airfoils immersed in a two-dimensional incompressible fluid flow. Several cascades are computed to show the effect of various cascade design parameters on minimum required cascade solidity. Comparisons with experimentally determined blade performance show that the derived blade loadings are equal or higher for moderate flow deceleration and somewhat lower for large deceleration. Blades with completely laminar flow appear practical for impulse or reaction blading.
Contributing Partner: UNT Libraries Government Documents Department
The effect of increased cooling surface on performance of aircraft-engine cylinders as shown by tests of the NACA cylinder

The effect of increased cooling surface on performance of aircraft-engine cylinders as shown by tests of the NACA cylinder

Date: January 1, 1944
Creator: Schey, Oscar W; Rollin, Verne G & Ellerbrock, Herman H , Jr
Description: A method of constructing fins of nearly optimum proportions has been developed by the NACA to the point where a cylinder has been manufactured and tested. Data were obtained on cylinder temperature for a wide range of inlet-manifold pressures, engine speeds, and cooling-pressure differences.
Contributing Partner: UNT Libraries Government Documents Department
Effect of initial mixture temperature on flame speed of methane-air, propane-air, and ethylene-air mixtures

Effect of initial mixture temperature on flame speed of methane-air, propane-air, and ethylene-air mixtures

Date: January 1, 1952
Creator: Dugger, Gordon L
Description: Flame speeds based on the outer edge of the shadow cast by the laminar Bunsen cone were determined as functions of composition for methane-air mixtures at initial mixture temperatures ranging from -132 degrees to 342 degrees c and for propane-air and ethylene-air mixtures at initial mixture temperatures ranging from -73 degrees to 344 degrees c. The data showed that maximum flame speed increased with temperature at an increasing rate. The percentage change in flame speed with change in initial temperature for the three fuels followed the decreasing order, methane, propane, and ethylene. Empirical equations were determined for maximum flame speed as a function of initial temperature over the temperature range covered for each fuel. The observed effect of temperature on flame speed for each of the fuels was reasonably well predicted by either the thermal theory as presented by Semenov or the square-root law of Tanford and Pease.
Contributing Partner: UNT Libraries Government Documents Department
Calculations of economy of 18-cylinder radial aircraft engine with exhaust-gas turbine geared to the crankshaft

Calculations of economy of 18-cylinder radial aircraft engine with exhaust-gas turbine geared to the crankshaft

Date: January 1, 1945
Creator: Hannum, Richard W & Zimmerman, Richard H
Description: Calculations based on dynamometer test-stand data obtained on an 18-cylinder radial engine were made to determine the improvement in fuel consumption that can be obtained at various altitudes by gearing an exhaust-gas turbine to the engine crankshaft in order to increase the engine-shaft work.
Contributing Partner: UNT Libraries Government Documents Department
Determination of stresses in gas-turbine disks subjected to plastic flow and creep

Determination of stresses in gas-turbine disks subjected to plastic flow and creep

Date: January 1, 1948
Creator: Millenson, M B & Manson, S S
Description: A finite-difference method previously presented for computing elastic stresses in rotating disks is extended to include the computation of the disk stresses when plastic flow and creep are considered. A finite-difference method is employed to eliminate numerical integration and to permit nontechnical personnel to make the calculations with a minimum of engineering supervision. Illustrative examples are included to facilitate explanation of the procedure by carrying out the computations on a typical gas-turbine disk through a complete running cycle. The results of the numerical examples presented indicate that plastic flow markedly alters the elastic-stress distribution.
Contributing Partner: UNT Libraries Government Documents Department