The Flow of a Compressible Fluid Past a Curved Surface (open access)

The Flow of a Compressible Fluid Past a Curved Surface

"An iteration method is employed to obtain the flow of a compressible fluid past a curved surface. The first approximation which leads to the Prandtl-Glauert rule, is based on the assumption that the flow differs but little from a pure translation. The iteration process then consists in improving this first approximation in order that it will apply to a flow differing from pure translatory motion to a greater degree. The method fails when the Mach number of the undisturbed stream reaches unity but permits a transition from subsonic to supersonic conditions without the appearance of a compression shock" (p. 305).
Date: September 13, 1943
Creator: Kaplan, Carl
System: The UNT Digital Library
Combustion efficiencies in hydrocarbon-air systems at reduced pressures (open access)

Combustion efficiencies in hydrocarbon-air systems at reduced pressures

Report presenting results obtained with quiescent fuel-air mixtures and with small diffusion flames, which indicate that combustion efficiencies close to 100 percent were obtained at pressure much lower than those found in turbojet combustors at altitudes of 60,000 feet.
Date: September 13, 1950
Creator: Hibbard, Robert R.; Drell, Isadore L.; Metzler, Allen J. & Spakowski, Adolph E.
System: The UNT Digital Library
Investigation of effects of inlet-air velocity distortion on performance of turbojet engine (open access)

Investigation of effects of inlet-air velocity distortion on performance of turbojet engine

To determine effect of nonuniform inlet-air velocities, a full scale, axial-flow turbojet engine was investigated in Lewis altitude wind tunnel at altitudes from 20,000 to 50,000 feet, 0.21 flight Mach number and corrected engine speeds from 77.3 percent of rated speed to rated speed. Total-pressure variations as large as 103 pounds per square foot in radial direction and 90 pounds per square foot in circumferential direction at 30,000 feet were obtained. With the distortions investigated, net thrust varied between 0.95 and 1.03 of the thrust with uniform inlet-air distribution. Similarly the ratio of specific fuel consumption varied from 1.00 to 1.04. Within the arrange of this investigation the effects of nonuniform inlet velocity were not serious for the engine investigated.
Date: September 13, 1950
Creator: Conrad, E. William & Sobolewski, Adam E.
System: The UNT Digital Library
Preliminary investigation of porous walls as a means of reducing tunnel boundary effects at low-supersonic Mach numbers (open access)

Preliminary investigation of porous walls as a means of reducing tunnel boundary effects at low-supersonic Mach numbers

Report presenting the use of porous-walled tunnels at supersonic Mach numbers as a means of avoiding reflection of a stream disturbance extending to the walls. Results from analysis and an experiment with a 4 degree wedge at a Mach number of 1.2 are provided.
Date: September 13, 1950
Creator: Nelson, William J. & Bloetscher, Frederick
System: The UNT Digital Library
Force and pressure characteristics for a series of nose inlets at Mach numbers from 1.59 to 1.99 5: analysis and comparison on basis of ram-jet aircraft range and operational characteristics (open access)

Force and pressure characteristics for a series of nose inlets at Mach numbers from 1.59 to 1.99 5: analysis and comparison on basis of ram-jet aircraft range and operational characteristics

Performance of four experimentally investigated axially symmetric spike-type nose inlets is compared on basis of ram-jet-engine aircraft range and operational problems. At design conditions, calculated peak engine efficiencies varied 25 percent from the highest value which indicates importance of inlet design. Calculations for a typical supersonic aircraft indicate possible increase in range if engine is flown at moderate angle of attack and result in engine lift utilized. For engines with fixed exhaust nozzle, propulsive thrust increases with increasing heat addition in subcritical flow region in spite of increasing additive drag. For the perforated inlet there is a range of increasing total-temperature ratios in subcritical flow region that does not yield an increase in propulsive thrust. Effects of inlet characteristics on speed stability of a typical aircraft for three types of fuel control is discussed.
Date: September 13, 1951
Creator: Howard, E.; Luidens, R. W. & Allen, J. L.
System: The UNT Digital Library
Lift, drag, and pitching moment of low-aspect-ratio wings at subsonic and supersonic speeds : plane triangular wing of aspect ratio 3 with NACA 0003-63 section (open access)

Lift, drag, and pitching moment of low-aspect-ratio wings at subsonic and supersonic speeds : plane triangular wing of aspect ratio 3 with NACA 0003-63 section

Report presenting a wing-body combination with a plane triangular wing of aspect ratio 3 and NACA 0003-63 sections in streamwise planes at subsonic and supersonic Mach numbers. Lift, drag, and pitching moment are presented for a range of Mach and Reynolds numbers.
Date: September 13, 1951
Creator: Heitmeyer, John C.
System: The UNT Digital Library
A Relation of Wind Shear and Insolation to the Turbulence Encountered by an Airplane in Clear-Air Flight at Low Altitudes (open access)

A Relation of Wind Shear and Insolation to the Turbulence Encountered by an Airplane in Clear-Air Flight at Low Altitudes

Memorandum presenting the observed gust experience of an airplane and information on the associated meteorological conditions to obtain a simple empirical relation for estimating the intensity of turbulence in the earth's friction layer. The relation does not discriminate between differences in turbulence intensity resulting from variations of flight altitude or diurnal variations of turbulence.
Date: September 13, 1951
Creator: Thompson, James K.
System: The UNT Digital Library
Wind-tunnel investigation at low speed of the yawing stability derivatives of a 1/10-scale model of the Douglas A4D-1 airplane: TED No. NACA DE 389 (open access)

Wind-tunnel investigation at low speed of the yawing stability derivatives of a 1/10-scale model of the Douglas A4D-1 airplane: TED No. NACA DE 389

Report presenting an experimental investigation to determine the low-speed yawing stability derivatives of a model of the Douglas A4D-1 airplane. The model was tested in clean and landing configurations with horizontal and vertical tails on and off. Results are provided without analysis.
Date: September 13, 1954
Creator: Wolhart, Walter D. & Fletcher, H. S.
System: The UNT Digital Library