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  Partner: UNT Libraries Government Documents Department
 Year: 1943
 Serial/Series Title: NACA Technical Reports
Aerodynamic and hydrodynamic tests of a family of models of flying hulls derived from a streamline body -- NACA model 84 series

Aerodynamic and hydrodynamic tests of a family of models of flying hulls derived from a streamline body -- NACA model 84 series

Date: January 1, 1943
Creator: Parkinson, John B
Description: A series of related forms of flying-boat hulls representing various degrees of compromise between aerodynamic and hydrodynamic requirements was tested in Langley Tank No. 1 and in the Langley 8-foot high-speed tunnel. The purpose of the investigation was to provide information regarding the penalties in water performance resulting from further aerodynamic refinement and, as a corollary, to provide information regarding the penalties in range or payload resulting from the retention of certain desirable hydrodynamic characteristics. The information should form a basis for over-all improvements in hull form.
Contributing Partner: UNT Libraries Government Documents Department
Analysis of heat and compressibility effects in internal flow systems and high-speed tests of a ram-jet system

Analysis of heat and compressibility effects in internal flow systems and high-speed tests of a ram-jet system

Date: January 1, 1943
Creator: Becker, John V
Description: An analysis has been made by the NACA of the effects of heat and compressibility in the flow through the internal systems of aircraft. Equations and charts are developed whereby the flow characteristics at key stations in a typical internal system may be readily obtained.
Contributing Partner: UNT Libraries Government Documents Department
Derivation of charts for determining the horizontal tail load variation with any elevator motion

Derivation of charts for determining the horizontal tail load variation with any elevator motion

Date: January 1, 1943
Creator: Pearson, Henry A
Description: The equations relating the wing and tail loads are derived for a unit elevator displacement. These equations are then converted into a nondimensional form and charts are given by which the wing- and tail-load-increment variation may be determined under dynamic conditions for any type of elevator motion and for various degrees of airplane stability. In order to illustrate the use of the charts, several examples are included in which the wing and tail loads are evaluated for a number of types of elevator motion. Methods are given for determining the necessary derivatives from results of wind-tunnel tests when such tests are available.
Contributing Partner: UNT Libraries Government Documents Department
Determination of general relations for the behavior of turbulent boundary layers

Determination of general relations for the behavior of turbulent boundary layers

Date: January 1, 1943
Creator: Von Doenhoff, Albert E
Description: An analysis has been made of a considerable amount of data for turbulent boundary layers along wings and bodies of various shapes in order to determine the fundamental variables that control the development of turbulent boundary layers. It was found that the type of velocity distribution in the boundary layer could be expressed in terms of a single parameter. This parameter was chosen as the ratio of the displacement thickness to the momentum thickness of the boundary layer. The variables that control the development of the turbulent boundary layer apparently are: (1) the ratio of the nondimensional pressure gradient, expressed in terms of the local dynamic pressure outside the boundary layer and boundary-layer thickness, to the local skin-friction coefficient and (2) the shape of the boundary layer. An empirical equation has been developed in terms of these variables that, when used with the momentum equation and the skin-friction relation, makes it possible to trace the development of the turbulent boundary layer to the separation point.
Contributing Partner: UNT Libraries Government Documents Department
The effect of mass distribution on the lateral stability and control characteristics of an airplane as determined by tests of a model in the free-flight tunnel

The effect of mass distribution on the lateral stability and control characteristics of an airplane as determined by tests of a model in the free-flight tunnel

Date: January 1, 1943
Creator: Campbell, John P
Description: The effects of mass distribution on lateral stability and control characteristics of an airplane have been determined by flight tests of a model in the NACA free-flight tunnel. In the investigation, the rolling and yawing moments of inertia were increased from normal values to values up to five times normal. For each moment-of-inertia condition, combinations of dihedral and vertical-tail area representing a variety of airplane configurations were tested. The results of the flight tests of the model were correlated with calculated stability and control characteristics and, in general, good agreement was obtained.
Contributing Partner: UNT Libraries Government Documents Department
Exhaust-stack nozzle area and shape for individual cylinder exhaust-gas jet-propulsion system

Exhaust-stack nozzle area and shape for individual cylinder exhaust-gas jet-propulsion system

Date: January 1, 1943
Creator: Pinkel, Benjamin
Description: This report presents the results of an investigation conducted on the effect of exhaust-stack nozzle area, shape, and length on engine power, jet thrust, and gain in net thrust (engine propeller plus jet). Single-cylinder engine data were obtained using three straight stacks 25, 44, and 108 inches in length; an S-shaped stack, a 90 degree bend, a 180 degree bend, and a short straight stack having a closed branch faired into it. Each stack was fitted with nozzles varying in exit area from 0.91 square inch to the unrestricted area of the stack of 4.20 square inches. The engine was generally operated over a range of engine speeds from 1300 to 2100 r.p.m, inlet-manifold pressures from 22 to 30 inches of mercury absolute, and a fuel-air ratio of 0.08. The loss in engine power, the jet thrust, and the gain in net thrust are correlated in terms of several simple parameters. An example is given for determining the optimum nozzle area and the overall net thrust.
Contributing Partner: UNT Libraries Government Documents Department
The flow of a compressible fluid past a curved surface

The flow of a compressible fluid past a curved surface

Date: January 1, 1943
Creator: Kaplan, Carl
Description: 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. The limiting value at which potential flow no longer exits is indicated by the apparent divergence of the power series representing the velocity of the fluid at the surface of the solid boundary.
Contributing Partner: UNT Libraries Government Documents Department
Identification of knock in NACA high-speed photographs of combustion in a spark-ignition engine

Identification of knock in NACA high-speed photographs of combustion in a spark-ignition engine

Date: January 1, 1943
Creator: Miller, Cearcy D
Description: Report presents the results of a study of combustion in a spark-ignition engine given in NACA Technical Reports 704 and 727. The present investigation was made with the NACA high-speed motion-picture camera, operating at 40,000 photographs a second, and with a cathode-ray oscillograph operating on a piezoelectric pick-up in the combustion chamber. Photographs are presented showing that the origin of knock is not necessarily in the end gas. The data obtained indicates that knock takes place only in a part of the cylinder charge which has been previously ignited either by autoignition or by the passage of the flame fronts but which has not burned to completion. Mottled regions in the high-speed Schlieren photographs are demonstrated to represent combustion regions.
Contributing Partner: UNT Libraries Government Documents Department
The induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

The induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

Date: January 1, 1943
Creator: Rothrock, Addison M
Description: Report presents the results of investigations conducted on a full-scale air-cooled aircraft-engine cylinder of 202-cubic inch displacement to determine the effects of internal cooling by water induction on the maximum permissible power and output of an internal-combustion engine. For a range of fuel-air and water-fuel ratios, the engine inlet pressure was increased until knock was detected aurally, the power was then decreased 7 percent holding the ratios constant. The data indicated that water was a very effective internal coolant, permitting large increases in engine power as limited by either knock or by cylinder temperatures.
Contributing Partner: UNT Libraries Government Documents Department
Jet-boundary corrections for reflection-plane models in rectangular wind tunnel

Jet-boundary corrections for reflection-plane models in rectangular wind tunnel

Date: January 1, 1943
Creator: Swanson, Robert S
Description: A detailed method for determining the jet-boundary corrections for reflection-plane models in rectangular wind tunnels is presented. The method includes the determination of the tunnel span local distribution and the derivation of equations for the corrections to the angle of attack, the lift and drag coefficients, and the pitching-, rolling-, yawing-, and hinge-moment coefficients. The principle effects of aerodynamic induction and of the boundary-induced curvature of the streamlines have been considered. An example is included to illustrate the method. Numerical values of the more important corrections for reflection-plane models in 7 by 10-foot closed wind tunnels are presented.
Contributing Partner: UNT Libraries Government Documents Department
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