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The Propeller and Cooling-Air-Flow Characteristics of a Twin-Engine Airplane Model Equipped With NACA D(Sub S)-Type Cowlings and With Propellers of NACA 16-Series Airfoil Sections

Description: Report presenting an investigation in the 19-foot pressure tunnel to determine the nacelle drag, the cowling-air flow, and the propeller characteristics of a model of a high-performance military airplane. The model is fitted with NACA D(sub S)-type engine cowlings and with propellers embodying NACA 16-series airfoil sections. Results regarding the propeller characteristics, drag and cowling-air flow with the propeller removed, the effect of propeller on flow through cowling, and the influence of cooling requirements on airplane performance are provided.
Date: September 1944
Creator: McHugh, James G. & Pepper, Edward
Partner: UNT Libraries Government Documents Department

Profile-Drag Coefficients of Conventional and Low-Drag Airfoils as Obtained in Flight

Description: "The results of flight investigations of the profile drag of several carefully finished conventional and low-drag airfoils are presented. The results indicated that in all cases lower profile-drag coefficients were obtained with the low-drag than with the conventional airfoils over the range of lift coefficient tested and that, for comparable conditions of lift coefficient and Reynolds number, the low-drag airfoils may have profile-drag coefficients which are at least 27 percent lower than the profile-drag coefficients of the conventional airfoils" (p.1).
Date: May 1944
Creator: Zalovcik, John A.
Partner: UNT Libraries Government Documents Department

On the Flow of a Compressible Fluid by the Hodography Method 1: Unification and Extension of Present-Day Results

Description: Report presenting elementary basic solutions of the equations of motion of a compressible fluid in the hodograph variables are developed and used to provide a basis for comparison in the form of velocity correction formulas, of corresponding compressible and incompressible flows.
Date: March 1944
Creator: Garrick, I. E. & Kaplan, Carl
Partner: UNT Libraries Government Documents Department

Determination of General Relations for the Behavior of Turbulent Boundary Layers

Description: Report presenting an analysis 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. Results indicate that the type of velocity distribution in the boundary layer could be expressed in terms of a single parameter.
Date: July 1943
Creator: von Doenhoff, Albert E. & Tetervin, Neal
Partner: UNT Libraries Government Documents Department

On the Flow of a Compressible Fluid by the Hodography Method 2: Fundamental Set of Particular Flow Solutions of the Chaplygin Differential Equation

Description: Report presenting the utilization of the differential equation of Chaplygin's jet problem to give a systematic development of particular solutions of the hodograph flow equations, which extends the treatment of Chaplygin into the supersonic range and completes the set of particular solutions. The solutions serve to place on a reasonable basis the use of velocity correction formulas for the comparison of incompressible and compressible flows.
Date: November 1944
Creator: Kaplan, Carl
Partner: UNT Libraries Government Documents Department

Notes on the Effect of Surface Distortions on the Drag and Critical Mach Number of Airfoils

Description: "The effect of two-dimensional bumps and surface waviness on the pressure distribution over airfoils is considered. It is shown that the results of the analysis may be useful in evaluating the effects of accidental or intended surface distortions on the drag and critical Mach number of airfoils" (p. 1).
Date: September 1943
Creator: Allen, H. Julian
Partner: UNT Libraries Government Documents Department

Experiments on Drag of Revolving Disks, Cylinders and Streamline Rods at High Speeds

Description: Report presenting an experimental investigation concerned primarily with the extension of test data on the drag of revolving disks, cylinders, and streamline rods to high Mach numbers and Reynolds numbers. The tests generally confirm earlier theories and add in some new results. One of the primary findings of interest is that skin friction does not depend on Mach number.
Date: June 1944
Creator: Theodorsen, Theodore & Regier, Arthur
Partner: UNT Libraries Government Documents Department

NACA Mach number indicator for use in high-speed tunnels

Description: Report presenting a description of a device for indicating stream Mach number in a high-speed tunnel. It consists of a mechanism for determining the pressure ratio that Mach number is a function of. The instrument is in service in the 8-foot high-speed tunnel and its accuracy has been found adequate for wind-tunnel requirements.
Date: July 1943
Creator: Smith, Norman F.
Partner: UNT Libraries Government Documents Department

Performance of an exhaust-gas "blowdown" turbine on a nine-cylinder radial engine

Description: Report presenting tests on an exhaust-gas turbine with four separate nozzle boxes each covering a 90 degree arc of the nozzle diaphragm and each connected to a pair of adjacent cylinders in a Pratt & Whitney R-1340-12 nine-cylinder radial engine. Results regarding the power output of the engine and turbine, effect of the turbine on engine power, turbine power output and speed characteristics, mean turbine efficiency, effect of the blowdown turbine on exhaust-gas temperature, and condition of the blowdown turbine after tests are provided.
Date: December 1944
Creator: Turner, L. Richard & Desmon, Leland G.
Partner: UNT Libraries Government Documents Department

A Concise Theoretical Method for Profile-Drag Calculation; Advance Report

Description: In this report a method is presented for the calculation of the profile drag of airfoil sections. The method requlres only a knowledge of the theoretical velocity distribution and can be applied readily once this dlstribution is ascertained. Comparison of calculated and experimental drag characteristics for several airfoils shows a satisfactory agreement. Sample calculatlons are included.
Date: February 1944
Creator: Nitzberg, Gerald E.
Partner: UNT Libraries Government Documents Department

The development and application of high-critical-speed nose inlets

Description: From Summary: "An analysis of the nose-inlet shapes developed in previous investigations to represent the optimum from the standpoint of critical speed has shown that marked similarity exists between the nondimensional profiles of inlets which have widely different proportions and critical speeds. With the nondimensional similarity of such profiles established, the large differences in the critical speeds of these nose inlets must be a function of their proportions. An investigation was undertaken in the Langley 8-foot high-speed tunnel to establish the effects of nose-inlet proportions on critical Mach number and to develop a rational method for the design of high-critical-speed nose inlets to meet desired requirements."
Date: July 1945
Creator: Baals, Donald D.; Smith, Norman F. & Wright, John B.
Partner: UNT Libraries Government Documents Department

NACA Investigation of a Jet-Propulsion System Applicable to Flight

Description: "Following a brief history of the NACA investigation of jet-propulsion, a discussion is given of the general investigation and analyses leading to the construction of the jet-propulsion ground-test mock-up. The results of burning experiments and of test measurements designed to allow quantitative flight-performance predictions of the system are presented and correlated with calculations. These calculations are then used to determine the performance of the system on the ground and in the air at various speeds and altitudes under various burning conditions. The application of the system to an experimental airplane is described and some performance predictions for this airplane are made" (p. 1).
Date: April 1944
Creator: Brown, Clinton E.
Partner: UNT Libraries Government Documents Department

Investigation of Flow in an Axially Symmetrical Heated Jet of Air

Description: The work done under this contract falls essentially into two parts: the first part was the design and construction of the equipment and the running of preliminary tests on the 3-inch jet, carried out by Mr. Carl Thiele in 1940; the second part consisting in the measurement in the 1-inch jet flow in an axially symmetrical heated jet of air.
Date: December 1943
Creator: Corrsin, Stanley
Partner: UNT Libraries Government Documents Department

A Method for the Rapid Estimation of Turbulent Boundary-Layer Thickness for Calculating Profile Drag

Description: "An analysis is developed that makes it possible to integrate von Kármán's boundary-layer momentum equation directly. For this purpose, the skin friction coefficient is expressed as a function of the Reynolds number based on the boundary-layer momentum thickness and the boundary-layer shape is assumed to be constant. The integrated equation permits the boundary-layer momentum thickness at the airfoil trailing edge to be rapidly determined for the estimation of airfoil profile-drag coefficients" (p .1).
Date: July 1944
Creator: Tetervin, Neal
Partner: UNT Libraries Government Documents Department

An Infrared Cloud Indicator 1: Analysis of Infrared-Radiation Exchange With Tables and Chart for Calibration of the Cloud Indicator

Description: Report presenting a description of an experimental model of a flight instrument that utilizes infrared radiations for detecting and indicating the location of clouds at night. A preliminary investigation is made of data in the scientific literature. A table and chart are developed that make it practical to determine the magnitude of the net exchange of radiation for any particular atmosphere of known composition and distribution of temperature.
Date: November 1945
Creator: Warfield, Calvin N. & Kenimer, Robert L.
Partner: UNT Libraries Government Documents Department

Theory and Application of Hot-Wire Instruments in the Investigation of Turbulent Boundary Layers

Description: Report presenting an account of the recent developments in hot-wire instruments for use in turbulent boundary layers to determine the magnitude of the several components of the turbulent velocity fluctuations together with the correlation between them and turbulent shearing stress.
Date: March 1946
Creator: Schubauer, G. B. & Klebanoff, P. S.
Partner: UNT Libraries Government Documents Department

Propeller Selection From Aerodynamic Considerations

Description: Report presenting a theoretical analysis of the performance of propellers extending to high values. Charts are presented that facilitate the selection of the most efficient propellers over a wide range of operating conditions.
Date: July 1942
Creator: Crigler, John L. & Talkin, Herbert W.
Partner: UNT Libraries Government Documents Department

An Additional Investigation of the High-Speed Lateral-Control Characteristics of Spoilers

Description: Report presenting an investigation of the characteristics of partial-span spoilers located at 0.75 of the chord on an NACA 66-series tapered wing, especially at high speeds. The effect of small spoiler projections was found to increase with an increase in speed until the critical Mach number was exceeded.
Date: June 1945
Creator: Laitone, Edmund V. & Summers, James L.
Partner: UNT Libraries Government Documents Department

Stalling Characteristics of the Supermarine Spitfire VA Airplane

Description: Report presenting an investigation of the stalling characteristics of the Supermarine Spitfire, which was made as part of the flying-qualities measurement of the airplane. The results are presented in the form of time histories of the motions and controls during stalls in various conditions of flight. Generally, the Spitfire possessed good stall warning in the form of buffeting and stall motions were not violent.
Date: September 1942
Creator: Vensel, J. R. & Phillips, W. H.
Partner: UNT Libraries Government Documents Department

Investigations on Laminar Boundary-Layer Stability and Transition on Curved Boundaries

Description: Report presenting an investigation of the transition of the boundary layer from the laminar to the turbulent region on a flat plate, on the concave and convex side of a plate with a 20-foot radius of curvature, and on the convex side of a plate with a 30-inch radius of curvature.
Date: May 1946
Creator: Liepmann, Hans W.
Partner: UNT Libraries Government Documents Department

Experimental Study of the Coating Formed on Nitrided-Steel Piston Rings During Operation in Nitrided-Steel Cylinders

Description: Report presenting a study of nitrided-steel piston rings in nitrided-steel cylinder barrels, which showed material of high reflectivity on their running faces. The structure of the material could not be resolved at a magnification of 1500 diameters. Results regarding the occurrence of coating, thickness of coating, height of coating above the nominal surface, chemical characteristics, physical characteristics, metallurgical change, and additional tests are provided.
Date: March 1944
Creator: Bobrowsky, A. R.; Kittel, J. Howard & Boegli, Charles P.
Partner: UNT Libraries Government Documents Department