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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

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

Flight Investigation of Boundary-Layer and Profile-Drag Characteristics of Smooth Wing Sections of a P-47D Airplane

Description: Report presenting a flight investigation made of boundary-layer and profile-drag characteristics of smooth wing sections of a P-47D airplane. Measurements were made at three stations on the wing: boundary-layer measurements, pressure-distribution measurements, and wake surveys. The results indicated that a minimum profile-drag coefficient of 0.0062 for the smooth section at 63 percent semispan was obtained.
Date: October 1945
Creator: Zalovcik, John A.
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

Flight Investigation at High Speeds of Profile Drag of Wing of a P-47d Airplane Having Production Surfaces Covered With Camouflage Paint

Description: Report presenting a flight investigation made at high speeds to determine the profile drag of a P-47D airplane wing with production surfaces covered with camouflage paint. The results indicated that a minimum profile-drag coefficient of 0.0097 was attained for lift coefficients from 0.16 to 0.25 at Mach numbers less than 0.67.
Date: March 1946
Creator: Zalovcik, John A. & Daum, Fred L.
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

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

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

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

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

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

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

Flight Investigation of Boundary-Layer Transition and Profile Drag of an Experimental Low-Drag Wing Installed on a Figher-Type Airplane

Description: Report presenting a boundary-layer-transition and profile-drag investigation conducted on an experimental low-drag wing installed on a P-47 airplane designated the XP-47F. Measurements were made at a section outside the propeller slipstream with smooth and with standard camouflage surfaces and on the upper surface of a section in the propeller slipstream with the surface smoothed. Results regarding the right wing section outside the slipstream and left wing section in the propeller slipstream are provided.
Date: April 1945
Creator: Zalovcik, John A. & Skoog, Richard B.
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

Effects of Specific Types of Surface Roughness on Boundary-Layer Transition

Description: Report presenting tests conducted with two typical low-drag airfoils of 90-inch chord to determine the effects of surface projections, grooves, and sanding scratches on boundary-layer transition. Data were obtained for projections of various sizes and chordwise locations on both low-drag airfoils.
Date: February 1946
Creator: Loftin, Laurence K., Jr.
Partner: UNT Libraries Government Documents Department

Effects of Simulated Ice Formation on the Aerodynamic Characteristics of an Airfoil

Description: Report presenting an investigation of the size and distribution of ice particles on the wings of aircraft and how they affect the aerodynamic characteristics. A simulated ice formation was generated from survey information received from aircraft pilots and was tested to determine the impact on the lift characteristics.
Date: May 1938
Creator: Gulick, Beverly G.
Partner: UNT Libraries Government Documents Department

Effects on Low-Speed Spray Characteristics of Various Modifications to a Powered Model of the Boeing XPBB-1 Flying Boat

Description: Report presenting tests of a powered model of the Boeing XPBB-1 flying boat in order to observe the effects of trim and powered propellers, of lengths of forebody and afterbody, and of various spray strips on the low-speed spray characteristics. The effects of powering the propellers were to lower the trim and to pick up spray that would not strike the propeller disks when the propellers were windmilling. Results regarding the effects of trim and powered propellers, effect of length of forebody and afterbody, effect of angle of dead rise, and effect of various spray strips are provided.
Date: June 1945
Creator: King, Douglas A. & Mas, Newton A.
Partner: UNT Libraries Government Documents Department