Review of Flight Tests of NACA C and D Cowlings on the XP-42 Airplane (open access)

Review of Flight Tests of NACA C and D Cowlings on the XP-42 Airplane

"Results of flight tests of the performance and cooling characteristics of three NACA D cowlings and of a conventional NACA D cowling on the XP-42 airplane are summarized and compared. The D cowling is, in general, characterized by the use of an annular inlet and diffuser section for the engine-cooling air. The D cowlings tested were a long-nose high-inlet-velocity cowling, a short-nose high-inlet-velocity cowling, and a short-nose low inlet-velocity cowling" (p. 371).
Date: April 20, 1943
Creator: Johnston, J. Ford
System: The UNT Digital Library
Determination of general relations for the behavior of turbulent boundary layers (open access)

Determination of general relations for the behavior of turbulent boundary layers

From Summary: "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."
Date: April 13, 1943
Creator: von Doenhoff, Albert E. & Tetervin, Neal
System: The UNT Digital Library
Jet-boundary corrections for reflection-plane models in rectangular wind tunnels (open access)

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

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.
Date: April 13, 1943
Creator: Swanson, Robert S. & Toll, Thomas A.
System: The UNT Digital Library
Formulas for propellers in yaw and charts of the side-force derivative (open access)

Formulas for propellers in yaw and charts of the side-force derivative

General formulas are given for propellers for the rate of change of side-force coefficient with angle of yaw and for the rate of change of pitching-moment coefficient with angle of yaw. Charts of the side-force derivative are given for two propellers of different plan form. The charts cover solidities of two to six blades and single and dual rotation. The blade angle ranges from 15 degrees or 20 degrees to 60 degrees.
Date: April 7, 1943
Creator: Ribner, Herbert S.
System: The UNT Digital Library
Analysis of wind-tunnel stability and control tests in terms of flying qualities of full-scale airplanes (open access)

Analysis of wind-tunnel stability and control tests in terms of flying qualities of full-scale airplanes

From Introduction: "The purpose of this paper is to outline a suggested form of presentation of the results of a stability and control investigation in terms of flying qualities as defined in reference 1 and to systematize and review briefly the analytical work required for this type of presentation. No effort is made to specify definite test procedures."
Date: April 1, 1943
Creator: Kayten, Gerald G.
System: The UNT Digital Library
Effect of Varying Percentages of Exhaust Gas on Engine Performance (open access)

Effect of Varying Percentages of Exhaust Gas on Engine Performance

"These tests were run to determine the effect that mixing engine exhaust gas with engine intake air has on fuel knock limit, specific fuel consumption, and air consumption." Information about the effect on pressure, air consumption, and fuel consumption is detailed.
Date: April 1943
Creator: Sanders, Newell D. & Barnett, Henry C.
System: The UNT Digital Library
Effect of Wing Leading-Edge Slots on the Spin and Recovery Characteristics of Airplanes (open access)

Effect of Wing Leading-Edge Slots on the Spin and Recovery Characteristics of Airplanes

Report presenting an investigation in the NACA 15-foot free-spinning tunnel to determine the effect of wing leading-edge slots on spin and recovery characteristics. The results indicate that recovery will generally be slower with the slots open than with them closed and the spin will be flatter and at a lower rate of descent.
Date: April 1943
Creator: Neihouse, Anshal I. & Pitkin, Marvin
System: The UNT Digital Library
Effects of a Typical Nacelle on the Characteristics of a Thick Low-Drag Airfoil Critically Affected by Leading-Edge Roughness (open access)

Effects of a Typical Nacelle on the Characteristics of a Thick Low-Drag Airfoil Critically Affected by Leading-Edge Roughness

Report presenting testing to study the effects of a typical nacelle on the characteristics of a thick low-drag airfoil that was shown to be subject to separation difficulties due to leading edge roughness. This testing confirmed the results of previous tests which indicated that the airfoil was unconservative with respect to separation difficulties. Results regarding the internal-flow measurements and corresponding drag increments, external drag, leading-edge roughness and nacelle combination, and section lift comparisons are provided.
Date: April 1943
Creator: Ellis, Macon C., Jr.
System: The UNT Digital Library
Experimental Investigation of a Model of a Two-Stage Turboblower (open access)

Experimental Investigation of a Model of a Two-Stage Turboblower

"In the present paper an investigation is made of two stages of a multistage turboblower having a vaneless diffuser behind the impeller and guide vanes at the inlet to the nest stage. The method employed was that of investigating the performance of the successive elements of the blower (the impeller, vaneless diffuser, ets.) whereby the kinematics of the flow through the blower could be followed and the pressure at the different points computed. The character of the flow and the physical significance of the loss coefficients could thereby be determined so as to secure the best agreement of the computed with the actual performance of the blower" (p. 1).
Date: April 1943
Creator: Dovjik, S. & Polikovsky, W.
System: The UNT Digital Library
Flight Tests of a Glider Model Towed by Twin Parallel Towlines (open access)

Flight Tests of a Glider Model Towed by Twin Parallel Towlines

"The stability characteristics of a glider towed by twin parallel towlines have been studied in the NACA free-flight tunnel. A preliminary theoretical analysis of the stability of a glider restrained from yawing was followed by an experimental investigation of the stability of a model towed from fixed tunnel points in such a way as to simulate tow in level flight. The results of the tests confirm the theoretical analysis and indicate that a pilotless, stable, towed-glider system is possible when twin parallel towcables are used" (p. 1).
Date: April 1943
Creator: Pitkin, Marvin & McKinney, Marion O., Jr.
System: The UNT Digital Library
Flying Qualities and Stalling Characteristics of North American XP-51 Airplane (open access)

Flying Qualities and Stalling Characteristics of North American XP-51 Airplane

Report presenting a flight investigation of the flying qualities and stalling characteristics of a North American XP-51 airplane. The short-period longitudinal oscillation disappeared within one cycle in all conditions tested. Requirements for satisfactory stalling characteristics were met in all respects except for stall warning.
Date: April 1943
Creator: White, Maurice D.; Hoover, Herbert H. & Garris, Howard W.
System: The UNT Digital Library
Free-Flight-Tunnel Investigation of the Effect of the Fuselage Length and the Aspect Ratio and Size of the Vertical Tail on Lateral Stability and Control (open access)

Free-Flight-Tunnel Investigation of the Effect of the Fuselage Length and the Aspect Ratio and Size of the Vertical Tail on Lateral Stability and Control

Report presenting tests in the free-flight tunnel to determine the effect of the fuselage length and the aspect ratio and size of the vertical tail on lateral stability and control. Fuselages of two different lengths and various vertical tail surfaces were used on a powered model in the investigation. Results regarding the test conditions, flight tests, and force tests are provided.
Date: April 1943
Creator: Shortal, Joseph A. & Draper, John W.
System: The UNT Digital Library
Heat Transfer of Airfoils and Plates (open access)

Heat Transfer of Airfoils and Plates

"The few available test data on the heat dissipation of wholly or partly heated airfoil models are compared with the corresponding data for the flat plate as obtained by an extension of Prandtl's momentum theory, with differentiation between laminar and turbulent boundary layer and transitional region between both, the extent and appearance of which depend upon certain critical factors. The satisfactory agreement obtained justifies far-reaching conclusions in respect to other profile forms and arrangements of heated surface areas. The temperature relationship of the material quantities in its effect on the heat dissipation is discussed as far as is possible at the present state of research, and it is shown that the profile drag of heated wing surfaces can increase or decrease with the temperature increase depending upon the momentarily existent structure of the boundary layer" (p. 1).
Date: April 1943
Creator: Seibert, Otto
System: The UNT Digital Library
An investigation of aircraft heaters 11: measured and predicted performance of a slotted-fin exhaust gas and air heat exchanger (open access)

An investigation of aircraft heaters 11: measured and predicted performance of a slotted-fin exhaust gas and air heat exchanger

Report presenting the thermal and pressure drop performance data of a slotted-fin Stewart-Warner exhaust gas and ventilating air heat exchanger. Three different crossflow air shrouds were used in testing. The rate of heat transfer was about the same for each shroud, but the static pressure drops varied greatly.
Date: April 1943
Creator: Boelter, L. M. K.; Miller, M. A.; Sharp, W. H. & Morrin, E. H.
System: The UNT Digital Library
An Investigation of the Air Flow Around a Martin PBM-3 Flying Boat by Means of Tufts (open access)

An Investigation of the Air Flow Around a Martin PBM-3 Flying Boat by Means of Tufts

Report presenting observations made of the air flow around a Martin PBM-3 flying boat. The observations are part of an analysis to aid in the determination of possible methods of reducing the air drag of the airplane. The behavior of the tufts on the hull and tip floats at various airplane speeds by still and moving pictures taken from an accompanying airplane.
Date: April 1943
Creator: Nelson, William J. & Ebert, John W., Jr.
System: The UNT Digital Library
Laminar-boundary-layer oscillations and transition on a flat plate (open access)

Laminar-boundary-layer oscillations and transition on a flat plate

Report presenting an investigation of oscillations in the laminar boundary layer on a flat plate and their relation to transition to turbulent flow. The characteristics of boundary-layer oscillations were studied most successfully when the oscillations were artificially produced by a vibrating ribbon placed in the boundary layer near the surface. A review of theory regarding laminar-boundary-layer oscillations is provided.
Date: April 1943
Creator: Schubauer, G. B. & Skramstad, H. K.
System: The UNT Digital Library
Laminar-boundary-layer oscillations and transition on a flat plate (open access)

Laminar-boundary-layer oscillations and transition on a flat plate

This is an account of an investigation in which oscillations were discovered in the laminar boundary layer along a flat plate. These oscillations were found during the course of an experiment in which transition from laminar to turbulent flow was being studied on the plate as the turbulence in the wind stream was being reduced to unusually low values by means of damping screens. The first part of the paper deals with experimental methods and apparatus, measurements of turbulence and sound, and studies of transition. A description is then given of the manner in which oscillations were discovered and how they were found to be related to transition, and then how controlled oscillations were produced and studied in detail.
Date: April 1943
Creator: Schubauer, G. B. & Skramstad, H. K.
System: The UNT Digital Library
Observations of compressibility phenomena in flight (open access)

Observations of compressibility phenomena in flight

Report presenting compressibility phenomena under flight conditions on the XF2A-2 airplane, which was subjected to a series of dives and pull-outs at speeds up to 550 miles per hour corresponding to Mach numbers of 0.74. Results regarding time histories, pressure data, drag coefficient, and elevator control force are provided.
Date: April 1943
Creator: Rhode, Richard V. & Pearson, H. A.
System: The UNT Digital Library
Physical Data on Certain Alloys for High Temperature Applications (open access)

Physical Data on Certain Alloys for High Temperature Applications

Report presenting data constituting a summary of the physical properties of 120 samples of metal alloys, representing 86 different compositions which have been investigated for their suitability as turbosupercharger wheel materials. Some of the reported data include the chemical composition, fabrication procedure, tensile-test and hardness values at room temperature, and tensile and rupture-test characteristics at 1200 degrees Fahrenheit.
Date: April 1943
Creator: White, A. E.; Freeman, J. W. & Rote, F. B.
System: The UNT Digital Library
Review of Flight Tests of NACA C and D Cowlings on the XP-42 Airplane (open access)

Review of Flight Tests of NACA C and D Cowlings on the XP-42 Airplane

Report presenting the results of flight tests of the performance and cooling characteristics of three NACA D cowlings and of a conventional NACA C cowling on the XP-42 airplane. The D cowling is, generally, characterized by the use of an annular inlet and diffuser section for the engine-cooling air. An increase in maximum speed was noted in the XP-42 airplane due to the change from a C cowling to a D cowling.
Date: April 1943
Creator: Johnston, J. Ford
System: The UNT Digital Library
A Study of the Effects of Radii of Gyration and Altitude on Aileron Effectiveness at High Speed (open access)

A Study of the Effects of Radii of Gyration and Altitude on Aileron Effectiveness at High Speed

"The variation in the necessary aileron control and in the time required to bank to 45 degrees and 90 degrees with altitude and radii of gyration for a typical fighter or a pursuit airplane have been computed and are presented herein." The lateral motions and impact pressure for several conditions of flight are provided. The report concludes that "the aileron system...should be designed for rolling-moment requirements at high altitude and the hinge-moment limitations at low altitude".
Date: April 1943
Creator: Fehlner, Leo F.
System: The UNT Digital Library
Theoretical Determination of Axial Fan Performance (open access)

Theoretical Determination of Axial Fan Performance

"The report presents a method for the computation of axial fan characteristics. The method is based on the assumption that the law of constancy of the circulation along the blade holds, approximately, for all fan conditions for which the blade elements operate at normal angles of attack (up to the stalling angles). Pressure head coefficient K(sub a) and power coefficient K(sub u) for the force components in the axial and tangential directions, respectively, and analogous to the lift and drag coefficients C(sub y) and C(sub x) are conveniently introduced" (p. 1).
Date: April 1943
Creator: Struve, E.
System: The UNT Digital Library
Vibration Surveys of the P-40 Rudder and Fin-Rudder Assembly (open access)

Vibration Surveys of the P-40 Rudder and Fin-Rudder Assembly

"The following surveys on the vibration response of the P-40 rudder and fin-rudder assembly were conducted during the fall of 1942 for the purpose of obtaining information on the flutter characteristics of high-speed airplanes of known performance. The tests on the rudder alone were made with the rudder suspended in a floating condition; the tests on the fin-rudder unit were made with the fin rigidly fastened to a concrete base" (p. 1). A variety of figures and diagrams for the assembly are provided.
Date: April 1943
Creator: Theodorsen, Theodore & Regier, Arthur A.
System: The UNT Digital Library
Vibration Surveys of the P-47-B Rudder and Fin-Rudder Assembly (open access)

Vibration Surveys of the P-47-B Rudder and Fin-Rudder Assembly

Report presenting a study of the flutter characteristics of the P-47 tail assembly, which included replacing the original fabric-covered rudder with a metal-covered rudder and reinforcing the fin. Figures are provided for different configurations and the cycles per second under the same conditions are provided.
Date: April 1943
Creator: Theodorsen, Theodore & Regier, Arthur A.
System: The UNT Digital Library