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Flight Tests of Modifications to Improve the Aileron Control Characteristics of a North American XP-51 Airplane (AC No. 41-38)

Description: Investigations were undertaken to improve the ailerons of a P-51 fighter so as to obtain greater effectiveness without increasing the stick forces. Modifications consisted of increasing the deflection range of the aileron to 70 percent and changing the original concave section to a thick section with beveled trailing edge. Results of the modified ailerons showed an increase in effectiveness over the original aileron of 70 percent at low speed and 55 percent at high speeds.
Date: June 1942
Creator: White, M. D. & Hoover, Herbert H.
Partner: UNT Libraries Government Documents Department

The effect of exhaust-stack shape on the design and performance of the individual cylinder exhaust-gas jet-propulsion system

Description: Report presenting tests on a single-cylinder, air-cooled engine to determine the effect of several different exhaust-stack shapes on the design and performance of the individual cylinder exhaust-gas jet-propulsion systems. Results regarding the effect of nozzle area and stack shape on exhaust-gas jet thrust, effect of nozzle area and stack shape on overall performance for the S-shape, the 90 degree bend, and the 180 degree bend, the effect on the shape on engine power and volumetric efficiency, and the effect of a branched stack on engine power are provided.
Date: November 1942
Creator: Turner, L. Richard & Humble, Leroy V.
Partner: UNT Libraries Government Documents Department

The problem of longitudinal stability and control at high speeds

Description: Report discussing the difficulty in pulling of high-speed dives, which is primarily due to the effect of compressibility on the lift of the wing. Some of the means described for providing increased longitudinal control include auxiliary flaps and a controllable stabilizer.
Date: November 1943
Creator: Hood, Manley J. & Allen, H. Julian
Partner: UNT Libraries Government Documents Department

Tests of a thermal ice-prevention system for a wing leading-edge landing-light installation

Description: Report discussing the creation of a thermal ice-prevention system of a bomber-type airplane to provide protection against ice and fog formations on the transparent fairing over the landing light in the wing leading edge. A comparison between the design performance and actual performance showed that the outer-surface heat-transfer coefficient was correctly predicted, but the inner-surface heat-transfer coefficient was four times as large, leading to failure of the plastic fairing.
Date: December 1944
Creator: Hillendahl, Wesley H.
Partner: UNT Libraries Government Documents Department

Intercooler cooling-air weight flow and pressure drop for minimum drag loss

Description: Report presenting an analysis of the power losses in airplane flight of cross-flow plate and tubular intercoolers to determine the cooling-air weight flow and pressure drop that give minimum total power loss for any given cooling effectiveness. The investigation covers a range of flight conditions of altitude, airspeed, lift-drag ratio, supercharger-pressure ratio, and adiabatic efficiency.
Date: April 1944
Creator: Reuter, J. George & Valerino, Michael F.
Partner: UNT Libraries Government Documents Department

Flight tests of thermal ice-prevention equipment in the XB-24F airplane

Description: Report presenting performance tests of thermal ice-prevention equipment designed and installed in the XB-24F airplane in icing and non-icing conditions. The recorded temperature and air-flow data, and the calculated quantities of heat flow throughout the system are presented in tabular form.
Date: October 7, 1943
Creator: Neel, Carr B. & Jones, Alun R.
Partner: UNT Libraries Government Documents Department

Wall interference in a two-dimensional-flow wind tunnel with consideration of the effect of compressibility

Description: Report presenting tunnel-wall corrections for an airfoil of finite thickness and camber in a two-dimensional-flow wind tunnel. The theory takes account of the effects of the wake of the airfoil and of the compressibility of the fluid and is based on the assumption that the chord of the airfoil is small in comparison with the height of the tunnel. The theoretical results are compared with the small amount of low-speed experimental data available and agreement is seen to be satisfactory, even for relatively large values of the chord-height ratio.
Date: December 1944
Creator: Allen, H. Julian & Vincenti, Walter G.
Partner: UNT Libraries Government Documents Department

Nitrided-steel piston rings for engines of high specific power

Description: Report presenting testing of several designs of nitrided-steel piston rings under variable conditions of output. Testing indicated the importance of good surface finish and conformity of the ring to the bore. Results regarding temperature tests, single-cylinder-engine tests, and multicylinder-engine tests are provided.
Date: April 1944
Creator: Collins, John H., Jr.; Bisson, Edmond E. & Schmiedlin, Ralph F.
Partner: UNT Libraries Government Documents Department

A general representation for axial-flow fans and turbines

Description: From Summary: "A general representation of fan and turbine arrangements on a single classification chart is presented which is made possible by a particular definition of the stage of an axial-flow fan or turbine. Several unconventional fan and turbine arrangements are indicated and the applications of these arrangements are discussed."
Date: June 1945
Creator: Perl, W. & Tucker, M.
Partner: UNT Libraries Government Documents Department

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

Description: Report presenting equations relating the wing and tail loads are derived for a unit elevator displacement. The equations are converted into a nondimensoinal form and charts are given that can be used to predict wing- and tail-load-increment variation for any type of elevator motion and for degrees of airplane stability.
Date: January 1943
Creator: Pearson, Henry A.
Partner: UNT Libraries Government Documents Department

A method for studying the hunting oscillations of and airplane with a simple type of automatic control

Description: Report presenting a method for predicting the amplitude and frequency, under certain simplifying conditions, of the hunting oscillations of an automatically controlled aircraft with lag in the control system or in response of the aircraft to the controls. Formulas are given expressing the response to a variation of signal in terms of response to a unit signal.
Date: May 1944
Creator: Jones, Robert T.
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

The effect of altitude on cooling

Description: Report presenting variables that control the cooling of liquid-cooled and air-cooled engines and then to show by illustrations how either engine may be cooled at any desired altitude. Cooling was found to not be the limiting factor in the design of high-altitude airplanes and was also not found to be a valid reason for selecting either liquid- or air-cooled engines for high-altitude operation.
Date: March 1943
Creator: Brevoort, Maurice J.; Joyner, Upshur T. & Wood, George P.
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

Pressure drop in tank and float vent tubes on diving airplanes

Description: Report presenting an experiment regarding tank and float venting conditions that exist on diving airplanes undergoing rapid changes in altitude. The results indicated that large pressure differences build up between the outside and inside of tanks and floats on diving airplanes unless the correct size of venting tube is used.
Date: January 1939
Creator: Waldron, C. D.
Partner: UNT Libraries Government Documents Department

Compressible potential flow with circulation about a circular cylinder

Description: Report presenting the potential function for flow, with circulation, of a compressible fluid about a circular cylinder, which is obtained in series form including terms of the order of M(exp 4) where M is the Mach number of the free stream. The equations are used to obtain pressure coefficient as a function of Mach number at a point on the surface of the cylinder for different values of circulation.
Date: January 1944
Creator: Heaslet, Max A.
Partner: UNT Libraries Government Documents Department

A method for calculating heat transfer in the laminar flow region of bodies

Description: Report presenting a practical method for determining the chordwise distribution of the rate of heat transfer from the surface of a wing or body of revolution to air. The method is limited to use to the determination of heat transfer fro the forward section of such bodies when the flow is laminar.
Date: December 1942
Creator: Allen, H. Julian & Look, Bonne C.
Partner: UNT Libraries Government Documents Department

Fluid de-icing tests on a Chandler-Evans 1900 CPB-3 carburetor mounted on a Pratt & Whitney R-1830-C4 intermediate rear engine section

Description: Report presenting an investigation of the icing and de-icing characteristics of a Pratt & Whitney R-1830 engine induction system. The current report covers a program to determine the most effective rate and method of injection of de-icing fluid to remove a heavy ice formation from the induction system. Results regarding the flow rates, recovery times, de-icing portions of the runs, and ice formation characteristics are provided.
Date: October 1944
Creator: Galvin, Herman B. & Essex, Henry A.
Partner: UNT Libraries Government Documents Department

A laboratory investigation of the icing characteristics of the Bendix-Stromberg carburetor model PD-12F5 with the Pratt and Whitney R-1830-C4 intermediate rear engine section

Description: Report presenting icing tests on a Bendix-Stromberg PD-12F5 carburetor mounted on a Pratt & Whitney R-1830-C4 intermediate rear engine section. Limiting icing conditions were established for simulated cruising power and simulated rated power over a range of carburetor-air temperatures, and relative humidities are provided.
Date: October 1944
Creator: Galvin, Herman B. & Essex, Henry A.
Partner: UNT Libraries Government Documents Department

Correlation of exhaust-valve temperatures with engine operating conditions and valve design

Description: Report presenting a theory regarding engine-cooling variables from a previous report, which was used as a basis for the development of a semi-empirical equation to correlate exhaust-valve temperature with engine conditions. Results regarding the determination of constants, influences of operating variables on mean effective gas temperatures, thermal-resistance factor, and accuracy of correlating equation are provided.
Date: October 1945
Creator: Zipkin, M. A. & Sanders, J. C.
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation of the effects of spoilers on the characteristics of a low-drag airfoil equipped with a 0.25-chord slotted flap

Description: Report discussing the effects of circular-arc spoilers on the section characteristics of an NACA 66,2-216 airfoil with a 0.25-chord slotted flap. Spoilers were tested on the upper surface of the airfoil, on the lower surface, and on both simultaneously. Only the simultaneous placement of spoilers was found to provide satisfactory results as a lateral control device.
Date: July 23, 1945
Creator: Holtzclaw, Ralph W.
Partner: UNT Libraries Government Documents Department

Visual studies of cylinder lubrication [part] 1: the lubrication of the piston skirt

Description: Report describes the lubrication characteristics of an aircraft-type piston as visually studied in a V-type engine with a glass cylinder. Information about the movement of the piston, the piston rings, and the oil-control rings and their effect on lubrication is included.
Date: September 1945
Creator: Shaw, Milton C. & Nussdorfer, Theodore
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