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Performance of an exhaust-gas "blowdown" turbine on a nine-cylinder radial engine (open access)

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

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.
System: The UNT Digital Library
Thermodynamic Design of Double-Panel, Air-Heated Windshields for Ice Prevention (open access)

Thermodynamic Design of Double-Panel, Air-Heated Windshields for Ice Prevention

Report details the development of design equations for double-panel, air-heated windshields with ice prevention properties. The application of the equations and suggestions for experimental flight testing are described.
Date: June 1943
Creator: Kushnick, Jerome L.
System: The UNT Digital Library
The Flow of a Compressible Fluid Past a Circular Arc Profile (open access)

The Flow of a Compressible Fluid Past a Circular Arc Profile

Report presenting the use of the Ackeret iteration process to obtain higher approximations than that of Prandtl and Glauert for the flow of a compressible fluid past a circular arc profile. The procedure is to expand the velocity potential in a power series of the camber coefficient.
Date: October 1944
Creator: Kaplan, Carl
System: The UNT Digital Library
Compressible potential flow with circulation about a circular cylinder (open access)

Compressible potential flow with circulation about a circular cylinder

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.
System: The UNT Digital Library
An Investigation of a Thermal Ice-Prevention System for a C-46 Cargo Airplane 2: The Design, Construction, and Preliminary Tests of the Exhaust-Air Heat Exchanger (open access)

An Investigation of a Thermal Ice-Prevention System for a C-46 Cargo Airplane 2: The Design, Construction, and Preliminary Tests of the Exhaust-Air Heat Exchanger

Report presenting an investigation of an exhaust-air heat exchanger, which has been designed, constructed, and flight-tested for a C-46 cargo airplane. The primary purpose of the investigation was to provide the C-46 airplane with a satisfactory source of heated air and to continue the development of the heat exchanger as a part of thermal ice-prevention equipment. Results indicated that the required thermal output and desired air-temperature rise have been achieved and that the exchanger is suitable for use in the C-46 airplane.
Date: February 1945
Creator: Jackson, Richard
System: The UNT Digital Library
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 (open access)

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

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
System: The UNT Digital Library
Application of Spring Tabs to Elevator Controls (open access)

Application of Spring Tabs to Elevator Controls

Report presenting equations for calculating the stick-force characteristics obtained with a spring-tab type of elevator control. The main problems encountered in the design of the satisfactory elevator spring tab are to provide stick forces in the desired range, to maintain the force per g sufficiently constant throughout the speed range, to avoid undesirable "feel" of the control in ground handling, and to prevent flutter.
Date: October 1944
Creator: Phillips, William H.
System: The UNT Digital Library
On the Flow of a Compressible Fluid by the Hodography Method 2: Fundamental Set of Particular Flow Solutions of the Chaplygin Differential Equation (open access)

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

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
System: The UNT Digital Library
NACA Investigation of a Jet-Propulsion System Applicable to Flight (open access)

NACA Investigation of a Jet-Propulsion System Applicable to Flight

"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.
System: The UNT Digital Library
A Method of Estimating the Knock Rating of Hydrocarbon Fuel Blend (open access)

A Method of Estimating the Knock Rating of Hydrocarbon Fuel Blend

"The usefulness of the knock ratings of pure hydrocarbon compounds would be increased if some reliable method of calculating the knock ratings of fuel blends was known. The purpose of this study was to investigate the possibility of developing a method of predicting the knock ratings of fuel blends" (p. 1).
Date: 1943
Creator: Sanders, Newell D.
System: The UNT Digital Library
The effect of altitude on cooling (open access)

The effect of altitude on cooling

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.
System: The UNT Digital Library
The effect of exhaust-stack shape on the design and performance of the individual cylinder exhaust-gas jet-propulsion system (open access)

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

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.
System: The UNT Digital Library
The problem of longitudinal stability and control at high speeds (open access)

The problem of longitudinal stability and control at high speeds

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
System: The UNT Digital Library
Wind-Tunnel Procedure for Determination of Critical Stability and Control Characteristics of Airplanes (open access)

Wind-Tunnel Procedure for Determination of Critical Stability and Control Characteristics of Airplanes

"This report outlines the flight conditions that are usually critical in determining the design of components of an airplane which affect its stability and control characteristics. The wind-tunnel tests necessary to determine the pertinent data for these conditions are indicated, and the methods of computation used to translate these data into characteristics which define the flying qualities of the airplane are illustrated" (p. 1).
Date: April 1944
Creator: Goett, Harry J.; Jackson, Roy P. & Belsley, Steven E.
System: The UNT Digital Library
A method for calculating heat transfer in the laminar flow region of bodies (open access)

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

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.
System: The UNT Digital Library
Calculations of Economy of 18-Cylinder Radial Aircraft Engine With Exhaust-Gas Turbine Geared to the Crankshaft at Cruising Speed (open access)

Calculations of Economy of 18-Cylinder Radial Aircraft Engine With Exhaust-Gas Turbine Geared to the Crankshaft at Cruising Speed

Report presenting calculations based on dynamometer test-stand data on an 18-cylinder radial engine made to determine the improvement in fuel consumption that can be obtained by gearing an exhaust-gas turbine to the engine crankshaft in order to increase the engine shaft work.
Date: December 1945
Creator: Hannum, Richard W.
System: The UNT Digital Library
Nitrided-steel piston rings for engines of high specific power (open access)

Nitrided-steel piston rings for engines of high specific power

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.
System: The UNT Digital Library
Comparison of Vee-Type and Conventional Tail Surfaces in Combination with Fuselage and Wing in the Variable-Density Tunnel (open access)

Comparison of Vee-Type and Conventional Tail Surfaces in Combination with Fuselage and Wing in the Variable-Density Tunnel

"The pitching and the yawing moments of a vee-type and a conventional type of tail surface were measured. The tests were made in the presence of a fuselage and a wing-fuselage combination in such a way as to determine the moments contributed by the tail surfaces" (p. 1).
Date: July 1941
Creator: Greenberg, Harry
System: The UNT Digital Library
Wall interference in a two-dimensional-flow wind tunnel with consideration of the effect of compressibility (open access)

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

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.
System: The UNT Digital Library
Notes on the Effect of Surface Distortions on the Drag and Critical Mach Number of Airfoils (open access)

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

"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
System: The UNT Digital Library
The Calculation of Span Load Distributions of Swept-Back Wings (open access)

The Calculation of Span Load Distributions of Swept-Back Wings

"Span load distributions of swept-back wings have been calculated. The method used was to replace the wing with a bound vortex at the quarter-chord line and to calculate the downwash due to the system of bound and trailing vortices to conform at the three-quarter-chord line to the slope of the flat-plate wing surface. Results are given for constant-chord and 5:1 tapered plan forms, for sweep-back angles of 0 degrees, 30 degrees, and 45 degrees, and for aspect ratios of 3, 6, and 9" (p. 1).
Date: December 1941
Creator: Mutterperl, William
System: The UNT Digital Library
Derivation of charts for determining the horizontal tail load variation with any elevator motion (open access)

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

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.
System: The UNT Digital Library
Methods of Analyzing Wind-Tunnel Data for Dynamic Flight Conditions (open access)

Methods of Analyzing Wind-Tunnel Data for Dynamic Flight Conditions

"The effects of power on the stability and the control characteristics of an airplane are discussed and methods of analysis are given for evaluating certain dynamic characteristics of the airplane that are not directly discernible from wind-tunnel tests alone. Data are presented to show how the characteristics of a model tested in a wind tunnel are affected by power. The response of an airplane to a rolling and a yawing disturbance is discussed, particularly in regard to changes in wing dihedral and fin area" (p. 1).
Date: October 1941
Creator: Donlan, C. J. & Recant, I. G.
System: The UNT Digital Library
Icing Tests of Aircraft-Engine Induction Systems (open access)

Icing Tests of Aircraft-Engine Induction Systems

Report presenting a program of icing tests conducted on an aircraft-engine induction system consisting of a Wright R-1820, G-200 blower section, Holley 1375-F carburetor and adapter, and specially built air scoop. The primary purpose of the investigation was to determine the effect of a number of possible factors on icing of engine-induction systems, including carburetor-air temperature, air-moisture content, water-droplet size, throttle opening, mixture ratio, rate of air flow, altitude, and others.
Date: January 1943
Creator: Kimball, Leo B.
System: The UNT Digital Library