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Development and Construction of an Interferometer for Optical Measurements of Density Fields

Description: "A method of interference is described in the present report which promises profitable application in aeronautical research. The physical foundation of the method and a simple method of adjustment are briefly discussed. The special technical construction of the instrument is described which guarantees its use also in the case of vibrations of the surrounding space and permits the investigation of unsteady phenomena" (p. 1).
Date: September 1947
Creator: Zobel
Partner: UNT Libraries Government Documents Department

NACA Conference on Aircraft Loads, Structures, and Flutter

Description: "This document contains reproductions of technical papers on some of the most recent research results on aircraft loads, flutter, and structures from the NACA laboratories. These papers were presented by members of the staff of the NACA laboratories at the Conference held at the Langley Aeronautical Laboratory March 5, 6, and 7, 1957. The primary purpose of this Conference was to convey to contractors of the military services and others concerned with the design of aircraft these recent research results and to provide those attending an opportunity to discuss the results" (p. 6).
Date: March 5, 1957
Partner: UNT Libraries Government Documents Department

NACA: University Conference on Aerodynamics: A Compilation of the Papers Presented

Description: This document contains reproductions of the technical papers presented at the NACA - University Conference on Aerodynamics held at the Langley Aeronautical Laboratory on June 21, 22, and 23, 1948. The conference was held in recognition of the difficulties, imposed by security restrictions, in keeping abreast of the rapid advances in aerodynamics. The papers were prepared to review the status of a number of fields of interest, to summarize the more important wartime advances that are no longer classified, and to orient reference material for further study.
Date: 1948-06-21/1948-06-23
Partner: UNT Libraries Government Documents Department

Pressure Distribution Measurements on a Turbine Rotor Blade Passing Behind a Turbine Nozzle Lattice

Description: "As a turbine rotor turns, the blades traverse the wake zones of the nozzle vanes. A periodic fluctuation of the pressure distribution around the circumference of the rotor blade is therefore caused. It was desired to investigate quantitatively this effect. At the same time, the magnitude of the force acting upon one profile of the rotor-blade lattice at various positions of this lattice relative to the nozzle lattice was to be determined" (p. 1).
Date: September 1947
Creator: Hausenblas
Partner: UNT Libraries Government Documents Department

NACA Conference on Aerodynamics of High Speed Aircraft

Description: "This document contains reproductions of technical papers presented by staff members of the NACA Laboratories at the NACA Conference on Aerodynamics of High-Speed Aircraft held at the Langley Aeronautical Laboratory November 1, 2, and 3, 1955. The primary purpose of the conference was to convey to contractors of the military services and others concerned with the design of aircraft the results of recent research and to provide those attending with an opportunity to discuss these results. The papers in this document are in the same form in which they were orally presented at the conference to facilitate their prompt distribution" (p. vii).
Date: 1955-11-01/1955-11-03
Partner: UNT Libraries Government Documents Department

The aerodynamic effects of wing cut-outs

Description: From Introduction: "The information now available concerning wing cut-outs or applicable to the analysis of their effects is plentiful (references 1 to 7) but too disconnected and unorganized to be of the greatest possible usefulness. In connection with the interference program being conducted in the N.A.C.A. varible-density wind tunnel, an analysis was therefore made of existing material to determine the qualitative effects of the different features of wing cut-outs, and to obtain means of calculating wing characteristics as affected by them."
Date: 1934
Creator: Sherman, Albert
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of a two-blade NACA 10-(3)(062)-045 propeller and of a two-blade NACA 10-(3)(08)-045 propeller

Description: Report discussing characteristics are given for the two-blade NACA 10-(3)(062)-045 propeller and for the two-blade NACA 10-(3)(08)-045 propeller over a range of advance ratio from 0.5 to 3.8, through a blade-angle range from 20 degrees to 55 degrees measured at the 0.75 radius. Maximum efficiencies of the order of 91.5 to 92 percent were obtained for the propellers. The propeller with the thinner airfoil sections over the outboard portion of the blades, the NACA 10-(3)(062)-045 propeller, had lower losses at high tip speeds, the difference amounting to about 5 percent at a helical tip Mach number of 1.10.
Date: January 1953
Creator: Solomon, William
Partner: UNT Libraries Government Documents Department

Analysis of factors affecting net lift increment attainable with trailing-edge split flaps on tailless airplanes

Description: From Introduction: "The lift increments of different flap arrangements were determined by the method of reference 1 with a simple chord correction factor being applied. This procedure is somewhat similar in basic principles to the method of reference 2. The accuracy of the present method was determined by calculating by means of this method the lift and moment increments of flaps on 10 different finite wing-flap combinations for which wind-tunnel data were available."
Date: September 1944
Creator: Maggin, Bernard
Partner: UNT Libraries Government Documents Department

Tests of Airfoils Designed to Delay the Compressibility Burble

Description: Development of airfoil sections suitable for high-speed applications has generally been difficult because little was known of the flow phenomenon that occurs at high speeds. A definite critical speed has been found at which serious detrimental flow changes occur that lead to serious losses in lift and large increases in drag. This flow phenomenon, called the compressibility burble, was originally a propeller problem, but with the development of higher speed aircraft serious consideration must be given to other parts of the airplane. Fundamental investigations of high-speed airflow phenomenon have provided new information. An important conclusion of this work has been the determination of the critical speed, that is, the speed at which the compressibility burble occurs. The critical speed was shown to be the translational velocity at which the sum of the translational velocity and the maximum local induced velocity at the surface of the airfoil or other body equals the local speed of sound. Obviously then higher critical speeds can be attained through the development of airfoils that have minimum induced velocity for any given value of the lift coefficient. Presumably, the highest critical speed will be attained by an airfoil that has uniform chordwise distribution of induced velocity or, in other words, a flat pressure distribution curve. The ideal airfoil for any given high-speed application is, then, that form which at its operating lift coefficient has uniform chordwise distribution of induced velocity. Accordingly, an analytical search for such airfoil forms has been conducted and these forms are now being investigated experimentally in the 23-inch high-speed wind tunnel. The first airfoils investigated showed marked improvement over those forms already available, not only as to critical speed buy also the drag at low speeds is decreased considerably. Because of the immediate marked improvement, it was considered desirable to extend the ...
Date: June 1939
Creator: Stack, John
Partner: UNT Libraries Government Documents Department

Preliminary analysis of axial-flow compressors having supersonic velocity at the entrance of the stator

Description: Report presenting a supersonic compressor design with supersonic velocity at the entrance of the stator on the assumption of two-dimensional flow. The rotor and stator losses assumed in the analysis are based on the results of preliminary supersonic cascade tests. The starting conditions and stability of the flow in rotor and stator are discussed, and the desirability of the variable-geometry stators and adjustable guide vanes is indicated.
Date: September 12, 1949
Creator: Ferri, Antonio
Partner: UNT Libraries Government Documents Department

The advantages of uniform fuel distribution for air-cooled engines from considerations of cooling requirements and fuel economy

Description: From Introduction: "The purpose of this report is to show by analysis of existing data, pending direct experimental determination, the extent to which nonuniform distribution of fuel to cylinders of a multicylinder engine can produce temperature deviation and the benefits to be anticipated from attainment of uniform fuel distribution."
Date: December 1943
Creator: Nielson, Jack
Partner: UNT Libraries Government Documents Department

The application of the statistical theory of extreme values to gust-load problems

Description: From Introduction: "Recent developments in the statistical theory of extreme values (references 4 to 10) have indicated a somewhat more rational approach to the problem of predicting the probability of occurrence The present report summarizes some of these findings, indicates the method of application, and evaluates their applicability to certain gust-load problems ."
Date: July 22, 1949
Creator: Press, Harry
Partner: UNT Libraries Government Documents Department

Application of a numerical procedure to stress analysis of stringer-reinforced panels

Description: From Introduction: "In the present paper a numerical procedure for the stress analysis of flat-sheet and stringer combinations of arbitrary construction and loading is presented and applied to axially loaded panels and to the reinforced covers of box beams."
Date: March 1945
Creator: Kempner, Joseph
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation of alternative propellers operating behind deflected wing flaps for the XB-36 airplane

Description: Report discussing testing on the aerodynamic characteristics of two pusher propellers with the same plan form but different airfoil sections behind a slotted flap on the XD-36 airplane. Testing was carried out over the range of blade angles and flap deflections necessary to cover all flight conditions. The effects of flaps and of tip Mach number are described in detail.
Date: December 1945
Creator: Boxer, Emanuel
Partner: UNT Libraries Government Documents Department

Wind Tunnel Investigation at Low Speed of Aerodynamic Characteristics of Army Chemical Corps Model E-112 Bomblets with Span Chord Ratio of 2 - 1

Description: An experimental investigation has been made in the Langley stability tunnel to determine the aerodynamic characteristics of the Army Chemical Corps model E-112 bomblets with span-chord ratio of 2:1. A detailed analysis has not been made; however, the results showed that all the models were spirally unstable and that a large gap between the model tips and end plates tended to reduce the instability.
Date: December 26, 1956
Creator: Letko, William
Partner: UNT Libraries Government Documents Department

Aerodynamic problems in the design of efficient propellers

Description: From General Analysis: "The purpose of part I of this paper is to show how the loading that gives the minimum induced energy loss can be obtained from rather elementary considerations and to present design charts from which such a plan form can be quickly obtained for any set of design conditions."
Date: August 1942
Creator: Feldman, Lewis
Partner: UNT Libraries Government Documents Department

A theoretical investigation of the rolling oscillations of an airplane with ailerons free

Description: Report discusses an analysis of the stability of an airplane with ailerons free, with particular attention to the motions when the ailerons have a tendency to float against the wind. Information about the aerodynamic balance of the plane and oscillations that may be encountered are included. The effects of friction in the control system is also explored.
Date: January 1944
Creator: Cohen, Doris
Partner: UNT Libraries Government Documents Department

Zero-lift drag of a large fuselage cavity and a partially submerged store on a 52.5 degree sweptback-wing-body configuration as determined from free-flight tests at Mach numbers of 0.7 to 1.53

Description: Report presenting a free-flight investigation of a rocket-propelled model at a range of Mach numbers from 0.7 to 1.53 to determine the drag at zero lift of a configuration with a large fuselage cavity and partially submerged store. Testing was performed out of a desire to determine if large stores can be attached to aircraft wings without negatively affecting the aerodynamic properties. Results regarding total drag and pressure drag are provided.
Date: February 26, 1957
Creator: Hoffman, Sherwood
Partner: UNT Libraries Government Documents Department

The additional-mass effect of plates as determined by experiments

Description: From Introduction: "The apparent increase in the inertia properties of a body moving in a fluid medium has been called the additional-mass effect. This report presents a resume of test procedures and results of experimental determinations of the additional-mass effect of flat plates. In addition to data obtained from various foreign sources and from a NACA investigation in 1933, the results of tests recently conducted by the National Advisory Committee for Aeronautics are included."
Date: 1941
Creator: Gracey, William
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics at high speeds of a two-blade NACA 10-(3)(062)-045 propeller and of a two-blade NACA 10-(3)(08)-045 propeller

Description: From Introduction: "The aerodynamic characteristics of a series of 10-foot-diameter propellers are being investigated in the Langley 16-foot high-speed tunnel in a comprehensive propeller research program. Using high-critical-speed NACA 16-series airfoil sections (reference 1), these propellers are designed to have Betz minimum induced-energy loss loading (reference 2) for a blade angle of 45^o at the 0.7 radius, when used as a four-blade propeller operating at an advance ratio of approximately 2.1 The ultimate purpose of the program is to determine the influence upon propeller design factors and of compressiblity; the propeller tests reported herein form part of the investigation of the effects of blade-section thickness ratio."
Date: October 1, 1948
Creator: Solomon, William
Partner: UNT Libraries Government Documents Department

Aerodynamic heating and the deflection of drops by an obstacle in an air stream in relation to aircraft icing

Description: From Summary: "Two topics of interest to persons attempting to apply the heat method of preventing ice formation on aircraft are considered. Surfaces moving through air at high speed are shown, both theoretically and experimentally, to be subject to important aerodynamic heating effects that will materially reduce the heat required to prevent ice. Numerical calculations of the path of water drops in an air stream around a circular cylinder are given. From these calculations, information is obtained on the percentage of the swept area cleared of drops."
Date: October 1940
Creator: Kantrowitz, Arthur
Partner: UNT Libraries Government Documents Department