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Two-Dimensional Irrotational Transonic Flows of a Compressible Fluid

Description: The methods of NACA TN No. 995 have been slightly modified and extended in include flows with circulation by considering the alteration of the singularities of the incompressible solution due to the presence of the hypergeometric functions in the analytic continuation of the solution. It was found that for finite Mach numbers the only case in which the nature of the singularity can remain unchanged is for a ratio of specific heats equal to -1. From a study of two particular flows it seems that the effect of geometry cannot be neglected, and the conventional "pressure-correction" formulas are not valid, even in the subsonic region if the body is thick, especially if there is a supersonic region in the flow.
Date: June 1948
Creator: Kuo, Yung-Huai
Partner: UNT Libraries Government Documents Department

Tables and charts of flow parameters across oblique shocks

Description: Shock-wave equations have been evaluated for a range of Mach number in front of the shock from 1.05 to 4.0. Mach number behind the shock, pressure ratio, derivation of flow, and angle of shock are presented on charts. Values are also included for density ratio and change in entropy.
Date: August 1948
Creator: Neice, Mary M.
Partner: UNT Libraries Government Documents Department

Two-dimensional subsonic compressible flows past arbitrary bodies by the variational method

Description: Instead of solving the nonlinear differential equation which governs the compressible flow, an approximate method of solution by means of the variational method is used. The general problem of steady irrotational flow past an arbitrary body is formulated. Two examples were carried out, namely, the flow past a circular cylinder and the flow past a thin curved surface. The variational method yields results of velocity and pressure distributions which compare excellently with those found by existing methods. These results indicate that the variational method will yield good approximate solution for flow past both thick and thin bodies at both high and low Mach numbers.
Date: March 1951
Creator: Wang, Chi-Teh
Partner: UNT Libraries Government Documents Department

Investigation of frequency-response characteristics of engine speed for a typical turbine-propeller engine

Description: Report presenting the experimental frequency-response characteristics of engine speed for a typical turbine-propeller engine. The data were obtained by subjecting the engine to sinusoidal variation of fuel flow and propeller-blade-angle inputs. A comparison of the analytical and experimental results is provided.
Date: September 1950
Creator: Taylor, Burt L., III & Oppenheimer, Frank L.
Partner: UNT Libraries Government Documents Department

An investigation of forward-located fixed spoilers and deflectors as gust alleviators on an unswept-wing model

Description: Report presenting an investigation in the 300 mph 7- by 10-foot tunnel and gust tunnel to determine the static longitudinal aerodynamic characteristics an the gust-alleviation capabilities of forward-located fixed spoilers, deflectors, or a spoiler-deflector combination on a simulated transport airplane model with an unswept wing. Results regarding the static/force test, dynamic/gust-tunnel test, and short-period frequency and damping are provided.
Date: June 1956
Creator: Croom, Delwin R.; Shufflebarger, C. C. & Huffman, Jarrett K.
Partner: UNT Libraries Government Documents Department

Investigation of far noise field of jets 2: comparison of air jets and jet engines

Description: Report presenting a comparison of the noise generation of air jets and turbojet engines under similar free-flight conditions. Results regarding a comparison of the sound power, afterburner data, spectrum measurements, noise data for engine thrust, and frequency distribution for the two engines are provided.
Date: January 1956
Creator: Coles, Willard D. & Callaghan, Edmund E.
Partner: UNT Libraries Government Documents Department

Wing-body interference at supersonic speeds with an application to combinations with rectangular wings

Description: Report presenting the development of an exact theoretical method that permits the determination of the pressure field of a wing-body combination with a circular body and a wing with supersonic leading and trailing edges. Detailed calculations were performed for wing-body combinations composed of rectangular wings mounted at incidence on bodies at zero angle of attack for effective chord-radius ratios of 4 or less.
Date: April 1952
Creator: Nielsen, Jack N. & Pitts, William C.
Partner: UNT Libraries Government Documents Department

Stability and control characteristics at low speed of an airplane model having a 38.7 degree sweptback wing with aspect ratio 4.51, taper ratio 0.54, and conventional tail surfaces

Description: Report presenting a low-speed wind-tunnel investigation of a scale model of an airplane with a 38.7 degree sweptback wing with an aspect ratio of 4.51, a taper ratio of 0.54, and conventional tail surfaces. Results regarding the lift characteristics, longitudinal stability, longitudinal control, directional stability, lateral control, and directional control are provided.
Date: December 1948
Creator: Lockwood, Vernard E. & Watson, James M.
Partner: UNT Libraries Government Documents Department

Exploratory investigation of the effectiveness of biplane wings with large-chord double slotted flaps in redirecting a propeller slipstream downward for vertical take-off

Description: Results are presented from static-force tests on biplane wings with large-chord double slotted flaps which turn the slipstream of a single counter rotating propeller downward for vertical take-off. The investigation provided information on the effect of chord length, flap deflection, propeller position, end plates, fuselage, and ground proximity on the efficiency of the wing system in turning the propeller slipstream.
Date: October 1956
Creator: Kirby, Robert H.
Partner: UNT Libraries Government Documents Department

A Flight Evaluation and Analysis of the Effect of Icing Conditions on the ZPG-2 Airship

Description: A series of test flights was conducted by the U. S. Navy over a 3- year period to evaluate the effects of icing on the operation of the ZPG-2 airship. In supercooled. clouds, ice formed only on the forward edges of small protuberances and wires and presented no serious hazard to operation. Ice accretions of the glaze type which occurred in conditions described as freezing drizzle adversely affected various components to a somewhat greater extent. The results indicated, a need for protection of certain components such as antennas, propellers, and certain parts of the control system. The tests showed that icing of the large surface of the envelope occurred only in freezing rain or drizzle. Because of the infrequent occurrence of these conditions, the potential maximum severity could not be estimated from the test results. The increases in heaviness caused by icing in freezing rain and drizzle were substantial, but well within the operational capabilities of the airship. In order to estimate the potential operational significance of icing in freezing rain, theoretical calculations were used to estimate: (1) the rate of icing as a function of temperature and rainfall intensity, (2) the climatological probability of occurrence of various combinations of these variables, and (3) the significance of the warming influence of the ocean in alleviating freezing-rain conditions. The results of these calculations suggest that, although very heavy icing rates are possible in combinations of low temperature and high rainfall rate, the occurrence of such conditions is very infrequent in coastal areas and virtually impossible 200 or 300 miles offshore.
Date: April 1, 1958
Creator: Lewis, Willilam & Perkins, Porter J., Jr.
Partner: UNT Libraries Government Documents Department

The Flettner rotor ship in the light of the Kutta-Joukowski theory and of experimental results

Description: In this paper the fundamental principles of the Flettner rotor ship (Reference I) are discussed in the light of the Kutta-Joukowski theory and available experimental information on the subject. A brief exposition of the Kutta-Joukowski theory is given and the speed of the rotor ship Buckau computed, first by using effective propulsive force obtained by the above theory, and then by direct application of wind tunnel data.
Date: October 1, 1925
Creator: Rizzo, Frank
Partner: UNT Libraries Government Documents Department

The flexible mounting of an airplane engine

Description: Discussed here is the suggested installation of the 'unbalanced' 8-cylinder VE-engine. The suggestion was that a flexible mounting be used instead of bolting the engine rigidly to the airplane structure. It was concluded that a flexible connection between the engine and the airplane is probably possible. A flexible connection primarily diminishes the vibrations due to inertia and, to a lesser degree, those due to torque variation. However, engines vibrate more when freely suspended than when rigidly mounted, and this vibration has a detrimental effect on all connections between the engine and the airplane. Therefore, in view of the relatively insignificant advantages which may be derived from the elastic suspension of the engine, the present rigid mounting is to be preferred. Vibration reduction can be achieved by incorporating in the fuselage as many of the rigid airplane parts as possible.
Date: July 1923
Creator: Kutzbach, K.
Partner: UNT Libraries Government Documents Department