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Tank Tests of the Effect of Rivet Heads, etc., on the Water Performance of a Seaplane Float, Special Report

Description: "A 1/3.5 full-size model of the Mark V float of the Bureau of Aeronautics, Navy Department, was tested in the NACA tank both with smooth painted bottom surfaces and with roundhead rivets, plate laps, and keel plates fitted to simulate the actual bottom of a metal float. The augmentation in water resistance due to the added roughness was found to be from 10-12% at the hum speed and from 12-14% at high speeds. The effect of the roughness of the afterbody was found to be negligible except at high trims" (p. 1).
Date: June 4, 1936
Creator: Parkinson, J. B. & Robertson, J. B., Jr.
Partner: UNT Libraries Government Documents Department

Estimated Effect of Ring Cowl on the Climb and Ceiling of an Airplane

Description: From Summary: "Although the application of a ring cowl to an airplane with an air-cooled engine increases the maximum L/D and the high speed to an appreciable extent, the performance in climb and ceiling is not increased as much as one would expect without analyzing the conditions. When a ring cowl is installed on an airplane, the propeller is set at a higher pitch to allow the engine to turn its rated r.p.m. at the increased high speed. V/nD is increased and the propeller efficiency at high speed is increased slightly. The ratio of r.p.m. at climbing speed, V(sub c) , to the r.p.m. at maximum speed, V (sub m) is dependent upon the ratio of V(sub c) to V(sub m)."
Date: June 1931
Creator: Louden, F. A.
Partner: UNT Libraries Government Documents Department

Preliminary Tests of Blowers of Three Designs Operating in Conjunction with a Wing-Duct Cooling System for Radial Engines, Special Report

Description: "This paper is one of several dealing with methods intended to reduce the drag of present-day radial engine installations and improve the cooling at zero and low air speeds. The present paper describes model wind-tunnel tests of blowers of three designs tested in conjunction with a wing-nacelle combination. The principle of operation involved consists of drawing cooling air into ducts located in the wing root at the point of maximum slipstream velocity, passing the air through the engine baffles from rear to front, and exhausting the air through an annular slot located between the propeller and the engine with the aid of a blower mounted on the spinner" (p. 1).
Date: June 1939
Creator: Biermann, David & Valentine, E. Floyd
Partner: UNT Libraries Government Documents Department

Study of Turning Performance of a Fighter-Type Airplane Particularly as Affected by Flaps and Increased Supercharging, Special Report

Description: "Results of a study to determine the effects on turning performance due to various assumed modifications to a typical Naval fighter airplane are presented. The modifications considered included flaps of various types, both part and full space, increased supercharging, and increased wing loading. The calculations indicated that near the low-speed end of the speed range, the turning performance, as defined by steady level turns at a given speed, would be improved to some extent by any of the flaps considered at altitudes up to about 25,000 feet" (p. 1).
Date: June 1942
Creator: Wetmore, J. W.
Partner: UNT Libraries Government Documents Department

Wind-Tunnel Tests of Several Model Tractor-Propeller and Pusher-Propeller Wing Extension-Shaft Arrangements, Special Report

Description: "Tests were made in the 20-foot propeller-research tunnel to investigate the possibility of obtaining increased net efficiencies of propeller-nacelle units by enclosing the engines in the wings and by using extension shafts. A wing of 5-foot chord was fitted with a propeller drive assembly providing for several axial locations of tractor propellers and pusher propellers. A three-blade 4-foot propeller and a three-blade 3 1/2-foot propeller of special design were tested in this wing with spinners and fairings ranging in diameter from 6 to 16 inches" (p. 1).
Date: June 1941
Creator: Harmon, Hubert N.
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" (p. 1).
Date: June 1939
Creator: Stack, John
Partner: UNT Libraries Government Documents Department

The Calculated Effect of Various Hydrodynamic and Aerodynamic Factors on the Take-Off of a Large Flying Boat

Description: Present designs for large flying boats are characterized by high wing loading, high aspect ratio, and low parasite drag. The high wing loading results in the universal use of flaps for reducing the takeoff and landing speeds. These factors have an effect on takeoff performance and influence to a certain extent the design of the hull. An investigation was made of the influence of various factors and design parameters on the takeoff performance of a hypothetical large flying boat by means of takeoff calculations.
Date: June 1939
Creator: Olson, R. E. & Allison, J. M.
Partner: UNT Libraries Government Documents Department

Effects of Direction of Propeller Rotation on the Longitudinal Stability of the 1/10-Scale Model of the North American XB-28 Airplane With Flaps Neutral

Description: "The effects of direction of propeller rotation on factors affecting the longitudinal stability of the XB-28 airplane were measured on a 1/10-scale model in the 7- by 10-foot tunnel of the Ames Aeronautical Laboratory. The main effect observed was that caused by regions of high downwash behind the nacelles (power off as well as power on with flaps neutral). The optimum direction of propeller rotation, both propellers rotating up toward the fuselage, shifted this region off the horizontal tail and thus removed its destabilizing effect" (p. 1).
Date: June 1942
Creator: Delany, Noel K.
Partner: UNT Libraries Government Documents Department

An Investigation of the Drag of Windshields in the 8-Foot High-Speed Wind Tunnel

Description: "The drag of closed-cockpit and transport-type windshields was determined from tests made at speeds from 200 to 440 miles per hour in the NACA 8-foot high-speed wind tunnel. This speed range corresponds to a test Reynolds number range of 2,510,000 to 4,830,000 based on the mean aerodynamic chord of the full-span model (17.29 inches). The shapes of the windshield proper, the hood, and the tail fairing were systematically varied to include common types and a refined design" (p. 1).
Date: June 1939
Creator: Robinson, Russell G. & Delano, James B.
Partner: UNT Libraries Government Documents Department