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  Partner: UNT Libraries Government Documents Department
 Collection: Technical Report Archive and Image Library
Flight Comparison of Performance and Cooling Characteristics of Exhaust-Ejector Installation with Exhaust-Collector-Ring Installation

Flight Comparison of Performance and Cooling Characteristics of Exhaust-Ejector Installation with Exhaust-Collector-Ring Installation

Date: February 14, 1947
Creator: Acker, Loren W. & Kleinknecht, Kenneth S.
Description: Flight and ground investigations have been made to compare an exhaust-ejector installation with a standard exhaust-collector-ring installation on air-cooled aircraft engines in a twin-engine airplane. The ground investigation allowed that, whereas the standard engine would have overheated above 600 horsepower, the engine with exhaust ejectors cooled at take-off operating conditions at zero ram. The exhaust ejectors provided as much cooling with cowl flaps closed as the conventional cowl flaps induced when full open at low airspeeds. The propulsive thrust of the exhaust-ejector installation was calculated to be slightly less than the thrust of the collector-ring-installation.
Contributing Partner: UNT Libraries Government Documents Department
Accelerations in fighter-airplane crashes

Accelerations in fighter-airplane crashes

Date: November 4, 1957
Creator: Acker, Loren W; Black, Duglad O & Moser, Jacob C
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Air forces on airfoils moving faster than sound

Air forces on airfoils moving faster than sound

Date: June 1, 1925
Creator: Ackeret, J
Description: We are undertaking the task of computing the air forces on a slightly cambered airfoil in the absence of friction and with an infinite aspect ratio. We also assume in advance that the leading edge is very sharp and that its tangent lies in the direction of motion.
Contributing Partner: UNT Libraries Government Documents Department
Drag measurements of two thin wing sections at different index values

Drag measurements of two thin wing sections at different index values

Date: June 1, 1927
Creator: Ackeret, J
Description: It is stated that the index value 6000, as found in normal tests of wing sections with a 20 cm chord, falls in the same region where the transition of laminar to turbulent flow takes place on thin flat plates. It is to be expected that slightly cambered, thin wing sections will behave similarly. The following test of two such wing sections were made for the purpose of verifying this supposition.
Contributing Partner: UNT Libraries Government Documents Department
Experiments on airfoils with trailing edge cut away

Experiments on airfoils with trailing edge cut away

Date: September 1, 1927
Creator: Ackeret, J
Description: Airfoils with their trailing edge cut away are often found on aircraft, as the fins on the hulls of flying boats and the central section of the wings for affording better visibility. It was therefore of some interest to discover the effect of such cutaways on the lift and drag and on the position of the center of pressure. For this purpose, systematic experiments were performed on two different airfoils, a symmetrical airfoil and an airfoil of medium thickness, with successive shortenings of their chords.
Contributing Partner: UNT Libraries Government Documents Department
High-speed wind tunnels

High-speed wind tunnels

Date: November 1, 1936
Creator: Ackeret, J
Description: Wind tunnel construction and design is discussed especially in relation to subsonic and supersonic speeds. Reynolds Numbers and the theory of compressible flows are also taken into consideration in designing new tunnels.
Contributing Partner: UNT Libraries Government Documents Department
Present and future problems of airplane propulsion

Present and future problems of airplane propulsion

Date: May 1, 1941
Creator: Ackeret, J
Description: Some of the problems considered in this report include: thermodynamics of surface friction, application of thick wing sections, special applications of controllable propellers, and gas turbines for aircraft.
Contributing Partner: UNT Libraries Government Documents Department
Recent experiments at the Gottingen Aerodynamic Institute

Recent experiments at the Gottingen Aerodynamic Institute

Date: July 1, 1925
Creator: Ackeret, J
Description: This report presents the results of various experiments carried out at the Gottingen Aerodynamic Institute. These include: experiments with Joukowski wing profiles; experiments on an airplane model with a built-in motor and functioning propeller; and the rotating cylinder (Magnus Effect).
Contributing Partner: UNT Libraries Government Documents Department
Removing boundary layer by suction

Removing boundary layer by suction

Date: January 1, 1927
Creator: Ackeret, J
Description: Through the utilization of the "Magnus effect" on the Flettner rotor ship, the attention of the public has been directed to the underlying physical principle. It has been found that the Prandtl boundary-layer theory furnishes a satisfactory explanation of the observed phenomena. The present article deals with the prevention of this separation or detachment of the flow by drawing the boundary layer into the inside of a body through a slot or slots in its surface.
Contributing Partner: UNT Libraries Government Documents Department
Experimental and Theoretical Investigations of Cavitation in Water

Experimental and Theoretical Investigations of Cavitation in Water

Date: May 1, 1945
Creator: Ackeret, J.
Description: The cavitation in nozzles on airfoils of various shape and on a sphere are experimentally investigated. The limits of cavitation and the extension of the zone of the bubbles in different stages of cavitation are photographically established. The pressure in the bubble area is constant and very low, jumping to high values at the end of the area. The analogy with the gas compression shock is adduced and discussed. The collapse of the bubbles under compression shock produces very high pressures internally, which must be contributory factors to corrosion. The pressure required for purely mechanical corrosion is also discussed.
Contributing Partner: UNT Libraries Government Documents Department