National Advisory Committee for Aeronautics (NACA) - 5 Matching Results

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The friction of piston rings

Description: The coefficient of friction between piston ring and cylinder liner was measured in relation to gliding acceleration, pressure, temperature, quantity of oil and quality of oil. Comparing former lubrication-technical tests, conclusions were drawn as to the state of friction. The coefficients of friction as figured out according to the hydrodynamic theory were compared with those measured by tests. Special tests were made on "oiliness." The highest permissible pressure was measured and the ratio of pressure discussed.
Date: March 1, 1945
Creator: Tischbein, Hans W
Partner: UNT Libraries Government Documents Department

The Minimum Energy Loss Propeller

Description: Various cases are presented of the solution of the problem ot the most efficient propeller, more general cases being considered than the one by Betz in 1919: namely, that of a propeller under a limiting light load, The problem is solved directly and also with the aid of the Ritz method which became readily applicable after the author proposed a method for the solution of the propeller problem, in general, with the aid of trigonometric series. The design of a propeller with the aid of this method is given and an analysis is made of the effect of the fuselage and of the viscosity coefficient mu on the character of the solution of the variational problem.
Date: March 1, 1945
Creator: Poliakhov, N.
Partner: UNT Libraries Government Documents Department

New Method of Determining the Polar Curve of an Airplane in Flight

Description: A fundamental defect of existing methods for the determination of the polar of an airplane in flight is the impossibility of obtaining the thrust or the resistance of the propeller for any type airplane with any type engine. The new method is based on the premise that for zero propeller thrust the mean angle of attack of the blade is approximately the same for all propellers if this angle is reckoned from the aerodynamic chord of the profile section. This angle was determined from flight tests. Knowing the mean angle of the blade setting the angle of attack of the propeller blade at zero thrust can be found and the propeller speed in gliding obtained. The experimental check of the new method carried out on several airplanes gave positive results. The basic assumptions for the construction of the polars and the method of analyzing the flight data are given.
Date: March 1, 1945
Creator: Yegorov, B. N.
Partner: UNT Libraries Government Documents Department