Technical Report Archive and Image Library (TRAIL) - Browse

ABOUT BROWSE FEED

Propeller design I : practical application of the blade element theory

Description: This report is the first of a series of four on propeller design and contains a description of the blade elements or modified Drzewiecke theory as used in the Bureau of Aeronautics, U.S. Navy Department. Blade interference corrections are used which were taken from R.& M. NO. 639 of the British Advisory Committee for Aeronautics. The airfoil characteristics used were obtained from tests of model propellers, not from tests of model wings.
Date: May 1, 1926
Creator: Weick, Fred E.
Partner: UNT Libraries Government Documents Department

Propeller design IV : a simple method for determining the strength of propellers

Description: The object of this report, the last of a series of four on propeller design, is to describe a simple method for determining whether the strength of a propeller of a standard form is sufficient for safe operation. An approximate method of stress analysis is also given.
Date: June 1, 1926
Creator: Weick, Fred E.
Partner: UNT Libraries Government Documents Department

Propeller-Design Problems of High-Speed Airplanes, Special Report

Description: It is shown that on the basis of existing high-speed airfoil data, propeller efficiencies appreciably in excess of 40% do not appear possible at speeds above 500 miles per hour at 20,000 feet. The assumption that present propeller-blade thicknesses cannot be reduced radically, is implied. Until the reliability and applicability of the airfoil data are established, this conclusion must not be regarded as infallible. Dive tests with airplanes equipped with thrust meters and torque meters are proposed to provide an urgently needed check. The design of high-speed propellers is dictated wholly by compressibility considerations. The blade width, thickness, and pitch distribution; also the airfoil sections, the lift coefficient, the propeller diameter, and rpm must all be adjusted if reasonable efficiencies are to be maintained at airplane speeds that are now being approached. Research is urgently needed on: 1) airfoils at subsonic, sonic, and supersonic speeds; 2) propellers at high forward speeds in wind tunnels; 3)propellers in free flight at high speeds; and 4) jet propulsion and related devices. The breakdown of propeller efficiency indicated by airfoil data, should serve as an incentive for accelerated research on jet propulsion. This device may extend the attainable speed of current airplanes to the neighborhood of 550 miles per hour at 20,000 feet.
Date: April 1, 1941
Creator: Dickinson, H. B.
Partner: UNT Libraries Government Documents Department

Propeller induced angles of attack and section angles of attack for the NACA 10-(3)(066)-03, 10-(3)(049)-03, 10-(3)(090)-03, 10-(5)(066)-03, and 10-(0)(066)-03 propellers

Description: This paper presents the results of an induced angle-of-attack calculation using a method applicable to a propeller with arbitrary circulation distribution. Tables of induced angles of attack and section angles of attack and curves of wake-survey results are presented for the NACA 10-(3)(066)-03, 10-(3)(049)-03, 10-(3)(090)-03, 10-(5)(066)-03, and 10-(0)(066)-03 propellers. A brief description of the method of calculating propeller induced angles of attack is given.
Date: May 7, 1952
Creator: Igoe, William, B & Davidson, Robert E
Partner: UNT Libraries Government Documents Department

Propeller-performance charts for transport airplanes

Description: The preliminary selection of a propeller on the basis of cruising and take-off performance for application to transport airplanes at flight Mach numbers up to 0.8 can be accomplished by the use of charts and methods presented. The charts are of sufficient scope to permit a fairly rapid evaluation of the propeller performance for engine power ratings of 1,000 to 10,000 horsepower. The method is presented primarily in the interest of propeller-noise abatement.
Date: July 1, 1953
Creator: Gilman, Jean, Jr
Partner: UNT Libraries Government Documents Department

Propeller problems

Description: This report tries to give a comprehensive survey of the most important propeller problems such as the shape of propellers and the effect of atmospheric conditions on propeller performance.
Date: December 1, 1928
Creator: Betz, A.
Partner: UNT Libraries Government Documents Department

Propeller rotation noise due to torque and thrust

Description: Sound pressure of the first four harmonics of rotation from a full-scale two-blade propeller were measured and are compared with values calculated from theory. The comparison is made (1) for the space distribution with constant tip speed and (2) for fixed space angles with variable tip speed. A relation for rotation noise from an element of radius developed by Gutin is given showing the effect of number of blades on the rotation noise.
Date: January 1, 1940
Creator: Deming, Arthur F
Partner: UNT Libraries Government Documents Department

Propeller scale effect and body interference

Description: This note shows that the main part of the discrepancy between full flight propeller performance and the performance of models in a wind tunnel is due to a scale effect, and that a minor part is caused by body interference. Analyses are made of propeller performances on several standard airplanes, and the actual brake horsepower compared with the power as calculated from model test data. The calculated power is based on that absorbed by a wind tunnel propeller model which is geometrically similar to the full scale propeller and is operating under the same ratio of V/nD.
Date: September 1, 1925
Creator: Weick, Fred E.
Partner: UNT Libraries Government Documents Department

Propeller tests on airplanes

Description: In order to determine the efficiency of a propeller as accurately as possible, its revolution speed, thrust and power absorbed must be measured during flight. Unfortunately, these measurements can only be made with very complicated equipment. To surmount this problem the testers contented themselves with approximate results obtainable in two or three hours of flight.
Date: July 1, 1922
Creator: Senouque, A
Partner: UNT Libraries Government Documents Department

Propeller tests to determine the effect of number of blades at two typical solidities

Description: Propellers with equal total blade area, but with different numbers, were tested at Stanford University. The tests show generally that, for equal total blade area, propellers with the larger number of blades absorb the greater power and, provided hubs have equal drag, develop the higher efficiency. It is shown that the differences found are in agreement, qualitatively, with what might be predicted from simple blade-element theory.
Date: April 1, 1939
Creator: Lesley, E. P.
Partner: UNT Libraries Government Documents Department

Propeller theory of Professor Joukowski and his pupils

Description: This report gives a summary of the work done in Russia from 1911 to 1914, by Professor Joukowski and his pupils. This summary will show that these men were the true originators of the theory, which combines the theory of the wing element and of the slipstream.
Date: April 1, 1922
Creator: Margoulis, W
Partner: UNT Libraries Government Documents Department

Propeller tip flutter

Description: The present report is limited to a case of tip flutter recognized by experience as being important. It is the case where outside interferences force vibrations upon the propeller. Such interferences may be set up by the engine, or they may be the result of an unsymmetrical field of flow.
Date: September 1, 1932
Creator: Liebers, Fritz
Partner: UNT Libraries Government Documents Department

Propellers in yaw

Description: It was realized as early as 1909 that a propeller in yaw develops a side force like that of a fin. In 1917, R. G. Harris expressed this force in terms of the torque coefficient for the unyawed propeller. Of several attempts to express the side force directly in terms of the shape of the blades, however, none has been completely satisfactory. An analysis that incorporates induction effects not adequately covered in previous work and that gives good agreement with experiment over a wide range of operating conditions is presented. The present analysis shows that the fin analogy may be extended to the form of the side-force expression and that the effective fin area may be taken as the projected side area of the propeller.
Date: January 1, 1945
Creator: Ribner, Herbert S
Partner: UNT Libraries Government Documents Department

The proper combination of lift loadings for least drag on a supersonic wing

Description: Lagrange's method of undetermined multipliers is applied to the problem of properly combining lift loadings for the least drag at a given lift on supersonic wings. The method shows the interference drag between the optimum loading and any loading at the same lift coefficient to be constant. This is an integral form of the criterion established by Robert T. Jones for optimum loadings. The best combination of four loadings on a delta wing with subsonic leading edges is calculated as a numerical example. The loadings considered have finite pressures everywhere on the plan form. Through the sweepback range the optimum combination of the four nonsingular loadings has about the same drag coefficient as a flat plate with leading-edge thrust.
Date: January 1, 1956
Creator: Grant, Frederick C
Partner: UNT Libraries Government Documents Department