National Advisory Committee for Aeronautics (NACA) - 13,806 Matching Results

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Variation with Mach Number of Static and Total Pressures Through Various Screens

Description: Tests were conducted in the Langley 24-inch highspeed tunnel to ascertain the static-pressure and total-pressure losses through screens ranging in mesh from 3 to 12 wires per inch and in wire diameter from 0.023 to 0.041 inch. Data were obtained from a Mach number of approximately 0.20 up to the maximum (choking) Mach number obtainable for each screen. The results of this investigation indicate that the pressure losses increase with increasing Mach number until the choking Mach number, which can be computed, is reached. Since choking imposes a restriction on the mass rate of flow and maximum losses are incurred at this condition, great care must be taken in selecting the screen mesh and wire dimmeter for an installation so that the choking Mach number is.
Date: February 1, 1946
Creator: Adler, Alfred A
Partner: UNT Libraries Government Documents Department

The Magnus effect in theory and in reality

Description: A discussion of the Flettner rotor is presented from a nautical and economic viewpoint, and although it was a failure, the experimental and theoretical inventions cannot be disregarded. The following critical and experimental investigation will show the relations and applicability of the theories and practical applications. The Magnus effect is described in detail and a discussion and critical review of the Magnus effect is included.
Date: May 1, 1930
Creator: Ahlborn, F
Partner: UNT Libraries Government Documents Department

Turbulence and mechanism of resistance on spheres and cylinders

Description: The nature of turbulent flow through pipes and around obstacles is analyzed and illustrated by photographs of turbulence on screens and straighteners. It is shown that the reversal of flow and of the resistance law on spheres is not explainable by Prandtl's turbulence in the boundary layer. The investigation of the analogous phenomena on the cylinder yields a reversal of the total field of flow. The very pronounced changes in pressure distribution connected with it were affirmed by manometric measurements on spheres by Professor O. Krell. The reversal in a homogenous nonvortical flow is brought about by the advance of the stable arrangement of Karman's dead air vortices toward the test object and by the substitution of an alternatingly one-sided or rotating but stable vortex formation in place of the initially symmetrical formation. This also explains the marked variations of the models.
Date: January 1932
Creator: Ahlborn, FR
Partner: UNT Libraries Government Documents Department

Analysis of the horizontal-tail loads measured in flight on a multiengine jet bomber

Description: From Introduction: "The primary objectives of the present paper are to report the horizontal-tail-loads measurements for configuration B which have not previously been reported and to summarize the horizontal-tail-loads results obtained with both configurations. The manner in which the aerodynamic-loads data were analyzed to include structural temperature effects and fuselage flexibility effects constitutes an important part of the present paper. "
Date: September 1955
Creator: Aiken, William S & Wiener, Bernard
Partner: UNT Libraries Government Documents Department

Analysis of horizontal-tail loads in pitching maneuvers on a flexible swept-wing jet bomber

Description: From Introduction: "The analysis of flight data in the present report is, to a large extent, based on analyses and information contained in references 1 and 2 for wing deflections, reference 3 for horizontal-tail parameters, reference 4 for airplane lift-curve slopes and angles of zero lift, and reference 5 for wing centers of pressure."
Date: December 1957
Creator: Aiken, William S , Jr
Partner: UNT Libraries Government Documents Department

Standard nomenclature for airspeeds with tables and charts for use in calculation of airspeed

Description: Symbols and definition of various airspeed terms that have been adopted as standard by the NACA subcommittee on aircraft structural design are presented. The equations, charts, and tables required in the evaluation of true airspeed, calibrated airspeed, equivalent airspeed, impact and dynamic pressures, and Mach and Reynolds numbers have been compiled. Tables of the standard atmosphere to an altitude of 65,000 feet and a tentative extension to an altitude of 100,000 feet are given along with the basic equations and constants on which both the standard atmosphere and the tentative extension are based.
Date: January 1, 1946
Creator: Aiken, William S , Jr
Partner: UNT Libraries Government Documents Department

Strain-Gage Measurements of Buffeting Loads on a Jet-Powered Bomber Airplane

Description: Buffet boundaries, buffeting-load increments for the stabilizers and elevators, and buffeting bending-moment increments for the stabilizers and wings as measured in gradual maneuvers for a jet-powered bomber airplane are presented. The buffeting-load increments were determined from strain-gage measurements at the roots or hinge supports of the various surfaces considered. The Mach numbers of the tests ranged from 0.19 to 0.78 at altitudes close to 30,000 feet. The predominant buffet frequencies were close to the natural frequencies of the structural components. The buffeting-load data, when extrapolated to low-altitude conditions, indicated loads on the elevators and stabilizers near the design limit loads. When the airplane was held in buffeting, the load increments were larger than when recovery was made immediately.
Date: March 19, 1951
Creator: Aiken, William S., Jr. & See, John A.
Partner: UNT Libraries Government Documents Department

Extension of pack method for compressive tests

Description: The pack method for determining compressive stress-strain graphs described in NACA Report No. 649 has been modified to extend it's application to thinner gages and stronger materials. The principal modifications consisted in the provision of additional support against instability cementing the specimens of the pack together with fused shellac and the provision of special clamps to hold the specimens together while the test is in progress. The shellac was found to increase the buckling load of the pack without any appreciable effect on the compressive stress-strain graph of the material. The extended pack method described in this note has made possible the application of stresses in excess of 220 kips per square inch to sheet material having a thickness of only 0.02 inch.
Date: December 1, 1940
Creator: Aitchison, C S
Partner: UNT Libraries Government Documents Department

A subpress for compressive tests

Description: A subpress for compressive tests is described. The subpress was designed primarily for use in developing and investigating methods for testing thin sheet metal in compression. Provision was made for testing fixed-end and flat-end specimens with or without various types of lateral support against buckling. Compressive stress-strain data for a sheet of 0.032-inch 24S-RT aluminum alloy were obtained with the subpress by the pack method and by the single-thickness method. The data showed small scatter and the stress-strain curves obtained by the two methods were in close agreement.
Date: December 1, 1943
Creator: Aitchison, C S & Miller, James A
Partner: UNT Libraries Government Documents Department

The pack method for compressive tests of thin specimens of materials used in thin-wall structures

Description: The strength of modern lightweight thin-wall structures is generally limited by the strength of the compression members. An adequate design of these members requires a knowledge of the compressive stress-strain graph of the thin-wall material. The "pack" method was developed at the National Bureau of Standards with the support of the National Advisory Committee for Aeronautics to make possible a determination of compressive stress-strain graphs for such material. In the pack test an odd number of specimens are assembled into a relatively stable pack, like a "pack of cards." Additional lateral stability is obtained from lateral supports between the external sheet faces of the pack and outside reactions. The tests seems adequate for many problems in structural research.
Date: January 1, 1939
Creator: Aitchison, C S & Tuckerman, L B
Partner: UNT Libraries Government Documents Department