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Aerodynamic theory and tests of strut forms. Part II

Description: This report presents the second of two studies under the same title. In this part five theoretical struts are developed from distributed sources and sinks and constructed for pressure and resistance tests in a wind tunnel. The surface pressures for symmetrical inviscid flow are computed for each strut from theory and compared with those found by experiment. The theoretical and experimental pressures are found to agree quantitatively near the bow, only qualitatively over the suction range, the experimental suctions being uniformly a little low, and not at all near the stern. This study is the strut sequel to Fuhrmann's research on airship forms, the one being a study in two dimensions, the other in three. A comparison of results indicates that the agreement between theory and experiment is somewhat better for bodies of revolution than for cylinders when both are shaped for slight resistance. The consistent deficiency of the experimental suctions which is found in the case of struts was not found in the case of airships, for which the experimental suctions were sometimes above sometimes below their theoretical values.
Date: May 1929
Creator: Smith, R H
Item Type: Report

Aircraft accidents : method of analysis

Description: This report on a method of analysis of aircraft accidents has been prepared by a special committee on the nomenclature, subdivision, and classification of aircraft accidents organized by the National Advisory Committee for Aeronautics in response to a request dated February 18, 1928, from the Air Coordination Committee consisting of the Assistant Secretaries for Aeronautics in the Departments of War, Navy, and Commerce. The work was undertaken in recognition of the difficulty of drawing correct conclusions from efforts to analyze and compare reports of aircraft accidents prepared by different organizations using different classifications and definitions. The air coordination committee's request was made "in order that practices used may henceforth conform to a standard and be universally comparable." the purpose of the special committee therefore was to prepare a basis for the classification and comparison of aircraft accidents, both civil and military. (author).
Date: January 1, 1929
Item Type: Report

Airplane drag

Description: It has been less well understood that the induced drag (or, better said, the undesired increase in the induced drag as compared with the theoretical minimum calculated by Prandtl) plays a decisive role in the process of taking off and therefore in the requisite engine power. This paper seeks to clarify the induced drag.
Date: December 1929
Creator: Topfer, Carl
Item Type: Report

The Analysis of Aircraft Structures as Space Frameworks. Method Based on the Forces in the Longitudinal Members

Description: The following examples do not take up the discussion of viewpoints to be heeded in determining the design of a framework for given external conditions. Rather they are methods for determining the forces in airplane fuselages and wings, though similar considerations are applied to certain simple cases of a different kind. The object of this treatise is to summarize and amplify these considerations from definite viewpoints.
Date: July 1, 1929
Creator: Wagner, Herbert
Item Type: Report

The balance of moments and the static longitudinal stability of airplanes

Description: A nomogram is developed which renders it possible by drawing a few lines, to determine: the location of the center of gravity for zero wing and tail moments; the longitudinal dihedral angle; the tail coefficient F(sub h) iota/F(sub t). Moreover there is no difficulty in determining the magnitude of the restoring moment or of the unstable moment.
Date: December 1, 1929
Creator: Muller, Horst
Item Type: Report

Bauxite: Float-and-Sink Fractionations and Flotation Experiments

Description: From Introduction: "This report presents the results of an investigation of the physical properties and characteristics of bauxite, with special reference to the possibility of applying commercial methods of concentration to low-grade bauxite."
Date: 1929
Creator: Gandrud, B. W. & De Vaney, Fred D.
Item Type: Report

Beautifying the Farmstead

Description: Revised edition. Report giving practical ways for families to beautify farmsteads. Contains sections on design, locations of buildings, walkways, driveways, lawns, trees and other plants.
Date: 1929
Creator: Mulford, Furman Lloyd, b. 1869
Item Type: Pamphlet

Bibliography of Petroleum and Allied Substances, 1922 and 1923

Description: From Introduction: "This bulletin is the seventh in this series of petroleum bibliographies published by the Bureau of Mines, Bulletins 149, 165, 180, 189, 216, and 220 being complications for the years 1915, 1916, 1917, 1918, 1919-20, and 1921, respectively. In this bulletin the same general plan of classification of references has been followed, but several additions have been made."
Date: 1929
Creator: Britton, H.
Item Type: Report

Breeds of Sheep for the Farm

Description: Revised edition. Report discussing the different breeds of sheep raised by farmers and their suitability for either wool or mutton.
Date: 1929
Creator: Marshall, F. R.
Item Type: Pamphlet

Buckling tests of light-metal tubes

Description: I will attempt to determine mathematically the buckling-strength curves of various centrally loaded light-metal tubes which exhibit conspicuous differences of behavior under compressive loads. For this purpose I will employ Von Karman's method, after adapting it to special conditions.
Date: August 1, 1929
Creator: Schroeder, August
Item Type: Report

Calculation of the pressures on aircraft engine bearings

Description: For aircraft engines the three principal operating conditions are idling speed, cruising speed, and diving with the engine stopped. In what follows, we will discuss a method which affords a good idea of the course of pressure for the above mentioned operating conditions. The pressures produced in the driving gear are of three kinds; namely, the pressure due to gases, the pressure due to the inertia of the rotating masses, and the pressure due to the inertia of the reciprocating masses.
Date: December 1, 1929
Creator: Steigenberger, O
Item Type: Report

Cantilever Wings for Modern Aircraft: Some Aspects of Cantilever Wing Construction with Special Reference to Weight and Torsional Stiffness

Description: In the foregoing remarks I have made an attempt to touch on some of the structural problems met with in cantilever wings, and dealt rather fully with a certain type of single-spar construction. The experimental test wing was a first attempt to demonstrate the principles of this departure from orthodox methods. The result was a wing both torsionally stiff and of light weight - lighter than a corresponding biplane construction.
Date: November 1, 1929
Creator: Stieger, H. J.
Item Type: Report