From Summary: "This report presents, further, information on the properties of various other native species of wood compared with spruce, and discusses the characteristics of a considerable number of them from the standpoint of their possible application in aircraft manufacture to supplement the woods that are now most commonly used."

We first undertook experiments with air, devoted principally to the investigation of the disturbances due to the differences in the nature of the flow to the nozzle. The difficulty of measuring the air, however, caused us to experiment with water. Due to the possibility of measuring the capacity of the container, this method was much more accurate than measuring with Pitot tobes.

This report groups in a uniform manner the aerodynamic properties of commonly used wing sections as determined from tests in various wind tunnels. The data have been collected from reports of a number of laboratories. Where necessary, transformation has been made to the absolute system of coefficients and tunnel wall interference corrections have been applied. Tables and graphs present the data in the various forms useful to the engineer in the selection of a wing section.

This report provides a summary of the important steps to be taken in combating airplane fires. Some considerations and ways of preventing fires from developing are provided.

In the present study it is proposed to provide an equipment permitting the study of the propagation of the region of reaction in mixtures of air and carbureted gases enclosed within a cylinder. Ignition is produced at the end of compression by an electric spark. With this apparatus it is proposed to determine: 1) the influence of the richness of the explosive mixture on the rate of flame propagation; 2) the influence of the degree of volumetric compression on one of the hydrocarbons; 3) the influence of the variation of initial temperature of the mixture before compression; 4) the influence of tetraethyl-lead on the propagation - notably on the formation of the explosive wave.

Memorandum presenting the experimental results of tests to confirm the contribution to the study of normal burning in gaseous carbureted mixtures.

From Summary: "The tests described in this report furnished data on the actual aerodynamic forces, and the resulting stresses and bending moments in the hull of the U. S. S. "Los Angeles" during as severe still-air maneuvers as the airship would normally be subjected to, and in straight flight during as rough air as is likely to occur in service, short of squall or storm conditions. The maximum stresses were found to be within the limits provided for in accepted practice in airship design. Normal flight in rough air was shown to produce forces and stresses about twice as great as the most severe still-air maneuvers."

The object was to evaluate the factors which control the rate of heat transfer to a moving current of air from finned metal surfaces similar to those used on aircraft engine cylinders. This was to establish data which will enable the finning of cooling surfaces to be designed to suit the particular needs of any specific application. Most of the work was done on flat copper specimens 6 inches square, upon which were mounted copper fins with spacings varying from 1/2 inch to 1/12 inch. All fins were 1 inch deep, 6 inches long, and .020 inch thick. The results of the investigation are given in the form of curves included here.

Memorandum presenting a description of the Dornier seaplane Do X. Details of the general description, materials, details of the main wing and upper wing, details of the hull and of the wing stubs, tail surfaces and control lines, power plant, and launching car and floating dock are provided.

Circular presenting a description of the Weymann-Lepère W.E.L. 10. Some of the characteristics described include the principles of the construction, aerodynamics, descriptions of the components, flight characteristics, and photographs and blueprints.

"The purpose of this investigation was to obtain information for use in the design of truss and plywood forms, particularly with reference to wing ribs. Tests were made on many designs of wing ribs, comparing different types in various sizes. Many tests were also made on parallel-chord specimens of truss and plywood forms in place of the actual ribs and on parts of wing ribs, such as truss diagonals and sections of cap strips" (p. 223).

Report presents the results of wind tunnel tests of pressure distribution measurements over one section each of six airfoils. Pressure distribution diagrams, as well as the integrated characteristics of the airfoils, are given for both a high and a low dynamic scale or, Reynolds number VL/V, for comparison with flight and other wind-tunnel tests, respectively. It is concluded that the scale effect is very important only at angles of attack near the burble.

The revised report includes the chart for the analysis of aircraft accidents, combining consideration of the immediate causes, underlying causes, and results of accidents, as prepared by the special committee, with a number of the definitions clarified. A brief statement of the organization and work of the special committee and of the Committee on Aircraft Accidents; and statistical tables giving a comparison of the types of accidents and causes of accidents in the military services on the one hand and in civil aviation on the other, together with explanations of some of the important differences noted in these tables.

A complete technical description of the Clerget heavy-oil engine is presented along with the general characteristics. The general characteristics are: 9 cylinders, bore 120 mm, stroke 130 mm, four-stroke cycle engine, rated power limited to 100 hp at 1800 rpm; weight 228 kg; propeller with direct drive and air cooling. Moving parts, engine block, and lubrication are all presented.

Report issued by the U.S. Bureau of Mines on the coal mine related deaths during December, 1930. The number of fatalities and the causes are presented. This report includes tables.

This report deals with the effect of small variations in ordinates specified by different laboratories for the airfoil section. This study was made in connection with a more general investigation of the effect of small irregularities of the airfoil surface on the aerodynamic characteristics of an airfoil. These tests show that small changes in airfoil contours, resulting from variations in the specified ordinates, have a sufficiently large effect upon the airfoil characteristics to justify the taking of great care in the specification of ordinates for the construction of models.

Circular presenting a description of the Focke-Wulf F 19a "Ente" aircraft, which includes the unique design feature of the horizontal control surfaces being placed at the forward end of the fuselage while the wing is farther aft. Details of the design, aerodynamic characteristics, wings, controls, landing gear, power plant, fuel tanks, characteristics, drawings, and photographs are provided.

Circular presenting a description of the Hanriot H 431, which was designed to meet the requirements of the French War Ministry for general purpose airplanes. Details are provided for the design, flying qualities, and improvements over other aircraft designs.

From Summary: "The results of flight tests conducted by the NACA to determine the lift and drag characteristics of a full-scale airplane are given herein. A Fairchild FC-2W2 cabin monoplane having a Gottingen 387 wing section was used for the tests. The maximum lift coefficient for the airplane is compared with that obtained for the Gottingen 387 airfoil in recent tests in the Variable Density Tunnel. The maximum lift coefficient for the airplane was found to be 1.50 and that for the airfoil 1.56. Although the flight tests were confined chiefly to glides with the propeller locked horizontally, data obtained with the propeller operating at zero thrust for a few angles of attack are also included."

Report issued by the U.S. Bureau of Mines discussing dredging methods of used by the Ohio River Sand Company. The different methods and costs used to recover gravel and sand are described. This report includes tables and illustrations.

This note presents the results obtained in pressure distribution tests on the right upper panel of a Douglas M-3 airplane in flight. These tests are a part of an extensive investigation on the effect of changes in tip shape on the load distribution.

It was learned that the law of resistance for high R values does not follow the simple powers, and that the powers, which can be obtained approximately for the velocity distribution, gradually change. Since, moreover, very important investigations have recently been made on the resistance of plates at very high R values, it seemed of interest to apply the above line of reasoning to the new general law of resistance. For this purpose, the resistance and velocity distribution along the plate must always be equal to the values of the pipe flow at the corresponding Reynolds number.

An analysis is made here of the problem of long plates with transverse stiffeners subject to shear. A typical example would be a long Wagner beam. The shear stress is calculated at which the web wrinkles and shear stress becomes a maximum. The equation is solved for both a condition of free support and rigidity of support on the edges.

This report covers a series of tests on thin flat elastic strips restrained at two parallel edges and subjected to shear by conversely directed stresses. Theoretical treatments, particularly those of Lilly, Southwell and Skan, and Timoshenko are briefly outlined. The problem to be solved by these tests was to find out whether, and to what extent the conditions and assumptions upon which the calculations are based are complied with in the tests.