Circular presenting a description of the C.A.M.S. 60, which is a twin-engine monoplane with a medium-thickness wing and two floats. Details of the wings, engines, fuselages, floor, rear cabin, floats, and flying qualities are provided.

Circular describing the S.A.B.C.A. S.XI commercial airplane, which is a high-wing semicantilever monoplane. Details of the history of its creation, its design, components, engines, fuel tanks, characteristics, performances, drawings, and photographs are provided.

Circular describing the De Havilland Express Air Liner, which is a four-engine two-bay biplane of clean and well-streamlined form. Details of the cabin, controls, fuselage, tail, wings, engines, cockpit, characteristics, performance, drawings, and photographs are provided.

Circular describing the S.P.C.A. 40 T, which is a commercial all-metal cantilever airplane that was guided by the two essential requirements of economy and safety in its design. Details of the design, power, test results, fuel tanks, characteristics, performances, drawings, and photographs are provided.

Circular describing the Farman F.300 airplane, which is a high-wing semicantilever monoplane. Details of the wings, engine, equipment, safety, characteristics, performance, drawings, and photographs are provided.

Circular presenting a description of the Boulton and Paul P.64 high-performance mail-carrier. It is a two-engine tractor biplane that has been designed to give the specified normal speed with each engine throttled down to approximately half its output. Details of the landing gear, structural features, pilots' compartment, accommodation for mails, controls, power plant, and some flying qualities are provided.

Circular describing the Potez 39, which is an all-metal high-wing two-seat observation monoplane. Details regarding the design, construction, components, characteristics, drawings, and photographs are provided.

The object of the present study was to define experimentally the field of temperature and velocity in a heated flat plate when exposed to an air stream whose direction is parallel to it, then calculate therefrom the heat transference and the friction past the flat plate, and lastly, compare the test data with the mathematical theory. To ensure comparable results, we were to actually obtain or else approximate: a) two-dimensional flow; b) constant plate temperature in the direction of the stream. To approximate the flow in two dimensions, we chose a relatively wide plate and measured the velocity and temperature in the median plane.

The present report concerns the development of general propeller performance and r.p.m. curves which, combined with the general curve of the power required for level flight, presents a complete picture of the performance. The curve of power required for level flight in this paper is only an approximation for constant profile drag coefficient, meaning that it is not suitable to unconventional wing sections.

Circular presenting a description of the Caudron P.V. 200 touring amphibian, which is a two-place cantilever monoplane with folding wings and dual controls. Details of the wing, fuselage, controls, landing gear, flying qualities, and photographs are provided.

Circular describing the Ateliers des Mureaux 111 R.2 military airplane, which is a long-distance all-metal observation monoplane. A description of the design and construction, characteristics, flying qualities, drawings, and photographs are provided.

Report issued by the U.S. Bureau of Mines on the coal mine related deaths that occurred during the month of March, 1931. The number of fatalities and their causes are listed. This report includes tables.

This memorandum, constitutes a report on the results of experiments conducted at the U. S. Waterways Experiment Station on a small scale model of that reach of the Mississippi River near and including Dogtooth Bend (Mile 32.7 above to Mile 4.0 below Cairo).

Based upon Kirchoff's theory of free jets the flow through different screen arrangements of flat plates, as chiefly encountered with turbines in the cavitation zone is defined. It is shown by experiments that these theoretical results are very well representative in most cases of the conditions of discharge from water in air and consequently by cavitation. In addition, the experiments reveal a picture of the discrepancies between the actual flow and the theory of discharge of air in air (of water in water without cavitation).

"When an airplane describes a curve it takes a certain time for it to turn from level to inclined position and then back to level again. In the following, we express the motion about the horizontal axis as "roll" or "bank" and the motion perpendicular to the vertical axis, i.e., the actual curve, as "turn." Equations and tables provide results on various aspects of turns, control settings, acceleration, inertia moments, and angular velocity" (p. 2).

This investigation has a double object: 1) the calculation of the general characteristics of certain wings with progressively varying sections; 2) the determination of data furnishing, in certain cases, some information on the actual distribution of the external forces acting on a wing. We shall try to show certain advantages belonging to the few wing types of variable section which we shall study and that, even if the general aerodynamic coefficients of these wings are not often clearly superior to those of certain wings of uniform section, the wings of variable section nevertheless have certain advantages over those of uniform section in the distribution of the attainable stresses.

Progress in the scientific and practical fields of aviation has caused the Swiss Institute of Technology to organize lectures and practical training courses in all three branches of aeronautics and to found centers of scientific research, laboratories, etc., in order to supply the government and industries with scientifically and technically trained engineers.

Tailless airplanes are characterized by having all their control surfaces, especially the elevator, incorporated in the wings. This paper provides a discussion of the history of their development and current state of development.

Summary report outlining statistics and general information about the public utilities in Georgetown, Texas.

"This report gives the characteristics of a wing with an auxiliary airfoil mounted near its trailing edge and used as a flap. The tests were made with a 10 by 60 inch Clark Y main airfoil and an NACA 0012 flap having a chord equal to 15 percent of the main wing chord. The axis of the flap in all cases was on the flap chord and 20 percent back from its leading edge. The optimum location of the flap axis relative to the main wing for maximum lift was found to be 1.25 percent of the main wing chord behind the trailing edge and 2.5 percent below the chord" (p. 1).

"Methods of automatically controlling the airplane are reviewed. Equations for the controlled motion including inertia effects of the control are developed and methods of investigating the stability of the resulting fifth and higher order equations are presented. The equations for longitudinal and lateral motion with both ideal and non-ideal controls are developed in dimensionless form in terms of control parameters based on simple dynamic tests of the isolated control unit" (p. 1).

"Flow coefficients were determined for the inlet valve of a modern air-cooled cylinder during operation of the valve. The cylinder head with valves was mounted on a large tank that could be evacuated. Operating the valve with a rotating cam allowed air to flow through the valve into the evacuated tank. The change of pressure in the tank was a measure of the amount of air flowing though the valve in a given number of cycles. The flow coefficients were determined from the pressure across the valve, the quantity of air flowing, and the valve-lift curve" (p. 1).

Note presenting tests of several forms of fixed wing slot in a large-chord NACA 23012 airfoil in the closed-throat 7- by 10-foot wind tunnel. The airfoil extended completely across the test section so that two-dimensional flow was approximated. The data are presented in the form of tables of important aerodynamic characteristics for each slot tested and as curves of section lift, profile-drag, and pitching-moment coefficients.

"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" (p. 1).