Report discussing tires, steel springs, hydraulic shock absorbers, and axle travel are all examined in relation to absorbing landing shocks.

The technical staff of the NACA at Langley Field, has made a series of free flight tests with a JN4h airplane in order to find the best place for an instrument for measuring the angle of attack. A "neutral zone" was found where the air remains either at rest relative to the undisturbed air beyond the influence of the airplane, or is set in motion parallel to the motion of the airplane. This zone is about midway between the two wings and slightly in front of, or at the vertical plane through the leading edges of the wings but the exact position as well as the outlines of the zone varies considerably as the conditions of flight change.

From Introduction Purpose and Organization: "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 "Bulletin Technique", of March, 1919, gave the results of tests and studies made up to that date in connection with airplane parachutes. This work has been continued.

Describes the utility of multi-engine aircraft with special regard to the Argosy, which will seat up to 20 passengers and who's engines turn out nearly 1200 HP. The Argosy had a top speed of 110 MPH, and a range of 400 miles.

This report is a comprehensive study of birds and how their shapes have been molded by the resistance of the air. 500 species of birds were studied and nearly 30,000 ratios calculated. The author makes a distinction between flapping and soaring flight.

The Boeing Mail Airplane is a biplane with cloth covered wings of wood and wire construction, a top speed of 130 MPH, and a fuel capacity of 100 gallons in two tanks.

Report presenting an 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, Von Karman's method is used after adapting it to special conditions.

A simplified formula for calculating wing spars is presented.

The author presents a comparison and combination of the numerical and geometrical determinations of the maximum M, when calculating the maximum bay moment.

The author presents a comparison and combination of the numerical and geometrical determinations of the maximum M, when calculating the maximum bay moment.

From introduction: The production of gypsum is one of the oldest industries in Canada, and in point of gypsum output Canada ranks third among the countries of the world. Gypsum was discovered in the Maritime Provinces at a very early date, but there is no authentic record..of production until about 1822, when gypsum was mined on a small scale in Ontario. Since.then the production has grown slowly but steadily to more than a million tons. In 1928 the output was 1,205,846 short tons, valued at $3,622,007.

The Caproni 73 is a biplane with medium thick wings, a rigid central section, and with each lateral extension forming a single cell and is powered by two 500 Isotta Fraschini "Asso" Engines.

This report tries to solve the problem of supplying the engine cylinders with a mixture of fuel and air in the right ratio to obtain the greatest power from the engine with the least consumption of fuel.

The data obtained on the NACA M-12 airfoil, tested at twenty atmosphere density in the NACA variable density wind tunnel, have been extended by additional tests at one and at twenty atmospheres under improved conditions. The results of these tests are given. Considerable scale effect was found.

The difference between aircraft for commercial and wartime uses is delineated, but the interchangability between the two is also discussed. Airships in both roles are also presented.

In this work I have attempted to find a basis for the design of fuel cams, which will serve equally for large and small engines, both high-speed and low-speed.

Scientific paper issued by the Bureau of Standards over studies conducted on radio fading. As stated in the abstract, "the series of measurements on fading were devoted to studies of fading effects during the sunset period, effects during the solar eclipse of January 24, the fading variations throughout a 24-hour day, and the effects of high transmitting power on fading" (p. 419). This paper includes tables, maps, illustrations, and photographs.

"The Coutinho-Sacadura course corrector is an instrument with which, knowing the angles of drift of two different courses, we may determine by simple readings: a) direction and velocity of wind; b) correction to be made in course followed by compass, in order to fly in a given direction; c) ground-speed of aircraft, the resultant of its air speed and the velocity of the wind" (p. 1).

The wing strain meter enables a pilot to know the strain on lifting surfaces and to warn him of the safe limits which may not be exceeded. In wing strain the most important factors are the force of gravity and the force of lift which gives the measure of the sustaining force, and their components which are perpendicular to the lifting surfaces. This reports methods for using the wing strain meter.

Experimental data, such as the results of tank tests of models, render it possible to predict, at least in principle, as to how a hull or float of a given shape will comport itself. We will see further along, however, how uncertain these methods are and how they leave room for empiricism, which will reign for a long time yet in seaplane research bureaus.

Flight tests to determine lift and drag characteristics are discussed. A review is given of the fundamental principles on which the tests are based and on the forces acting on an airplane in the various conditions of steady flight. Glide with and without propeller thrust and the relation between angle of attack and the indicated airspeed for different conditions of steady flight are discussed. The glide test procedure and the problem of the propeller are discussed.

The results of the velocity measurements in the boundary layer described in NACA-TM 411 are here discussed in greater detail. The measurements made were of the velocity distribution in the vicinity of an airfoil model fitted with a rotary cylinder and were undertaken for the purpose of obtaining a closer insight into the phenomena observed in experimenting with this model.

"It is now well known that all nonrigid airships constructed at the present time have bow stiffeners consisting of battens curved to the form of the envelope and designed to hold the nose of the ship in its true form despite the very large pressure which exists at the extreme forward point. The effect of the stiffeners is to reduce considerably the apparent pressure which has to be maintained inside the envelope in order to prevent the nose from caving in" (p. 1).