This paper gives some quantitative measurements of wind tunnel turbulence and its effect on the air resistance of spheres and airship models, measurements made possible by the hot wire anemometer and associated apparatus in its original form was described in Technical Report no. 320 and some modifications are presented in an appendix to the present paper. One important result of the investigation is a curve by means of which measurements of the air resistance of spheres can be interpreted to give the turbulence quantitatively. Another is the definite proof that the discrepancies in the results on the N. P. L. Standard airship models are due mainly to differences in the turbulences of the wind tunnels in which the tests were made.

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.

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.

This report describes the atmospheric conditions under which ice is formed upon the exposed parts of airplanes in flight. It identifies the formation found under different conditions, and describes some studies of preventative means.

Circular presenting a description of the K 47 airplane, which is a two-seat aircraft created by the A.B. Flygindustri in Sweden. A description of the construction, design, interior, performance, visibility, wings, fuselage, controls, landing gear, engines, weapons, characteristics, drawings, and photographs are provided.

Lautal is a refinable aluminum alloy which, unlike duralumin, contains no magnesium. According to the statements of the Lauta Works, lautal contains: aluminum, 94%; copper, 4%; silicon, 2%. The use of lautal as a construction material is discussed in relation to specific weight, production methods, and riveting tests.

Memorandum presenting a general overview of aircraft constructed from metal and fuselages constructed from strip metal.

Memorandum describing the use of wing spars in metal aircraft. An overview of different types of spurs and testing of the spurs in aircraft are provided.

Strip metal construction of wing spars are presented as well as workshop practices.

The Parnall Pipit is a single-seat ships fighter equipped with a Rolls Royce "F" type engine and armed with two synchronized Vickers guns. It can also be configured to carry bombs under the wings.

The air forces on a twenty-centimeter sphere were measured after it had been rebuilt as an open throat type. The results from tests made at widely different densities and airspeeds and also on a smaller sphere are given. The conclusions are that approximately the same drag coefficient is obtained at a given value of the Reynolds number irrespective of what combination of the variables is used to obtain that value and that the turbulence of the air stream at the test section, as measured by the critical Reynolds number of a sphere, is less for the new tunnel than for the old one.

"The flight path followed by an airplane which was being flown by a blindfolded pilot was observed and recorded. When the pilot attempted to make a straight-away flight there was a tendency to deviate from the straight path and to take up a spiral one" (p. 1).