This report presents the results of an investigation to determine the effect of different supercharger capacities on the performance of an airplane and its engine . The tests were conducted on a DH4-M2 airplane powered with a Liberty 12 engine. In this investigation four supercharger capacities, obtained by driving a roots type supercharger at 1.615, 1.957, 2.4, and 3 time engine speed, were used to maintain sea-level pressure at the carburetor to altitudes of 7,000, 11,500, 17,000, and 22,000 feet, respectively. The performance of the airplane in climb and in level flight was determined for each of the four supercharger drive ratios and for the unsupercharged condition.

"An adjustable blade metal propeller was tested at five different angle settings, forming a series varying in pitch. The propeller was mounted on a VE-7 airplane in the twenty-foot propeller research tunnel of the National Advisory Committee for Aeronautics. The efficiencies were found to be from 4 to 7 per cent higher than those of standard wood propellers operating under the same conditions. The results are given in convenient form for use in selecting propellers for aircraft" (p. 521).

Scientific paper issued by the Bureau of Standards over thermal expansion of fused silica. As stated in the abstract, "this paper gives the results of an investigation on the thermal expansion of transparent and nontransparent fused silica for various temperature ranges between -125 and +1,000 degrees Celsius. A detailed description of the apparatus and the methods used in this research and a summary of available data obtained by previous observers on the thermal expansion of fused silica are given" (p. 1). This paper includes tables, photographs, and illustrations.

Technical paper issued by the Bureau of Standards over studies conducted on fire-clay bricks. The results of the studies are discussed. This paper includes tables, and illustrations.

Report discusses the results of testing on a B.M.W. engine in an altitude chamber where temperature and pressure can be controlled to simulate flight at various altitudes. Results for various engine speeds, altitudes, and propeller speeds are provided.