Note presenting a two part report on cylinder; one is on the modulus of electricity of celluloid sheet and the effect of temperature change on the value of the modulus of elasticity, while the other gives the results of tests on a considerable number of thin-walled, circular celluloid cylinders of several lengths, diameters, and wall thicknesses.

Note presenting an experimental determination of the apparent friction coefficient for the flow of air through smooth pipes at subsonic and supersonic velocities. In supersonic flow, the results were found to be strongly influenced by the presence of oblique shocks formed at the junction of nozzle and pipe. Results regarding the apparent friction coefficient, subsonic flow, supersonic flow, and comparisons with other investigations are provided.

Note presenting the necessary pressure and force coefficients acting on a thin airfoil with a flap and tab in a form suitable for stability calculations in order to design improved control arrangements.

Note presenting a determination of the bonding strengths of two thermosetting adhesives, liquid Cycleweld C-3 and Ardux 1, to several aircraft materials using shear tests made on lap-joint specimens. The specimens were tested at 25 degrees Celsius and at subfreezing temperatures of approximately -40 degrees Celsius. Results regarding the specimens bonded under clamping pressure, specimens bonded after various surface treatments, specimens of metal bonded to plywood, and specimens of aluminum bonded to magnesium are provided.

Note presenting an experimental investigation of the influences of blade shank form and pitch distribution on the aerodynamic characteristics of constant-speed propellers. The results indicated that the replacement of round blade shanks by faired ones produced substantial improvements of efficiency which increased with the advance ratio. Results regarding blade shank form, pitch distribution, and influences of blade loading and number of blades are provided.

Note presenting a study of the shear elastic properties of monel, nickel, Inconel, and aluminum-model tubing, as influenced by extension of annealed specimens, by cold reduction during manufacture, and by stress-relief annealing of cold-reduced materials. With slight extension of annealed tubing, the shear proof stresses generally decrease, owing to induced internal stress.

"There are several constants which have been devised as numerical representations of the behavior of metals under the action of loadings which stress the metal within the range of elastic action. Some of these constants, such as Young's modulus of elasticity in tension and compression, shearing modulus of elasticity, and Poisson's ratio, are regularly used in engineering calculations. Precise tests and experience indicate that these elastic constants are practically unaffected by many of the factors which influence the other mechanical properties of materials and that a few careful determinations under properly controlled conditions are more useful and reliable than many determinations made under less favorable conditions" (p. 1).