Bulletin presenting load-displacement curves for use in establishing allowable-load values for riveted joints assembled by an NACA flush-riveting procedure. Comparative data are also given to show the effect of variations in the procedure on the yield and maximum shear loads for the rivets.

Report discusses a proposal for propeller manufacturers to consider the side-force factor with the activity factor as a fundamental parameter for all blade designs and for the side-force factor to be included in all reports of powered models in wind tunnels. The proposal includes a method for calculating the side-force factor and how it can be used in propeller development. It is shown to be a good index of the relative effectiveness per blade of a yawed propeller in developing side force.

Report discusses the results of an investigation to study the effect of the height of a rivet head on the number of cycles required to cause failure of a machine-countersunk flush-riveted joint under a combined static and alternating shear load. A tight joint and a loose joint were tested and the number of cycles to failure and location of fatigue failure were compared.

Bulletin discusses a method to estimate aromatic hydrocarbons in hydrocarbon mixtures, which is important for determining the percentage of aromatics in fuel blends. The method was tested with nine base stocks at several levels of aromatics concentration and the maximum level of error was found to be about 0.5 percent. The speed and simplicity of the testing is emphasized.

Report discusses the results of tensile and compressive tests of two types of plastic-bonded glass cloth and their potential use in aircraft construction. The ultimate tensile stress and compressive yield stresses for the different materials are provided.