An investigation of overheating HS-31 alloy to temperatures of 1,650 degrees, 1,800 degrees, 1,900 degrees, and 2,000 degrees F during the course of rupture tests 1,500 degrees F was carried out. The overheating was applied periodically for 2 minutes in most of the tests. The intent was to develop basic information on the effect of overheats on creep- rapture properties in order to assist in the evaluation of damage from overheats during gas- turbine operation.

A series of test flights was conducted by the U. S. Navy over a 3-year period to evaluate the effects of icing on the operation of the ZFG-2 airship. In supercooled clouds, ice formed only on the forward edges of small protuberances and wires and presented no serious hazard to operation. Ice secretions of the glaze type which occurred in conditions described as freezing drizzle adversely affected various components to a somewhat greater extent. The results indicated a need for protection of certain components such as antennas, propellers, ad certain parts of the control system.