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Full-scale whirl impact tests simulating tree strikes and low-velocity wrench drop tests have been conducted on a full-scale graphite/glass-epoxy 11 ft dia. two-bladed tail rotor. Damage following whirl impact of 1 2 in and 1 in dia. hard maple wood dowels and a 1 1 4 in dia. maple tree branch was limited to the trip cap and tip balance weight retention bolts and was not sufficient to cause a mission abort. Low-velocity impact tests were performed by dropping a 1·6 lb wrench and a 1·9 lb steel projectile from a height of 12 ft on to various areas of the blade. The construction of the blade, which completely encases the graphite-epoxy spar with a glass-epoxy torque tube and aerodynamic shell, proved to be relatively invulnerable to this type of hazard.

This report identifies properties to be considered when selecting materials used in construction of torque tubes for rotating superconducting field windings in electrical machinery. The main design requirements are stated and the groups of material properties that influence directly the mechanical and thermal performance of a torque tube are derived. Most desirable is a low thermal conductivity to modulus of elasticity ratio which governs the refrigeration expenses and the tube wall aspect ratio (thickness/length). Numerical examples point out that fibre-reinforced plastics are potential candidates for use in torque tubes.

Ti-4A1-4Mo-2Sn-0.5Si was launched at a time when the use of titanium in gas-turbine engines and airframes was almost a novelty. In the intervening years the use of titanium alloys in the aerospace industry has grown enormously and much has been learned about their behaviour in critical structural applications. This is no less true for Ti-4A1-4Mo-2Sn-0.5Si and this paper details the mechanical properties of the alloy and examines some of the applications for it in current European aircraft projects.

Tests were conducted to evaluate the performance of a 10-in. flow controller in sodium at temperatures up to 1200 deg F. Torque tube reliability was determined by extensive mechanical cycling tests and further checking with a helium mass-spectrometer leak detector. Flow control performance and valve vibration characteristics were tested and evaluated and flow rate limits were established. The valve assembly was subjected to a thermal shock test program simulated to represent the most severe conditions likely to be encountered during a minimum l0-yr lifetime. (auth)