Development of Size 22 Type D.50.S Silicon-Magnesium-Aluminium Alloy Aircraft Cables and Terminations

摘要

The Report assesses the performance of size 22 aircraft cables with conductors of type D.50.S silicon-magnesium-aluminum alloy, together with their associated terminations, and compares them with their copper equivalents. D.50.S cables and terminations can be produced down to the smaller sizes used on aircraft, with both stranded and solid conductors, with strands down to a diameter of 0.006 inch. D.50.S cable with D.50.S terminations give a satisfactory performance at a conductor temperature of 260C providing the conductors are of a suitable hardness and have not been softened by the cable insulating process, but D.50.S cables with copper terminations or copper cables with D.50.S terminations are not satisfactory at this temperature. D.50.S cables with D.50.S terminations withstand all aircraft environmental conditions including salt-spray. The combination of D.50.S and copper is unsuitable for use in salt-spray conditions. The main advantage of D.50.S conductors over copper conductors is saving in weight which occurs whatever basis of comparison is used. The greatest saving in weight occurs when the newer and thinner types of cable insulation are used and if solid conductors can be used in place of stranded. An estimate is made of the weight saving over the whole range of aircraft cable sizes, and of the weight saving if D.50.S cables were used on a V.C.10 aircraft. (Author)