Result of Tests.
Tests undertaken at the instance of the American Advisory Committee for Aeronautics showed that 80 per cent. of the wires tested failed by the free end pulling through the ferrule, the remaining 20 per cent. failing by fracture, the stays possessing an average efficiency of 68 per cent. of the maximum strength of the wire. Although various modifications, such as tying the free end to the ferrule with fine wire, as in [Fig. 105], resulted in an increase in total efficiency, average European practice consists of that shown by [Fig. 104]. At the present time the solid wire stay of the form dealt with is used mainly for the bracing of the fuselage frame, and the internal wiring of the tail planes.