were the engines upgraded before the crash to more powerful ones? or am i getting mixed up with th DH11O that infamously broke up??.
VX770 was employed as an engine test-bed by Rolls Royce at the time of the accident, it originally flew with four RR RA.3 Avons of 6,500Ib, these were considered a stop-gap to get the 698s flying. These were then changed to AS Sa.6 Sapphires of 7,500Ib, before gaining the 16,500Ib RR Co.10 Conways in August 1957.
Baloffski, Thunderbird, and Vega seem bang on as to the cause, being structural break-up of the wing following leading edge failure.
Many sources state that VX770 had been put through manoeuvres which were too much for the aircraft and which contributed to the failure, but it should be remembered that the prototypes were not as strong as the production aircraft. When the 698s were under construction in the early 1950s correct stressing for high speed jet aircraft was little understood by the industry,manufacturers, and to a degree by the research bodies, calculations often proving to be under done, unfortunately this was often found out through investigation after an accident.
Pistonrob draws an interesting parallel with the 1952 DH.110 crash, and the similarities were remarkable.
John Derry had been flying spirited (but entirely well thought out and safe) manouvres in the first prototype when the stb’d leading edge buckled and opened up causing catastrophic failure of the wing structures. Its wings were subsequently found to have only possessed 64% of their calculated designed strength, de Havilland accepting responsibility.
Very dangerous times, with very brave test and service crews whos jobs seem tragically overlooked when compared to wartime careers.
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