Quote:
Spitfire XI -- EN409 -- Multiple wing rivet failure in dive.
Spitfire XI -- EN409 -- Prop/gear broke off in dive.
It is indeed the aircraft tested by Fuehrer Martindale. I would like to see what happens with Thunderbolt in a speed exceeding M=0,9!
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Not just was EN 409 the aircraft Martindale had his accident in, it had been used for high speed testing since late 1943, before finally being lost at the end of April 1944.
The figures I have seen show it reaching mach 0.89 when being piloted by sq/ldr Tobin in late 43/early 44.
In contrast, US trials of a P-51:
"In July 1944 Wright Field test pilots explored the high speed dive characteristics of a Merlin powered Mustang. A series of dive tests were made starting from about 35,000 ft. in a test airplane equipped with a mach meter. The idea was to explore the effects of compressibility such as buffeting, vibration, control force changes, and so on. Initial dives showed the onset of the problem to occur at just under mach .75. Additional dives were made, usiung three test pilots, which carried the aircraft sucessively to mach .77, then .79, and up to mach .81, and finally to mach .83 (605 mph) As the dive mach number was increased the compressibility effects became more violent, but the aircraft wsa still controllable, and it was possible to fly it out of the problem when desired, at mach .83 the shaking and buffeting of the aircraft was so strong that it was decided to explore no further. The airplane had suffered considerable structural damage and was written off." (America's Hundred Thousand)
and:
Flight Research Branch, tests of P-51D:
"The airplane has been dived to a maximum mach number of 0.85, and on several occasions to 0.84. In each case the pilots reported the vibration became extremely heavy beyond 0.80. In each dive to 0.84 or above the vibration becames sosevere that the airplane was damaged. The leading edge skin of a wing flap was buckled between rivets, a coolant line cracked and hydraulic line broken due to vibration on various dives to 0.84 and above. "