I'd estimate 115-130. As soon as my needle gets underneath 150, I start to initiate the crash landing sequence.
gotcha.
i did a few test for 10 minutes just out of curiosity. Quite interesting results. All tests conducted in the TA with current update.
152 crash tests - film link 2mb .ahf
Crash 1 - 00:15 - Speed: 80mph - Surface: Grass - Impact: very soft - Result: left wing broken and fire started
Crash 2 - 01:15 - Speed: 125mph - Surface: Tarmac - Impact: very soft - Result: no structural, no fire
Crash 3 - 02:23 - Speed: 90mph - Surface: Tarmac - Impact: very soft - Result: no structural, no fire
Crash 4 - 04:05 - Speed: 250mph - Surface: Tarmac - Impact: soft - Result: instant death, no fire
Crash 5 - 05:17 - Speed: 195mph - Surface: Tarmac - Impact: soft - Result: instant death, no fire
Crash 6 - 06:00 - Speed: 125mph - Surface: Tarmac - Impact: soft - result: no structural, no fire
Crash 7 - 06:45 - Speed: 100mph - Surface: Tarmac to grass - Impact: hard wing first cartwheel to slide - Result: both wings broken, fire started. Sat burning for 1.5 mins, did not die.
Crash 8 - 08:55 - Speed: 100mph - Surface: Tarmac - Impact: hard inverted - Result: heavy structural failiure, no fire
Crash 9 - 09:55 - Speed 135mph - Surface: Tarmac - Impact: very hard inverted - Result: instant death, no fire
So, without intending to test this part, it seems the only time a fire was produced was when coming into contact with grass. Though of course this was quite possibly coincidence. The highest survivable speed was 125mph although did not test between 125-150 etc.. 100mph inverted landing was no problem for the pilot to survive. Yet 80mph very soft landing on grass caused a fire and broken wing. NOTE: no fire was visible from the cockpit internal view at any time. Clearly the grass thing might not be an issue because i assume you were landing on tarmac when it happened.
strange results, not sure if they help at all,. Was fun to crash 9 times though
S!