Just came across this 2003 interview with Franz Steigler:
http://109lair.hobbyvista.com/articl...er/stigler.htm
He talks about MW50 and it's use on the me109.
Did you ever have the GM-1 boost or MW-50 in any of your planes?
Oh yeah, we used it quite often�in combat you know.
How long did it last?
Uhh,you were not allowed to have it at more than 5 min., you know,if you used it 10 minutes, then motor has to come out.
It makes the engine worse?
It wrecks the motor.
And this was for the higher altitude?
Higher,yes.
And at what speed could you get up to?
Oh boy,I don't remember,450 or 500 km.
Like you said, you could only use it for 5 min. otherwise you would burn out the engine. How many 5 min. intervals could you use? Did you have to shut it down for a period of time to let the engine cool?
That's okay.that uh.it didn't matter. You, but you never used it for five minutes, a minute, minute and a half and that's it.