"Pat Flannery" wrote in message
...


Morgans wrote:

Of course, on some engines, that was grounds for grounding the aircraft
to inspect the engine, to see if it was damaged from exceeding 100%
power.

On the P-51 Mustang, this was called "War Emergency Power"; it would give
some extra zip, but would also destroy the engine in around ten minutes
after engaging it. :-)

Pat

Actually it's 5 minutes. WEP on my V1650-7 Merlin in the 51 could be
achieved by breaking the throttle gate . I never used it...actually never
needed it really. Under 5000 feet, normal max power at 61 inches gives you
all the power you need to exceed the operating limitations for the engine,
and at altitude on cross country, I was more concerned with saving a buck by
not stressing the engine anyway :-)
Also, if breaking the gate and using that extra 6" of MP, the Mustang should
be using 130 octane fuel and not the 100LL we poor folks have in the tanks
most of the time :-) 100LL limits the 51 to 55 inches anyway, so you can
forget using War Emergency Power for the general Mustang owner (Hoover might
be an exception since he has an expense account most of us envied :-)
I didn't fly the 51 in combat, which I guess is the gist of the discussion,
but in combat, if you used WEP, it was a 5 minute emergency only deal that
meant a complete engine breakdown and inspection within 5 hours. Needles to
say, the 51 drivers in combat didn't misuse their engines by using WEP
indiscriminately. Actually, if you had to go to WEP in combat, you were
almost always defensive against a hard turning opponent, and if you got to
that point, you were in deep do-do already!
Most of the guys flying the 51 in air to air tried to keep the temps down
(Coolant to 121 degrees was a doubtful trip home) For ACM in the 51, 61
inches and 3000RPM will give you a wide airspeed and energy envelope to
maneuver in all 3 dimensions. Going through the throttle gate was a sure
indication you had done something REAL wrong!!
Anyway, hope this helps a bit.
Dudley Henriques