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Old 05-24-2012, 07:35 PM
41Sqn_Banks 41Sqn_Banks is offline
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Quote:
Originally Posted by Crumpp View Post
Exactly. It was used to test the engine at altitude during service maintenance.
As said: There is no "override" for Merlin II/III engines. There is no device for extra rich mixture for take-off. There is only a cut-out to disable the boost control. But this was not used for take-off, as maximum take-off boost is the regular rated boost of +6.25.

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THAT IS WHY YOU HAVE PILOT ANECDOTES OF FLYING AT +16 LBS ON 87 OCTANE!
Great, show us the anecdote.

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If they tested the engine to 10.5lbs then a low engineering safety factor of 1.6 yields 16.8lbs.
Once again you forgot atmospheric pressure in your calculation.
10.5lbs (+ 15.0) is 100%
16.0lbs (+ 15.0) is 121,56%
This is only a factor of 1.2; a factor of 1.6 would be +25.8lbs (+ 15.0).

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Quote:
AIR MINISTRY
Air Publication 129
Revised November 1937
Royal Air Force
FLYING TRAINING MANUAL
Part I - LANDPLANES
Chap. II
Aero-engine speeds and boost pressures
66. (vi).(c). Aircraft should not be flow at the maximum conditions for level flight except in emergency, or when special operational conditions necessitate it.
Exactly. Only in emergency or special operational conditions the aircraft is flow at the "maximum rpm/boost for level flight" (later called "all out") limits and not above.
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