Effect of boost control cutout prior to +12 psi boost modifications

[Seadog]

Originally Posted by ICDP

I must admit to being kind of lost on what your stance/opinion is. Now you are saying you want to be able to fly at +12 lbs boost becuase there was a war to win and that was more important than a broken engine. So you accept that flying around in combat at +12 lbs boost could wreck your engine, but that the pilots didn't care?

Dowding's memo reports a number of combat situations that led to increased engine wear and thus to bearing failure and basically these centre on high G/low oil pressure manoeuvres and inverted flight, both of which led to oil starvation due to low oil pressure and obviously have nothing to do with 12lb/3000rpm flight. Prolonged steep climbs at high boost/rpm was a potential problem area (but why would Dowding mention this if pilots weren't doing it historically?). I previously posted a test report showing that 8.5 hours (in repeated 5min intervals) at 12lb boost/3000rpm did not cause increased engine wear:
http://www.wwiiaircraftperformance.o...bs-14nov39.jpg
Basically, it is a question of modelling the cooling and lubrication capability of the aircraft and in straight and level flight 12lb/3000rpm will not cause problems but pilots need to keep a watch on their oil pressure, temp and engine coolant gauges during prolonged steep climbs, and their engine RPM during dives.

So if I am chasing/being chased by a 109 and I'm in level flight and I pull the boost override, I have a very high probability of being able to run at 12lb/3000rpm until I run out of fuel. If I make repeated steep climbs and let my temps and pressures stay in the red, then my probability of engine failure increases. It is a question of accurate flight modelling.