Quote:
Originally Posted by NZtyphoon
I'm sure it happens - what is needed is some empirical data to show how long it takes for the oil pressure to drop below the minimum safe level. How much negative g is needed to lower the oil pressure enough to cause damage? The Pilot's Notes General, for example, describes one condition imposing too much negative g is a succession of slow rolls - so how many pilots are going to indulge in successive slow rolls during combat? What other combat conditions will impose enough negative g for long enough to damage the engine?
The normal oil pressure for the Merlin is 60lbs/sq.in, with a working minimum of 30lbs/sq.in. For gameplay a rough rule of thumb could be anything below 30lbs and the engine begins to suffer progressive wear (according to the Pilot's Notes General it doesn't take long for damage to occur once the oil pressure drops below the minimum).
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The typical rule of thumb for any combustion engine is you need at least 10lbs of oil pressure for every 1000 RPMs. That is bare minimum. The volume/flow of oil needed is different for every engine. One of the reasons to have a good volume of oil / high volume oil pump is the hopes that during normal startup, by the time combustion happens you have already lubricated the bottom end before engine start (during the cranking process). If the pump only put out 10lbs per 1000 RPMs, the engine could be oil starved every time you fire it up. The real key is having high volume when you need it and be able to slave off excess oil pressure via a bypass valve when you don't. Too much oil pressure can also wash the bearings and cause failure as well.