The crank in not in contact all the time but the oil is sloshing around as
the airplane moves. When the level gets down to where it isn't contacting
the crank, the oil stops being blown out the breather (at least in
meaningful quantities.)

Mike
MU-2

"Matt Whiting" wrote in message
...
Mike Rapoport wrote:

But you are putting more heat in because of having the crank contact the
oil
more of the time. The temp will be higher.

Is this true in Lycs and Contis? I don't know about the airplane
engines, but car engines have the upper fill limit established to
prevent this. Having the crank contact the oil will froth it pretty
quickly and the oil pump can't pump aerated oil very well. This is why
the dipstick always has a warning not to overfill. I'd be surprised if
airplane engines permitted a fill to the point of crank contact. This
is generally only done intentionally on splash lubricated engines such
as those found in cheap lawnmowers.


Matt