On 11 May 2007 07:14:19 -0700, Kingfish wrote:

Watching the Convairs' engines
start, it became obvious why there's no mosquito problem on the ramp -
you've *never* seen so much smoke from a plane that wasn't on fire...
(note to Dudley H: Did those things puke oil when they were new??) I

Round engines are dry sump with a separate oil tank. After shutdown,
the oil left in the engine ends up in the bottom cylinder(s) whereby
it will eventually seep through the gaps in the rings.

Most of them require rotating a few blades prior to turning on the
mags to make sure there is no hydraulic lock ( could bend a rod) and
to spit any oil out the exhaust. It's the same reason you see the guys
pulling them through by hand in old movies.

When they light off, they throw oil mist and smoke out the pipes. You
don't want your plane close behind one of them or you'll need a wash
job.

New or old they all do it.