On Tue, 31 Aug 2004 22:32:29 -0400, "Stan Kap"
wrote:

Hey Corky,

Forget about the engine, just add a large pipe to your mouth and jet that
out the back of the aircraft. There's so much hot air coming out, you
should break the sound barrier. The amount of thrust created by this affect
will be negligible at best. Get out your thermodynamics book and see for
yourself.

The augmenting effect of exhaust has been used for years in
aircooled engine installations like the Cessna 310. The exhaust
velocity is used to create a lower pressure in the cooling air
outflow. Even if he doesn't gain much thrust his cooling should
improve considerably, and less cooling drag translates into more net
thrust. If the P-51 guys thought it might work, it's worth fooling
with.
The only concern I might have would be the pulsation effect on the
radiator core. It might cause fatigue and failure after some time in
service. Even with the exhaust discharge downstream of the radiator,
the outflow may rumble enough to damage the rad.


Dan