On Jun 1, 8:35*pm, Tina wrote:
The Mooney 201 has a ram air port, a half a foot under the prop
spinner. The POH tells us it can be opened at altitude for a very
modest increase in MP and we find maybe a half inch increase in
pressure. The idea of the thing is, if the port is looking right at
the air being thrust toward it by the prop (it can't be more than 6
inches or so behind it) *as well as the air impact from the airplane's
motion the air being 'rammed' into it should effectively lower the
altitude the engine thinks it's at. Well, a half inch of Hg is about
500 feet or so. The question is, though, wouldn't you think there
would be a way to capture a great deal more of the ram air effect and
really boost the engine performance? Who wouldn't like to fly at 24
square at 12000 feet without a turbo charger?

What makes me wonder about it is, even at 60 mph holding your hand out
of the window of a car subjects it to a significant backward pressure,
so the energy must be there.

An interesting question. I will have a stab at it but its just an
intuitive guess. Thrust is created by the prop pushing the air
backwards. If you are trying to capture that air into the engine,
there must be some resistance and therefore if you restrict the
ability of the air to be pushed away the thrust would be reduced. So
it must be a balance between not reducing the thrust and getting more
air into the engine to generate more power. I am also guessing that
for the ram air to be of much use it would probably be bypassing the
airfilter, which is potentially not good for the engine. although at
high altitude it is probably Ok, except perhaps for ice formation if
there was a lot of moisture in the air?

Isnt a Mooney fast enough for you Tina?
Terry