Ken Welter wrote:

  I am now running a 2.95 ratio and the intake is a 51mm Weber with a
racing beat manifold, and as I mentioned the ram makes 1000 rpm at
15000 ft and if I pull the ram back I cannot hold level flight the
ram also leans the mixture as it creates a pressure differential
between the Venturi and the float bole, you you hit it on the nose
intake is the at high alt and the aircraft engines are very crude
with there untuned pipes,square bends,bad head design, and crude carb
so when the piston heads down and wants air it just cant get it that
is why they are left left behind at high alt and the rotary is not at
as much of a loss.

The rotary engine does indeed breathe well at high RPM's.
IMHO I think you would be better off with an aircraft carb or one of Tracy's 
EFI systems where the mixture can be changed manually at any time and will 
change automatically with altitude if you do nothing. That way you can
get the benefit of the ram air at all altitudes to increases HP
and intake manifold pressure.

Not all aircraft piston engines have crude intake manifolds. Most are very
efficient indeed. In fact many have better BSFC's than car engines and
that would indicate an efficient intake manifold with good breathing. 
Some are even tuned. The main problem with A/C engines is structural. 
They have a high power to weight ratio and therefore they are high 
strung piston engines structurally speaking.

Here is a picture of Ken's ram air device.

Paul Lamar
 
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