A friend of mine is working on a Corvair modification for a Zenith plane. He
has had the machining done to accept VW cylinders, has the 5th bearing etc..
He gave me the inside dia. of the VW cylinders as 3 11/16 in. The stroke is
based on the standard Corvair Crank. He understands that to burn premium
unleaded auto fuel and get good hp, a compression ratio of 9.5 : 1 works well
at sea level. Most of his flying here will be in the 6000' msl range and up.
Because the air is thinner up here, he believes that a smaller combustion
chamber size would work and that with a pre ignition detector installed, he can
determine when he would need to burn higher octane fuel if going to a lower
elevation. The question is how much smaller would be the combustion chamber be
to equal 9.5 to 1 at sea level. He is thinking around 51 cc, but we don't know
for sure how to verify this. We realize it is complicated by a number of
factors. Any suggestions about this or ideas of where to look or who to ask
for the answers would be appreciated.
I have the engine mounted on my KR2s, one wing left to paint with the final
coat, and the instrument panel ready to paint. I had no idea how many wires
would be required and this is a fairly simple system. However, it looks like
this may really happen.
Dan
