Av8tor,

I had a chance today to do some more testing on the Stihl while the wife was out shopping. She fusses about the noise when I run engines at home ratha than at the field.

Ran the Stihl first in the normal counter clockwise direction of Glow/gas made with 93 octane. Really couldn't tell any difference in the vibration. I remounted the EI just to go back and verify my original observations. Ran it in both directions. The mid range vibration is higher than it is below 3000 rpm or above 5000 rpm, but acceptable for use on a plane.

I raised the cylinder deck to a total of 45 thou and ran on Glow/gas mix. Some improvement in the 3000-5000 rpm range, but still too high to put on a plane. I didn't try shaving the piston skirt to get the intake timing back because there wasn't enough improvement with the deck raised to justify modifying the piston skirt. I think that the Stihl runs well on EI I will use it on another plane with EI ratha than Glow/gas.

I still need to find an engine that is suitable for the camera plane. The power requirements are not that high since the plane is designed for a flight envelope of 25 to 35 mph. I have a Homelite 25 cc and a McCulloch 28 cc which I have not yet converted. Any comments on which one might be the best candidate?

Will