On Feb 10, 12:57 am, cavalamb himself wrote:
wrote:
On Feb 9, 2:10 pm, Anthony W wrote:

I was wondering about that too. The compression ratio doesn't seem high
enough to require that. Perhaps a thicker head gasket could be used to
lower the CR so it would run on auto-premium to make it cheaper to operate.
...

I once owned a McCulloch two-stroke four-cylinder drone
engine that had been modified this way to derate it from 72 hp to 50
and to allow it to run smoother at a lower RPM. Terrible engine,
commonly used years ago in Bensen's gyrocopters. They'd been built by
McCulloch for the military, who used them in target drones for anti-
aircraft gunners to practice shooting down, so the engine was designed
for a 15-minute service life or something like that. In homebuilts,
they vibrated like mad, and the mag would get hot and quit. The
carburetor throttle shaft would wear the thin carb barrel walls out in
no time flat and leak air. But cheap they were, light, and plentiful.
Couple pictures of one, and one of a Franklin drone engine, too:
http://www.barnstormers.com/EVENTS/0...museum-21.html

Dan

Perhaps, like teh VW, a spacer at teh bottom of the cylinder can be
used to adjust compression?

I know someone who added a third piston ring to his pistons.

He said he got 95 hp, didn't say for how long, and I don't think he
ever ran it full bore for very long.

--

FF