Pitts S1D, 160hp, IO320. Been locked up in the heated/dehumidified hanger for 18years, I can't afford to fly it anymore and I’m ready to put it on the auction block and move on to restoring an old truck, more my speed now days. The RPM of the AC engines is really limited by the prop’s tip speed. To much more than that and the tips go supersonic and loose efficiency. The buckets in a 360ci 4 cylinder are pretty big so that is another factor in the low revs. They make lots of torque though and I say again, a lot like a tractor. Being air-cooled they are real gas hogs also, they have stayed away from water cooling to keep things simple, cooling is just one more system to give ya a problem.
Denny Graham
Sandwich, IL
