My older one has an estimated 15 gallons of Powermaster 10-22 through it. That's 22% oil, half castor. The venturi is .272" bore and the spraybar is a Randy Aero unit (.156" dia.). Otherwise box stock, with a Thunderbolt Long R/C glowplug. The best prop I've found for it is the 11 x 4.5 Thunder Tiger Cyclone, launching at around 9,700 rpm.

Because the model is tailheavy, I'm running an OS .46LA muffler, but I have a new one in an Olympic with a Randy Aero CNC Tube muffler. Both run muffler pressure, and both run very nicely, although the new one has maybe 6 runs at most. They take some time to loosen up and reduce fuel consumption to a steady state. The old one uses a nominal 4 oz. Hayes clunk tank...can't say if that tank holds 3.5 oz or 4.5 oz, but it holds just a little too much fuel to get in under 8 minutes. Works pretty well.

That old engine has great compression, and there have been some long streaks of one-flip starts, including one without benefit of the battery! My drill is three flips with the muffler outlet blocked, three chokes with thumb solidly over the venturi, then about a half dozen fast flips to spread the fuel through the engine. This is on a F.Twister, so side mounted.  It will sound pretty wet...listen for that. Hook up the glowplug and pull it through. Should bump. Signal the judges. If it doesn't bump, choke it a couple more times (battery off) with the thumb not quite sealing off the venturi. Feel for bump. Signal...hit the prop, fly.

FWIW, I start out with 10-29 (all castor) (if I have it) for any new engine, but when the flying phase starts, I start getting pressured into using the 10-22. Haven't tried 5% nitro, because we're lucky to get the local hobby shop to stock 10-22. Since Powermaster's demise and rebirth, they don't carry it, but I'm hoping to change that by just walking in and ordering a couple of cases.     Steve

Thanks Steve sounds like a good motor. What sort of a run does it do when set up like this? Constant 4 stroke, wet 2 or 4-2-4?
Mike