I went over to the local small engine guys shop and picked up a Poulan 25cc weedeater engine(20$) and followed these instructions.

Bought the muffler and prop adapter from Wacker Engines and a Zenoah velocity stack and glow plug adapter and 16x8 Master Airscrew prop(atomic hobbies).

I cut off the excess parts off the engine and used a holesaw to cut out the flywheel center. I trued up the remaining hub to a couple thousandths with a dial indicator. I made an aluminum mounting plate with cable crimp standoffs and 6/32 machine screws.

I used 1/3 15/20glow and 2/3 87oct gas and I am getting about 7400rpm with a reliable idle at around 2000rpm on a 16-8 prop. I might be able to idle it down a little more maybe 1800 or so but it gets pretty rough without glow power that slow. This engine had been used very little before somebody backed over the wand with a car so it might need to break in a bit yet.. I tried a few different glow plugs and ended up with a tower hobbies r/c plug that worked the best. I haven't tried many plugs mainly old idle bar plugs(they didn't work well). Sometime I will have to get a 4stroke plug to try.

Ran it a little more and idled it down to 1800rpm. It will transition to 7000rpm pretty quick and then it will slowly climb up to about 7400rpm. I will need to screw around with it some more.

It weighs 44oz. with the prop on it ready to fly. I am thinking of putting it on my Dragon Lady but it might be a little much for it. The Magnum .91rfs I have for it weighs considerably less and turns a 14-6 at 10000+. Maybe a little bigger plane is in my future(maybe a BIG oldtimer??).

What do you guys think??