I picked up a weedwacker featherlite 21cc and a CH ignition system. It runs a 15x6 at 8000 rpm. That is now pretty unimpressive to me. I would like to make a 7-foot span eindecker. It is looking like my little engine will not cut it. I have a Ryobi 31 cc to convert.

I will stick with the CH ignition in any case.

Should I:

1. Hop up the 21cc and see what I can wring out of it? Try a bigger carb and port it and remove as much superfluious aluminum as possible with my milling machine and lathe.
2. Do the Ryobi, port it, bigger carb lighten it as much as is reasonable.
3. Select some other engine? The CH guy like Homelites.

Eidecker's ain't fast. The Ryobi turning an 18x8 at 7400 rpm is going to make a LOT more thrust. B ut its long
The Homie is shorter and wider, just the thing for a radial cowl. The 25 will out turn the featherlight but not the Ryobi. The 30 Homie will out turn both. Weighs less than the Ryobi too.
The CH guy

Yep, good advice.

AV8TOR

I had a 30cc homelite on my sons Balsa USA WWI DVIII.Thats the high wing monoplane.
84 wingspan.14.25 lbs RTF dry[no gas].
18x8 dynathrust,and an 18x8 top flite.Both of these are not the most effecient prop in the world as people say but it got the job done and without a lot of prop noise.
Anyway,flew around most of the time at 1/2 to 3/4 throttle with no problem.No mods where done to the engine except a pitts muffler.Kept the flywheel and mag on for weight.
I coul hand start it everytime with only 3-4 flips.after i choked it.

I aquired a 41cc zenoah all the useless parts are milled away.. Prop hub is done. Mount plate done. Muffler.........working on that. CH ignition, yep. CH says they have done this engine. It is off a "green machine" leaf blower. I have a 20-8 prop on the way. CH is a great resourse, can't thank them enough.

A Featherlite 21 turning a 15-6 at 8000 is doing pretty good for that engine. I doubt you would ever get much more from it.