I just received two new Cyclon 15s last week. The early tests showing them turning 2000 rpm more than the best Nelsons.
The weight is only 4.5 ounces with glowplug and spinner and the engine is beautiful.
These are direct drive engines that would be EXTRA hot for AMA A gas.
I have my new hot Nelson for sale for $250, because I want to use the Cyclon.
The Cyclon 2.5cc, .15, engine has the same mounting pattern as the Nelson, so you should be able to drop it in.
The price is about the same as the Nelson and I should have it on my website this week.
If you want an earlier look, just email me at: dedmonson@comcast.net
and I will send you pictures, and specs.