RE: Nelson 40 info needed
haikt, I'm Chuck Matheny. I've flown AMA Fast since 1985, but never went further than Oregon to fly in anger. Every Summer all the pros from Texas would come out here to fly the Bladder Grabber. The only guy from around here to make the National tour is Jeff Rein.
I've run the F1 K&B 6.5 and it ran great with 30-40% nitro and a 7.2x8.6 APC. Trouble is they discontinued that prop, but something similar will work. These engines launch at 22,000 and unload impressively with an open header.
The FAI engine is designed for a 25-26,000 rpm launch with a 7x7.5. Such a tiny prop needs a low drag and light plane.