Hi David,

The trouble is that I'm giving away away so much efficiency running an 11" prop but you get nice smooth turbine like power. The old .75 I'm used to is rated to put out about 2.4hp. 1300W just isn't going to cut the mustard at 100mph, BUT at 60-70MPH with a 12-13" diameter prop 1300W is in the ballpark. The math says 8+lbs of thrust at 100mph = 2+horsepower.

I morally object to people flying a classic with a 14" prop turning in the sub 10's , it'd be like pulling the V-twin 2-stroke out of my TZ and replacing it with a 650cc single 4-stroke.

The Scorpion on 10S (it's rated for 12S), pulling about 65A static with the 11x9 gave very similiar performance to the .75 two stroke and honestly up to about 9000rpm was very smooth but when pushed beyond that the whole thing got very bendy. I was running glow props on it as well, not the floppy E props. When you compare how solid the front end of a glow motor is to an electric you can see it's asking a lot from it. But it's all experimentation. The 8mm shaft wasn't flexing from what we could see but the "spigot" (for want of a better word) that the bearinges and stator are mounted into. On the rear mount arrangment my friend was using, you could grab the prop and bend it from side to side watching the can flex around in relation to the stator.

Don't let mine and my friends not-so-positive experience with the Scorpion outrunners put you off from experimenting. His was a S-4035-330 he intended to run "rear mounted" on 12S in a Falcon 120 but it was too bendy for that. He turned it around to a front mount, with a 10mm ply box around it with external rear bearing support and it's bench testing a lot better. Both motors up to about 9k were fine but started getting out of shape after that. I'm beginning to think a "typical" outrunner design doesn't scale well, just like we don't see too many .15+ sized engines based around the design of a Cox .049...