Hi Malcolm

IIRC the Matts were running the 15 wind and 22x12's in France, they flew slow for sure but seemed to cut through the wind as good as anyone else. I am not sure of the rpm they were getting on that setup though.

Air in Canada Well its definately thin here in Calgary, all my numbers are at 3500' asl. At sea level I notice a small increase in draw usually, maybe 2-3A. I will try the repitched 21x15W, although my feeling is after seeing the numbers that it will be too much load. With the 30-10 it would spin the same rpm as the 21x14 but with about 3-4A higher draw....regardless, I know the motor wont smoke at 3000+W so I will try it and see There is way beyond sufficient power with the 21x14 (my Twister is 4930 grams so its not light), so I suspect that I will very likely go back to the 21x13W to reduce the load....as it will probably have plenty of power as well. That was the prop that the motor was designed around anyways.

For spinners, if you want to get air into the motor and not use the folding prop setup, Great Planes as well as a bunch of other places make light aluminum backplate plastic spinners that you can easily cut a hole in the front of. Probably the cheapest, easiest way to get a lot of air in your motor.

http://www2.towerhobbies.com/cgi-bin...?&I=LXEBF0&P=7