Originally Posted by robj
Some more testing with mine this morning. I haven't really noticed the right roll under power because I do more slow stuff or only WOT verticals.
Put on a 12x6 this morning, liked the way it flew, no heavy TR issues, plenty of power, actually hovered nicely. Then did the straight and level WOT. Woaa!! plenty of hard right roll. Yikes!
Put on a 10x5 and tried. Useless, no power, not even to sport fly it.
Went back to the 11x5.5 and tried the WOT straight and level. No roll in mine, I did it twice. Plenty of power.
Some pics of my trims..
OK, so this is interesting. Here's a theory to test:
The roll tendency is not from the motor's torque (that would want to roll the plane left-opposite direction of the prop), but from the prop wash. If you've ever looked at the prop wash coming from a boat, you'll see it's a vortex that rolls in the same direction as the prop rotation. Same principle with the plane - the prop wash coming from a counter clockwise rotating prop will create a counter clockwise rotating prop wash, which will want to roll the plane right as it hits the surfaces of the plane. I don't think RobJ or Chopper see the roll tendency with the 11x5.5 because they don't have as big a flat surface for the prop wash to push against as folks with wheel pants do. I think RobJ experienced his problem with the 12x6 because he's got a larger column of prop wash that's hitting more of the wheels, wing, and tail. So, to fix it, you would either need to reduce the surfaces getting hit by the prop wash (like the wheel pants) or reduce the size of your prop so the wash isn't as large.
My guess at the solution if anyone with the problem cares to test it.