RE: Gear box for an AXI
Check over in "glow to electric conversions" for a thread I started on converting the Great Planes 1/3 Scale Pitts S2B with an AXi 4130/20. For the life of me I can't remember what the name of the company is that makes the big belt drive I was going to use in that case.
The problem I was having is in getting enough thrust and pitch speed to make a 15lb Pitts aerobatic without exceeding the capacity of the motor. Best I could do on pitch speed was about 50MPH and 128oz of thrust, IIRC. Those AXi motors are slow turners, and you're very limited in how much you can gear them down without turning them into a rotisserie instead of a power plant. 2:1 seems to be the extreme limit.
I'm going to try a geared AXi 4130/20, 30 cells, on my big Ultra Stick sometime. 1200 Watts seems to be the max for this motor, though, 40 Amps on 30 cells.
Maybe AXi will come out with an even bigger outrunner that we can use on giant planes. MaxCim's got motors that can fly giant scale planes on direct drive. I don't see why AXi can't do the same.