Friction and thrust

[writchie]

Electric Ducted Fan Airplanes generally perform at about 2 - 3 g/w where the watts are input watts (not motor watts). This is your starting ballpark and it translates to about 29 ounces of thrust from 330 watts of input power.

The only reasonable candidate motor for this is the fisher price. You could get perhaps 1 - 2 lbs from each.

IIRC we have to protect the FP motors for 30 amps. Allowing for some loss in the speed controllers we should get a shaft output of 150 watts if can present a torque load of about 21 oz-in with a motor speed of about 10,000 RPM. The motor could probably be pushed to 40 -50 amps for short times. You will need to find a propeller or ducted fan unit that can fit the motor and provide the suitable load. Ducted fan units in the right size range are generally sized for 1 - 2 kw brushless motors.

There are obvious safety hazards. The ducted fans are a bit safer.

I am a little surprised that FIRST hasn't closed down this option by rule. Its one thing to have 10,000 RPM in a closed gearbox and quite another to have it on a 3 - 8 inch rotating cutting blade. A rule say limited rotating parts to 3-5000 rpm-inches of diameter would take this off the table.