[MikeJ675]

With the requirements, there's a lot of possibilities...

40" length is a lot to work with.

Some of the motors commonly used in robot combat could be 'interesting' if used properly.

S28-150 Magmotor

This is a smaller, lighter version of the popular S28-400. Same diameter and powerful magnets, just in a shorter, lighter package! And would you believe a whopping 3 horsepower from a 3.8lb motor?

3" Diameter, 4" long
1/2" diameter shaft with 1/8" keyway, 1.75" long
24V (can be run higher)
3 horsepower
1970 oz-in Torque
Max current 285 Amps
82% Efficiency
6000 rpm
3.8 lbs
Neodymium magnets

There have got to be fun ways to use one or two of these...

For the truly insane-
ETEK motor by Briggs & Stratton

This is one of the most powerful DC motors available. There is nothing like it out there. Many of the most powerful spinner robots out there have been using this motor with great success (including Nightmare, Son of Whyachi, Moebius and many more). WARNING: this motor is NOT an ordinary motor, and should be handled with GREAT care. It is very capable of serious power and should always be completely secured before applying any power to it.

24V to 48V (has been run up to 72V)
72rpm per volt (3456rpm @ 48V)
20.8 pounds
7.91" diameter
5.64" length
7/8" shaft with 3/16" keyway and 3/8-16 Tapped center
Torque constant: 1.14 in-lb/Amp (0.13 Nm/Amp)
Max motor current: 330A for 2 minutes

could you imagine the power of this thing at 72v?(estimated 15hp at 48v)


Assuming a new supply is found, the AME D-pack motor is amazing in power to weight and cost to weight(the only downfall being the HUGE stall current)

12v stats(they will run at 24v)
Angular-velocity constant: 592 rpm/V
Peak power: 4.78 hp
Stall current: 1240 A
Stall torque: 2770 ozf·in

with any of these, though, the problem is getting the power to the ground. High traction tires and some creative gearing solutions could easily provide the means of getting to the speed you want.