Well, this year we built an all wheel drive- all wheel steer (4 castors or 2 wheel skid steer at the push of a joystick button), rolling forklift, catapult that will launch a 6 pound, 40" diameter ball well over the 6'6" high goal post!
The launch mechanism is pneumatic, powered by an on board compressor and series of regulators and solenoid driven, bi-directional valves that delivers 60lbs of pressure to 4 cylinders in a bifurcated system that allows for maximum flexibility. The power plant is comprised of twin CIM DC motors that deliver more than enough torque (I forgot the actual number on the data sheet in work), at 5500 RPM (no load).
Twin OPTICAL (that's for you motorbill) pick-ups monitor the motor speeds and provide data to the on-board microprocessor which makes necessary decisions/adjustments so that the beast will go straight (or wherever you want it to go) when in skid steering mode. This system also incorporates an absolute encoder on the castor turning motor. The encoder feeds the microprocessor gray code, with this, the microprocessor always knows which way the castors are pointed, and can make adjustments as needed if uneven wheel friction or being bumped by another robot knocks us off course.
By the way....did I mention that these are HIGH SCHOOL KIDS?
I'm sad to say that to the best of my knowledge, there are no British Leland parts on board, however it is quite possible that some of my Sprite is riding along. The tools we use to do the metal fabrication/construction are from my shop at home so some 40 year old metal shavings may be unwittingly incorporated in the design!
On their death bed, nobody ever said, "Gee I wish I'd spent more time at work!"