pic: Revised Ball Shooter

[dtengineering]

It IS possibile to build a one wheeled shooter that won't damage the balls and still achieve the 12m/s that is allowed (or close to it.)

We originally used the 9"x2" Skyway pneumatic wheel pictured at the beginning of this thread. It worked GREAT... but left, as mentioned, little pieces of foam and skin lying on the table where we had the mock-up mounted. We tried machining off the tread, but it still "visibly abraded the surface". So I posted the "Ball Damage - Follow Up" question mentioned above to the Q&A forum.

We have since revised our design, using two 8" Skyway kit wheels mounted a couple inches apart on the same shaft (it is still, essentially a single wheeled shooter), and adjusted for the decreased radius by bringing in the "wall" that compresses the ball by about an inch.

If you do the math... the 8" wheel is 20cm in diameter, or about 60cm in circumfurence. Spin it at 3000 rpm and you get 1,800 m/minute (30 m/s) linear velocity. Assume the ball will be travelling at 1/2 the linear velocity, and you will have all the speed that you are allowed... along with a comfortable margin to account for ball slippage, etc.

We've fired brand new poof balls from this set up dozens of times with NO visible damage. None.

FIRST does not mess around with its rules. If it is in the Q and A... it is in the rules. Shred balls at your own risk.

Jason