Consistent shooter

[Pretzel]

Originally Posted by Duncan Macdonald

For teams using surgical tubing, what have you done to improve consistency? I built a surgical tubing catapult in 2008 and it was never exactly the same between matches. This didn't matter much when throwing a ball over a bar. Does the variation come into play when aiming for a goal?

Our team didn't end up using surgical tubing but I had thought up a way early in the season to ensure consistency between matches with surgical tubing.

If you wind up the surgical tubing on two drums, then unwind it just enough to attach it to the plunger or whatever it was propelling, you could then add a load sensor to the surgical tubing or the motor such that it measured the amount of tension in the tubing. Using two motors (Bag motors would would fine for this) you can have software that causes the drums the tubing is wound on to tighten or loosen the tubing depending on how far you want to shoot and how much the tubing has stretched. This keeps the tubing at the same tension for every match and also allows for lower powers settings in order to pass or shoot from a different distance.