[hrench]

my team 1108 was one of the few that built a catapult for rebound rumble in 2008 and we started and ended with coiled steel springs running it. We made surgical-tubing springs and tried them for a while but they stretch over time, they oxidize and where they're fastened, they tear. Steel springs had no degradation. I think we were able to get more energy into a smaller space too.

At first when we installed the coils, we thought they would require a cable down the middle like on your garage door, but no one ever mentioned it.

Note that one of the 'bots' on the game-introduction video visibly has a compression spring catapult.

I think we'll end up with metal springs again, but I can't say that for sure now. Also, air springs a possibility.