Torsion Spring Catapult

We’re considering using a torsion spring as a way to store energy for launching the ball with a catapult. I was wondering if other teams have tried this, what their results were, and the specs of the spring they used.

I did a lot of looking into torsion springs and felt that the largest springs supplied by McMaster wouldn’t produce enough torque in a narrow enough package to be effective.

One of our other mentors welded the ends of a compression spring inside two steel tubes to get a make-shift torsion spring. It had a lot of force, and was able to throw the ball fairly well and could have been torqued more (we over-torqued it and broke the welds though). However, one thing I saw as a potential issue is that these springs did not seem to ‘snap’ forward quickly; whether this was due to the type of spring, or simply because we were underpowered, I do not know.

Torsion power seems very attractive this year though, as you can pack a lot of power into a small package; but getting the necessary torque without any mechanical advantage will be challenging.

Look into garage door springs, they’re heavy, but they should be able to pack enough punch.

Have used torsion springs in the past. A modified automotive timing belt tensioner works great for this!


if any of you has a out line can you send it to me.