Single Motor Catapult

Hello Everyone,

Oen of my teams managed to make a single motor catapult. However, we still couldn’t figure out how to make the launcher. We tried many different combination but none of them seems to be working properly. I mean the shooting accuracy is still very low. Below is the latest version we designed but still not consistent enough. I was wondering if anyone can assist us with this? Any help would be highly appreciated.



I assume the catapult lowers and launches, since you mentioned it is working but the accuracy is low. Is it not going far enough or at the right trajectory?

Distance and trajectory are based on amount of force (your rubber bands) and shooting angle. Think of it like kicking a field goal or shooting a basketball. The closer the robot is to the bucket, then it needs to shoot closer to 90 degrees (higher arc)… and further away it needs to shoot at flatter angle (like a 50 yard field goal).

I assume the robot will drive up to the plastic sheet and launch the balls from that point. If so, then you will want to catapult to release the balls earlier (closer to the 90 degree part). You can place a long shaft across the robot so that the catapult can hit it early on, and it will cause the catapult to release the balls at a higher arc.


Thank you, our main problem the launcher design - the thing that holds two balls. It needs to be redesigned.

BTW, the part that holds the 2 balls is very similar to what our team uses. I noticed that yours is a 12x7 (6"x3.5"). Ours is 13x6. We found that a 12 beam across is too tight for the balls and a 13 or 14 would work better. Hope that helps. Good luck!


Thanks! That’s what we were trying to find out. We will try it tomorrow. Thank you!

It worked. Thank you.

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Great to hear, and good luck!