Catapult consistency

So my catapult decided to kill itself suddenly and it has become very inconsistent. I have checked everything on my structure and nothing seem to be wrong. Nothing is loose, bent, or broken. What are some things on a catapult that will effect consistency that I should look for. The balls are held by a 1x5 channel with standoffs btw.

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Remove it and build a flywheel or slipgear. Just kidding, way too close to worlds to do that. Is it not being consistent or is it just consistently off?

Inconsistent. I would much rather be in a position where it is consistently off…

Then these are the specific things you would want to check for.

  1. First I would check to make sure there’s nothing loose on the stopper of the catapult. If that stopper is loose it’s going to cause your catapult to shoot differently almost every single time.

  2. Make sure you don’t have any bent, mangled, or twisted shafts. Of course, this one only applies if you aren’t using high strength.

  3. Make sure that the path of your rubber bands is clear. If the rubber bands are getting caught on something as they’re contracting, it would also cause your catapult to shoot in seemingly random places.

  4. Check your slip gear and see if any of the teeth that are supposed to be there are wearing down. With prolonged use of a catapult parts are going to start breaking. It is possible that over time the teeth on your slip gear are wearing down enough where it will sometimes slip before it is supposed to.

Hope this helps!

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I would check the slipgear, replace the motor, replace rubber bands, check for obvious bending in structure, etc. The obvious stuff you’ve probably already thought of.

I would record a solo-mo video of it shooting several times and see what differs betweeen each shot.


Of course, you can say that the catapult is inconsistent and there’s nothing wrong with it. But nothing will beat multiple eyes on the robot. If possible, could you provide any pictures of your catapult and catapult mechanism?

Could you post some pictures of the catapult or some videos of it shooting inconsistently? The forums should be able to help you find a solution but it’s hard to do that with no idea what the issue might be.

Good luck!

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If your standoffs holding the ball in the catapult are bent it could go wrong, or if your stopping mechanism. What happened to me one time is my catapult broke a extra tooth of one of my slip gears, be sure to count those

Make sure the ball is seated nicely in the carriage until the catapult hits the stop. If the ball jostles around during launch it messes things up. Slow down a video of it firing to see it closely

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We had our catapult completely stop working as well. Unfortunately this was at the U.S. Open right before qualification matches. What we found, was our gear train bearing wear slightly twisting due to the mass amount of torque in our catapult. If you take of the tension, make sure all of the bearings are straight, then put the tension back on. That is what worked for us. We also had to reorient our bearing from vertical to horizontal. This helped cope with the catapult’s torque.