Help with rubber bands for catapult

Hi our catapult is having issues and it has trouble pulling it back at the last bit. I know you can use triangles to evenly distribute force throughout the pull, but I don’t know how. Could someone please tell me how or link me to a guide. Thanks

I’m not sure a triangle is really the best thing to do in this situation. (Though it’s not that bad of an idea) Personally, I’ve found that more rubber bands over a shorter distance provides more force than less rubber bands stretched out really far.

Anyway, my intuition tells me that the second point in the triangle on the carriage should be relatively close to the stationary holder on the tower. But I don’t have any evidence to back that up as the best solution.

Alright I’ll try it out thanks

Could you post some pictures so we can get a batter look? Thanks!

The triangles aren’t to have a “more even pull across the catapult,” persay.
They’re actually because you want to have basically no force after some point at the bottom of your catapult so you can hold very easily. This happens because the force of the rubber bands is perfectly parallel to your catapult arm.

Thanks for the input and we will post some pictures as soon as we can

are you using v5 motors? if not how many motors are being used for your catapult?

2 legacy motors

Have you checked the internal gears? its possible they’re turbo or high speed, which could be causing the loss of torque

Yes they are torque geared

The catapult used to work just fine and we didn’t change anything it just started struggling at the end of it’s pull

I actually did a test for this - i’m not done sorting through data just yet, but it seems like you get the optimal force-per-distance-stretched at the start, when the rubber bands have been stretched just more than “a little bit” (around 15-20cm).