We have used the cho cho mechanism but the kids want a dual catapult design. (I am no help) any ideas for them to look at? We looked at Ben Lippers robot but can’t understand his catapult design. Thanks in advance

1 choo choo, 1 arm with 2 spots for a ball to sit before launch

We have the same problem as you. My kids designed their arm but can’t figure out the gearing to make it work.

I made mine work essentially with two 24t gears on the motors to 48t gears on the catapult. The layout can be a little tricky, so I’d suggest also using this video as a guide. I also made a robot reveal for the catapult robot if you wanted to see more of how it worked. For further guidance, you can…

FRC973 has some good designs, basically what you want to have is 1 choo-choo mechanism in the middle and essentially two arms linked together horizontally to hold 2 balls at a time.

Interesting I’ll tell the team and see what they think. Thanks

We are having trouble with the gear popping out any help guys [image]

In the Vex IQ VEX IQ Builds - Fling they use double gears and a 1x to lock it in place. [image] Edit: Adding reference link: https://content.vexrobotics.com/docs/21-22/pitching-in/Fling-BI-Rev2.pdf#page=29

In addition to what @Hudsonville_Robotics said, I would suggest getting rid of the orange spacer between the gear and the beam to make it flush with the beam, providing the most support for your catapult. Also, make your the teeth on the gears are aligned and not skipped.

So they got the twisting of the gears but now the linkage for the Choo choo keeps coming loose any ideas?

Can you be more specific? A picture / video would be really helpful.

Dual catapult help

VEX IQ General Discussion

SCFarrell November 7, 2021, 10:43pm 12

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