5842Z CAD reveal

okay after building everything and modifications to a few things, you weren’t wrong. it sucked trying to get it to work. but, it works now.

Where would you put the rubber band in order for the catapult to launch the disks? a diagram would be helpful, thx!

depends on your design. I don’t recommend copying this robot as it isn’t the best, I do recommend seeing this design and innovating it to your ability tho. build something that comes to your mind. it’ll be so much better in the long run.


In very basic terms, find two points that are close together when the catapult is in its fired, or more vertical position (what it would look like after its fired a shot), and far apart when the catapult is in its primed position (what it would look like before its about to shoot) and then put your rubber bands across those two points.

Okay, that makes more sense, thank you! also do you have to use pneumatics made/sold by vex, or can you buy a similar one online?

All questions regarding legality can be answered in the game manual:



Use vex sold pneumatics but catapults can definitely be made without pneumatics

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Okay big update, robot is fully assembled, and we got to full testing yesterday, turns out some unseen issues were found, (compression, other random things) but we already got to work this morning. intake has been given a little modification to work better with our steep intake ramp, and it works much better. our string shooters aren’t doing exactly what we thought would happen due to previous testing, and we need to mod those a little to be more, violent, but in a safe way of course.

when it comes to drivetrain and color roller those work absolutely perfectly.

as much as I hate to say it, cata is having the most issues and it’s just relatively jank which disappoints us, but it’s our fault and there’s no one to blame but us.

wish us luck as we have about a week and a half until our first comp. we still don’t have auton :skull: I’m not worried about it this year tho as I’ve have about 3.5 years of programming under my belt, and have almost perfected our strategy for auton programming.

otherwise, we (once again) wish everyone luck in spin up!


What’s the advantage of having a steep intake ramp and steep disc loading well/bucket?

no advantage really, its just what fit our design constraints.


Can you show me some pictures of your robot? We’re gonna build a catapult and just want a reference, we cant find any good pictures of spin up catapults. A picture of the intake and catapult mechanism would really help us.

there’s CAD files wayyyy above for a reference. using those pictures should give you the ideas youre looking for. also there are plenty of catapults that are referenced on youtube. big ones being 3759x, 6627a, 248c, 229v… just to name a few

edit: I can’t believe I forgot 80001B and 1569A. huge starters of cata gang, that YouTube video even holds the precious comment of “if a cata bot wins worlds I will eat a spin up disc”


Do you have any tips for finding the right amount of teeth to shave off the slip gear?

take the time that’s necessary, first things first, find the launch angle that scores from where you want on the field, this includes distance, height, and consistency. then, introduce your gear, and shave groups of teeth til it starts getting closer and closer to where you want it to release, then start shaving 1 tooth off at a time. it’s really just putting the time that it requires into it.


How many teeth did you shave and how many teeth did that motor have?

it’s a 1:3:5 ratio. teeth shaven depends on your design

Oh okay and one more question, why do you have a 12T gear (i guess) connected to the shaved gear, which is connected to another bigger gear? I understand how catapults work but just wanted to know why you wouldn’t connect the motor to the shaved gear.

The 12 tooth is the powered gear, and it’s not directly connected to the shaved gear, there’s a non shaved gear that the 12t is connected to.

How’d this go?


it went a little rough actually. we went undefeated for our first 3 quals, won the 4th point wise but got dq’ed because I shot endgame outside of the field, no one was injured thankfully, and lost the 5th qual. landed ourselves in 12th seed, ( we were in between 5th and 7th until the last 2 quals) got picked by 3rd seed, and an unseen issue with our catapult caused us to have an upset and lost in the quarter finals. overall, it was a good learning experience for this robot, and we have about 2 pages of notes we took for our own robot containing possible improvements, strategy changes, inconsistencies, and things that just need to be totally redesigned. I’m disappointed as we walked in with quite a lot of confidence and I felt very good with how the robot would perform, so when things started to go totally wrong it was frustrating. but there’s no one to blame but us, we just need to improve.

Edit: forgot to mention we set the high score match of the comp at 143-34.