My team is having a hard time creating a stable structure for the catapult, as our catapult is very wide, due to the large/wide drivetrain.
Sometimes the catapult is too long and doesn’t meet height requirements for inspection, sometimes it’s wayyyyy too short, and almost every single time, it does not have the power to shoot a goal.
After searching on YouTube, we found that our robot resembles this one the most: https://www.youtube.com/watch?v=rF0EgTK5iTw
However this video uses a choo choo, not the thread mechanism on Swish.
Does anyone have any idea or guidance on making a stable structure for catapult, state is in 2 weeks, and we have no other robot than this one. We’ve been stuck on this for a while now.
A picture of your current robot would help. Here are some things to think about for this year (and next)
Connectors and pins are your friends, use lots
0x pins (the ones with caps on them are your best friends
(my favorite is 0x3 pins, I use them to connect 2 parts together and then put a 1x1 beam on the end to lock it in place.
Sometimes doubling up on connectors gives you extra pins, which means extra strength. For example taking the 228-2500-126 Large Chassis Corner connector, putting it back to back with 0x2 pins gives you an extra strong corner connection for your chassis and superstructure.
If something comes apart when you don’t want it to, add pins.
Triangle braces help keep things square.
All wheels do not need to be driven.
Making channels out of a pair of 2x parts are good for chassis frames.
Wheels should be inside of channels so the axles are supported on both ends.
Using a “stopper bar”, which is an axle across the motion of the catapult arm has two benefits. One is that it keeps your arm from exceeding the height requirements. The second is it acts like the snap of the wrist in releasing the ball.
If your catapult is a first class lever (fulcrum or pivot is in the middle) a good rule of thumb is for every 5 holes on the load side (where the ball is) have one hole on the effort side (where the rubber bands are)
Game reveals are done in May, so ask for help or ideas before the 10th of March.
Can I see some pictures? Your problem might be that your rubber bands in the back are not strong enough to shoot high. That’s just a guess, but that problem happened to all of the teams in my school except for 1, so that might be it.
Google “Build a 1-Motor Choo-Choo Catapult”, it is by team Chewbotca 7163B. There is a printed guide and a video. A few teams built them and it works well in both the high and low goals. It’s only the catapult part, you need to add a base.
