[FTC]: Help with shooting mechanism?

[Rick TYler]

I believe the simplest solution is to spin two 4-inch wheels on the same shaft, and shoot the ball "over the top" with a guide plate or rails. "Hot Shot" is a derivation of the 2006 FRC game "Aim High" and that was a popular, simple design. You are going to spend on extra gears, though, as you will need to gear up the motor speed quite a lot. Our FTC robot is using a pair of 12-volt motors driving a 27:1 ratio gear train spinning the wheels. This system is too "hot" -- shooting a ball both higher and farther than legal, so the students will be slowing it down either in software or different gearing. Comments here on the forum have indicated that 18:1 can work.

One of the keys to shooting a ball with a single wheel launcher is to provide some kind of pressure plate or rails to hold the ball against the wheel at the moment of release. You can achieve this by having two wheels aligned vertically and spinning in opposite directions, but this adds weight and complexity and takes up a lot of room on what is a pretty small robot. I'm sure teams will make it work, but a single wheel (or dual wheels like on a big Ford or Chevy pickup) is easier to engineer and will work just about as well.

Good luck.