3481's Summer Design Comp Submission

I’d like to present my team’s submission for the summer design competition:
Nimbus 3481

(pictures at the bottom)


  • 8 wheel drive with a .125in drop
  • 4in Colson wheels
  • 3 CIM 4 speed gearbox: 17.00fps, 12.71fps, 7.36fps, 5.51fps (adjusted)
  • #25 chain driven with spring loaded chain tensioners


  • intake loaded speed: 36.4in/s
  • three positions: inside frame, wall feeding, ground pickup


  • max shooter speed: 2511rpm
  • max ball speed: 43.83fps / 29.88mph
  • shooter angle range: 0deg - 45deg
  • full court shot runs at max speed and a 29.5deg angle
  • turret has a full 360deg of rotation

This project started off as a team effort, so our strategy and general design decisions are team decisions. However, most of the group members couldn’t do their part of the CAD due to other commitments, so I took on the intake, tower, shooter, and control system in addition to my initial subsystem, the drivetrain (so everything you see right now).

The back of our robot looks really open. That’s because this is where we’re going to put our endgame mechanism that my mentor is still working on. Even though it was not finished in time for the submission, it’s been of great value as my mentor is learning CAD for the first time and has learned a lot from this project. The mechanism is used to reach out and pull the snitch into the robot during the endgame as we’re chasing it around the field at 17.00 fps.

You might notice the overwhelming lack of fasteners. Great. You have eyes.

Here’s link to the summer design comp thread: http://www.chiefdelphi.com/forums/showthread.php?t=137404&highlight=quidditch

Here’s a link to thread about my 4 speed gearboxes in case you wanted to say how overkill it is: http://www.chiefdelphi.com/forums/showthread.php?t=137726

Some faults that I did notice but didn’t have time to fix before the submission:

The tower is powered by a BAG on a versa planetary that is under the tower so it might be a little hard to see. The belts are set up in a way such that one side of the tower will go up and one will down. When I go back and fix it, I’ll add another idling pulley that is geared 1:1 with the pulley on the motor in order to get the clockwise and counter clockwise spins.

Also, the cams on the hood will probably break off under the force from the compression of the ball and its inertia. I’ll need a stronger way to mount those servos.

I also wanted to add a gate mechanism that would allow or block the balls from getting into the shooter while the tower is running.











so yeah, lemme know what you think