Flywheel Compression and Launch Angle

In Turning Point, my team and I built a flywheel to shoot the 3" balls and had the flywheel slowly “decompress” as the ball went out. It entered the flywheel with a relatively higher amount of compression than it exited, i.e. it slowly decompressed (not fully) as it went through the flywheel.

Is there an appreciable difference between flywheels that have constant compression (consistent distance between the flywheel and curved polycarb) and flywheels that slightly decompress as the projectile goes through?

Here’s some of the cad I currently have:



Second Question:
I’ve noticed that flywheels with a perfect 90-degree curve don’t launch the discs perfectly straight ahead. The disc flies out at a few degrees to the left or right, depending on the build. Does anyone know a definitive answer to how many degrees you have to reduce the hood angle (<90) to make the disc fly in a path parallel to the robot, or is it something that I’ll have to experiment with?


both compression and hood angle are the sort of things that you’re going to want to tune on your robot, these interactions are too complex and variable to get right with theoretical means.


It is important to note that Turning Point balls were made of rather rigid plastic and most of the compression had to come from the flywheel surface material and hood.

I believe that for the long range shooting of the foam compressible object, it is most important to tune the compression at the exit point and that the length and compression along the rest of the hood is not as critical.

In fact, if you want to reduce the energy losses due to the compression and rolling resistance friction of the foam disk, you want to have as little compression as possible along the hood - just enough to make sure that the disks don’t slip and stay engaged with the flywheel while they get to the final launching position. Rubber bands or foam strips may serve as good material for the hood.