FlyWheel Prototype Help

[broluwo]

http://www.youtube.com/watch?v=hmgRfT4Kvxg&context=C3f259d3ADOEgsToPDskJH VJsffJdoRbm6llz3BmsI&safety_mode=true&persist_safe ty_mode=1&safe=active

Here is a video of our testing. It's not a close up, so we will follow up with a closer photo shot. The white back used is the back of regolith (used in 2009 Lunacy)

Thank you again!

[sdcantrell56]

Try more compression

[KrazyCarl92]

To understand how to prototype a flywheel design you should first understand the physics behind them. The fly wheel is intended to convert the angular momentum of the wheel to linear momentum in the ball. Ideally, the change in angular momentum of the fly wheel (decrease) is equal to the increase in linear momentum of the ball.

The formula for angular momentum is L = Iw, where L is the angular momentum, I is the moment of inertia (of the wheel in this case) and the w (actually omega) is the angular velocity of the wheel. The formula for linear momentum is P = mv, where P is momentum, m is the mass of the ball, and v is the velocity of the ball. Since the moment of inertia of the wheels and the mass of the ball don't change, we are simply concerned with the angular and linear velocities. Increasing the change in angular velocity of the wheels will in turn increase the change in linear velocity of the ball. One way to do this would be increasing compression between the backing and the wheels. This will transfer more of the energy stored in the angular momentum of the wheels to the balls, which is what you are looking for. The wheels should slow down significantly when the balls go through the shoot.

The more the wheels decrease in velocity, the farther the ball will go. More torque applied to the wheels via the motor will help with reload time (getting the wheels back up to speed after firing), but may not do much for increasing the distance or speed.

(My explanation above ignores the effects of angular momentum increase in the ball due to spin, but it still holds mostly true I believe.)

[broluwo]

https://mail.google.com/mail/?ui=2&ik=0c7da1b6d2&view=att&th=134d8e67d0e48399&a ttid=0.1&disp=thd&realattid=1390924362618503168-1&zwhttps://mail.google.com/mail/?ui=2&ik=0c7da1b6d2&view=att&th=134d8e67d0e48399&a ttid=0.2&disp=thd&realattid=1390924362618503168-2&zw These are the photos of our prototype. We'll try compressing it next, and then we'll try using less compression to see how well it works, and we will get back to you.

[jreuter]

As maddoctor said, it sounds like the wheels are already slipping through the entire contact with the ball. If I recall correctly, the force on the ball is the normal force x the dynamic coefficient of friction. Spinning the wheels faster doesn't change either of these. As someone else implied, increasing ball compression will change the normal force, and you should throw farther, with more transfer of kinetic energy from the wheels.

[WileyB-J]

Here's a picture of our current prototype. Check your compression and try not to alter the velocity/trajectory too much after it is past your wheel launcher, it tends to slow it down a great deal.

And this is it in action: http://www.flickr.com/photos/wileyb-...n/photostream/