Second FIRST Ball Launcher

[generalbrando]

My students set out today to make sure that it was possible to make the ball fly as far as we wanted. I'm sure we're not the first, but here's their work in video form (1.6 MB).

Basically we just hooked up a small CIM to a controller set so that we could control the speed. Then, in compelte disregard of safety, we pushed the wheel to full speed.

That's the 12.5" pneumatic wheel from the 2004 kit. It was spinning at an estimated 3000 rpm. The motor doesn't actually take that long to reach full speed. We were letting it ease into the high speed because we didn't machine the setup, so it wasn't best to test all limits.

Most of the force going into the ball is provided by the inertia of the wheel - not the motor. The motor loses speed after firing the ball, though it doesn't take much time to recover.

We know this is faster than 12 M/S (estimated 20 M/S based on slow-mo frame counts), but at least now we have a problem of going to fast rather than too slow.

[techtiger1]

http://www.badongo.com/vid.php?file=...56.MPG&s=black
This is Our prototype type shooter pretty simple took two days to construct. Have fun everyone feedback please.

-Drew
Team 1251 the Techtigers

[KenWittlief]

Originally Posted by generalbrando

My students set out today to make sure that it was possible to make the ball fly as far as we wanted. .

ok, fess up! you were targeting the florescent light, werent you?

(very cool launcher! :^)

[Andrew Blair]

Oh man, I was waiting for that wheel to fly off! When it got up to speed the fins really got a wizzing. Well, thats one more thing to take off the "Possible Flywheel Options" list.

[Rick TYler]

Originally Posted by generalbrando

That's the 12.5" pneumatic wheel from the 2004 kit. It was spinning at an estimated 3000 rpm.

[petek]

The thud you just heard was made by the game designers when they hit the floor after fainting. You guys must have missed the Kickoff opening segment on safety! Nice way to remove ceiling tiles.

[KTorak]

Wow. I can only imagine 5-6 robots on a field firing balls like that, lol. 3000rpm is ALOT....and pretty dangerous, I can tell that they will be very picky when it comes to passing in Inspection (probably will want a safety gaurd [lexan] all the way around anything that moves at a high rpm like that).

[generalbrando]

My students may be reading this, so I don't want to put a damper on their parade, but we're going to scale back that thing a lot

It's unsafe, too powerful, and too big. However, they were looking for proof that they could actually launch the ball far enough. We kept asking them "ok it looks cool on paper, but how fast does this need to go? how much torque? how big of a wheel?" until they decided to build a prototype and test it. This thing only took a few minutes to build and we only launched the ball twice. It's now decommissioned

[FreakyAntelope]

Originally Posted by generalbrando

It's now decommissioned

[Schneidie]

That was probably targeted at the light, and while it ws a good idea, it was probably the most unsfe test I have ever seen.

[sanddrag]

We are thinking of two 8" wheels each weighing about a pound and each powered by direct drive off of a big CIM. Talk about scary!

[Kyle Love]

Is that thing going 12m/s^3 ? That thing was flying!

[Doug G]

Here's another type launcher again using CIM's with 2.67 reduction...

Link to the MPG video at our website...

Still not real sure if that's the way we'll go yet, but who knows...

[KTorak]

Originally Posted by Doug G

Here's another type launcher again using CIM's with 2.67 reduction...

Link to the MPG video at our website...

Still not real sure if that's the way we'll go yet, but who knows...

Shame, shame, where's the saftey glasses? Otherwise, that seems like an interesting mechanism. My team still hasnt finalized our design, but we know where we want to go with it, and what we want it to do.

[generalbrando]

For the record, it wasn't targeted at the light. We did two test fires. The second one you saw. The first hit the wall 3 ft below the ceiling. This difference is obviously due to holding the plate in place rather than mounting it. The ceiling looks damaged in the video, but it's not. The panel popped up and we put it back in. We did more damage with the tetras and our robot arm last year.

So again, while I emphasize that I agree this was not safe, I'll argue two points: We took our time reducing safety hazards and we made this prototype and posted the video here for the benefit of everyone knowing that kit parts can do launch the ball effectively. Diagrams and math are great, but we rest easier at night knowing that we won't build a complex mechanism only to have the ball go no more than 5ft.