2583's prototype shooter
 

http://youtu.be/fgzBNZLNgLQ

Here is a link to the prototype that we made today
The basketball court that we are shooting across is about 50 feet and we are hitting the center of a backboard everytime with less than a foot of variation

Re: 2583's prototype shooter
 

Pretty Impressive! What's your motor setup?

Re: 2583's prototype shooter
 

Under that 6 inch KOP wheel is a CIM directly hooked to it

Re: 2583's prototype shooter
 

Yeah I had no doubt I'd be seeing some pretty impressive thrower designs this year, I just didn't expect them this quickly! Keep it up, guys!

Re: 2583's prototype shooter
 

Either that's a 2009 wheel, or it's the 4" KOP from this year..?

- Sunny G.

Re: 2583's prototype shooter
 

It's actually one of the 6 inch white Hi Grip wheels that came with this year's KOP drivetrain

Re: 2583's prototype shooter
 

Really? Intense.

Also, are you sure that's 50 feet? It looks more in the range of 25-30 feet, but it could be the camera playing tricks on me.

- Sunny G.

Re: 2583's prototype shooter
 

Yeah its about the size of an FRC field, its probably the camera angle and the fact that the guy is pretty tall

We wont be shooting that far in the game and over about 20 or 30 feet is it very highly accurate

Re: 2583's prototype shooter
 

Really nice! Have you guys tried shooting at a higher angle?

Re: 2583's prototype shooter
 

i am having the same question as this guy im wondering if you put it on an angle will the frisbee have a different reaction?

Re: 2583's prototype shooter
 

I think you guys may want to try and amp the power up a bit, for increased range.

Otherwise, bang up job!

Re: 2583's prototype shooter
 

How much compression do you have on the disk?

Re: 2583's prototype shooter
 

How high was the shooter off the ground?

Re: 2583's prototype shooter
 

What material is your clear wall made out of? Polycarb? Plexiglass? Something else? And what is it's thickness? I'm just surprised that whatever material you are using can bend so easily.

Re: 2583's prototype shooter
 

That is a good question and if you watch the video closely you will see the clear wall moving as the frisbee goes by. I am just guessing but once that wall becomes fixed your results will change and I'm thinking not for the better, but who knows, I could be wrong.

Re: 2583's prototype shooter
 

What was the RPM of the CIM? Was there any reduction off the CIM, or was it straight direct dirven off of it? For this prototype, was it just battery->cim->wheel->frisbee?

Re: 2583's prototype shooter
 

To answer a few questions

The shooter was about waist high, so 3 or 4 ish feet off the ground and it was angled up with just a 2x4 under the front

The wheel is direct driven by the CIM and just directly hooked to a battery. I believe this leads to around 4000 RPM

At first we cut the wood circle and placed it exactly 11 inches away from the wheel
Then we added two polycarbonate sheets, each 1/8 in thick to the inside of the curve. So we ended up with only about 1/4 in of compression

We were wondering how changes in RPM vs compression would change the trajectory and we found that using a half dead battery, so a lower RPM, the frisbee only flew marginally less distance and was stills table. However, removing just one 1/8 in sheet of polycarbonate caused the frisbee's range to drop from 50 to about 10 feet.

We will be trying a higher angle soon, however based on other videos, including the Robot in 3 Days robot, shooting at a higher angle will still work

Re: 2583's prototype shooter
 

What wheel did you guys use? It looks like a lunacy wheel.

EDIT: I read the other posts more carefully, it's a 6" KOP wheel from this year. Sorry for not reading.

Re: 2583's prototype shooter
 

Once up to speed, the only external load on the CIM is windage and vibration due to unbalanced wheel. At 12 volts and 4000 rpm, the CIM would be drawing 34 amps and generating 250 watts of output power at the shaft. If you guys have a clamp-on ammeter, it would be most interesting to see what the current draw actually is.


Not sure what you mean by a "half dead" battery.

Do you plan to do closed-loop control of wheel speed? If so, when you get the speed sensor mounted you could provide some useful data to the CD community showing how rpm affects the frisbee flight path.

Re: 2583's prototype shooter
 

I'd love to see some useful data too!

Re: 2583's prototype shooter
 

here is the second version of our frisbee shooter

We have our CIM directly mounted to a 6 inch White KOP wheel from 2013

The wall is two pieces of 1/16 in sheet metal mounted at two points causing compression of about 1/4 in

We are shooting at a 30 degree angle, and the axle of the wheel is 120 inches from the Alliance Wall

This is around where the base of the pyramid is because our plan is to back up into the pyramid so that we always have the same position, similar to how teams used the fender last year

http://www.youtube.com/watch?v=EjK6m...ature=youtu.be

Re: 2583's prototype shooter
 

Is it just me or does it sound like your wheel is experiencing some fairly drastic slow down?

- Sunny G.

Re: 2583's prototype shooter
 

This could be the reason, no speed control:
...and no headroom for speed control unless the shooter is reconfigured so that the CIM needs less than 12 volts to maintain the desired operating wheel speed.

The flexible curved guiderail is an interesting concept; first video I've seen of such.

Re: 2583's prototype shooter
 

We use a curved guiderail, we found that it icreases our accuracy significantly. I plan on releasing a video later today along with some test results. For now you can see some slow motion shots we took last night at the very end of this video. It also shows three shots and where they landed about 25' away.

https://www.youtube.com/watch?v=Orsk...e_gdata_player

Re: 2583's prototype shooter
 

Many teams have prototyped, and have posted videos of, shooters with curved guiderails.

My post was referring to a flexible curved guiderail. Watch Team 2583's video again, and pay close attention to the guiderail.

Re: 2583's prototype shooter
 

Sick, Lets see the hopper/feeder system now :D

edit: Do you have any sort of guide system on the shooter? Ie. Something to restrict the movement of the Frisbee to one path each time you shoot?

Re: 2583's prototype shooter
 

thanks for adding entertaining pop-ups. That made me watch until the end so I could discover you guys also have time to build an ominous rube goldberg device!

Re: 2583's prototype shooter
 

How is your motor holding up? We burnt out the bearings on a mini-CIM with a similar wheel attached directly to it's shaft.