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
Pretty Impressive! What’s your motor setup?
Under that 6 inch KOP wheel is a CIM directly hooked to it
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!
Either that’s a 2009 wheel, or it’s the 4" KOP from this year…?
- Sunny G.
It’s actually one of the 6 inch white Hi Grip wheels that came with this year’s KOP drivetrain
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.
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
Really nice! Have you guys tried shooting at a higher angle?
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?
I think you guys may want to try and amp the power up a bit, for increased range.
Otherwise, bang up job!
How much compression do you have on the disk?
How high was the shooter off the ground?
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.
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.
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?
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
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.
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.
I’d love to see some useful data too!