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-   -   pic: Wheeled shirt launcher (http://www.chiefdelphi.com/forums/showthread.php?t=144885)

Taylor 28-09-2016 08:57

Re: pic: Wheeled shirt launcher
 
Slight resurrection, but I'm curious - has your team moved forward with this project?
We are also looking at wheeled t-shirt launcher designs as an offseason project (and practice for the upcoming American Football game), and there simply aren't many to be found.

D.Allred 28-09-2016 14:59

Re: pic: Wheeled shirt launcher
 
Quote:

Originally Posted by Taylor (Post 1609258)
Slight resurrection, but I'm curious - has your team moved forward with this project?
We are also looking at wheeled t-shirt launcher designs as an offseason project (and practice for the upcoming American Football game), and there simply aren't many to be found.

We built one last year similar to the OP's design with a few key differences. We used a cylinder to push the shirts into the wheels. We also had a pvc pipe on the shooter to keep the shirts straight. There are slots in the side of the pipe for the shooter wheels.

Here's a brief tour of the shooter.
https://youtu.be/SnaXhoxGsy0?t=8m1s

What information do you need?

David

Taylor 29-09-2016 14:25

Re: pic: Wheeled shirt launcher
 
Quote:

Originally Posted by D.Allred (Post 1609304)
What information do you need?

At this point, we are most interested in your launcher wheel RPM and the optimal compression on the shirts. I think we can puzzle through the rest.

Chris is me 29-09-2016 14:50

Re: pic: Wheeled shirt launcher
 
2791 briefly built a prototype of a wheeled T-shirt shooter in late 2014, and I think they found that marshmallow wheels ("Sure-Grip Drive Rollers" on McMaster, Buna-N) were the best wheels for shooting T-shirts. The compliance helps deal with small variances in shirt packing density or size, and it imparts more energy into the shirts. I would give those a try.

inorbert 29-09-2016 17:09

I need to get pictures from my teammates but 5811 built a t-shirt shooter prototype and were able to get roughly 38 yards out of it. We used 2 6" andymark wheels with 2 timing belts to feed into it

Sent from my LG-D851 using Tapatalk

nuclearnerd 29-09-2016 23:05

Re: pic: Wheeled shirt launcher
 
We built the a test version of a wheeled shooter this summer with Andymark 8" wheels, and VEX clamping gearboxes. See here: https://goo.gl/photos/hjbNw8vYjDLF34nG9. After a bit of iteration (added a second stage, and reduced compression to only about 1") we got it shooting about 75 ft. There's still a bit of work to do before we can mount it on a robot (and I think we can tweak it to shoot further) but we might use the test version as-is as a "T-shirt mortar" into the stands at this fall's STEMley Cup

roboruler 29-09-2016 23:30

Re: pic: Wheeled shirt launcher
 
For something like this, it would probably be a lot better and cheaper to buy some Brushless outrunners and brushless ESC's rather than try to keep to FRC legal parts only. Your spinning a flywheel in one direction at highspeed so it's basically perfect to be made Brushless.

Chris is me 30-09-2016 09:36

Re: pic: Wheeled shirt launcher
 
Quote:

Originally Posted by roboruler (Post 1609535)
For something like this, it would probably be a lot better and cheaper to buy some Brushless outrunners and brushless ESC's rather than try to keep to FRC legal parts only. Your spinning a flywheel in one direction at highspeed so it's basically perfect to be made Brushless.

It really wouldn't, though. Even assuming they don't reuse old parts, a CIM is $27 and a Spark is like $45, which together is comparable to or cheaper than a 12V 300W brushless motor. You can get non-reversible PWM speed controllers for brushed motors for less than the cost of common FRC reversible controllers.

Edit: I didn't see they were feeding the CIM through a VP, which I honestly think they could skip if they wanted and just cantilever the wheels off CIM shafts with hex adapters. Kind of sketchy but it would be fine for an offseason robot.

Andrew Schreiber 30-09-2016 10:49

Re: pic: Wheeled shirt launcher
 
Quote:

Originally Posted by roboruler (Post 1609535)
For something like this, it would probably be a lot better and cheaper to buy some Brushless outrunners and brushless ESC's rather than try to keep to FRC legal parts only. Your spinning a flywheel in one direction at highspeed so it's basically perfect to be made Brushless.

I'm gonna ignore the cost argument. But I'd have concerns if your shooter wheels had any significant mass. There'd likely be some reconfiguring of the ESC required to get it working without starting a small fire.

DC motors can be abused and, given how students tend to do things, that's a good thing. I'd stick with maybe some 550 motors and appropriate VP gearboxes if required.

NWChen 30-09-2016 17:00

Re: pic: Wheeled shirt launcher
 
Quote:

Originally Posted by Taylor (Post 1609258)
Slight resurrection, but I'm curious - has your team moved forward with this project?
We are also looking at wheeled t-shirt launcher designs as an offseason project (and practice for the upcoming American Football game), and there simply aren't many to be found.

We (the two of us, no longer our team :) ) have achieved 60-70ft running 6" Colsons directly off MiniCIMs. Compression is a huge factor. Refer to this thread for more information:
https://www.chiefdelphi.com/forums/s...d.php?t=149446

Video should be up soon, since we'll be at Maker Faire NY this weekend.

Sperkowsky 30-09-2016 17:20

Re: pic: Wheeled shirt launcher
 
Quote:

Originally Posted by NWChen (Post 1609689)
since we'll be at Maker Faire NY this weekend.

See you there! Will be very interested to see what you built in action.

inorbert 02-10-2016 06:04

Re: pic: Wheeled shirt launcher
 
Took a bit but here is ours, you cannot see where the t-shirt lands but it is about 115 feet away. The front two wheels are each powered by a CIM and the belts in the back are each powered by a Mini CIM. We couldn't keep testing because we lost the key to one of the mini-CIMs and don't have any extras

NWChen 02-10-2016 13:52

Re: pic: Wheeled shirt launcher
 
One of several videos from Maker Faire. We estimate about 70ft in the air. The compression of the shirt is very important (our best shots were made with very tightly rolled shirts).


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