Over-engineered T-Shirt Cannon

http://youtu.be/SpEfaHwq44s

Any specs on the cannon?
From the looks of it, it’s got some sort of powered tilt, and possibly a powered turret. Also looks like it’s on a human powered cart. Correct me on any of those accounts if I’m wrong.

Some specs for the cannon

Drivetrain:
-4 Four powered wheels, chain drive with 12:1 P80s
-2 Rotating Casters

Cannon Base:
-Custom machined rotating base with gear teeth around the edge
-Powered from the edge using Bane Bots 550 64:1
-Tilt using CIM + Bane Bots 108:1 P80 gearbox

Cannon:
-All the parts were either CNC milled or laser cut
-Barrel Material: 3" OD, .125" wall thickness aluminum tubing

Pneumatics:
-SCUBA air source (regulated to 140psi off of the low pressure port)
-Custom machined/welded accumulator tank (6" OD .5" wall alum tubing)
-1.5" air piloted Numatics poppet valve

We only have the single shot capabilities running right now, we are planning on having semi-auto belt fed capabilities as well. I have included a CAD rendering of the completed project. Our tested range right now is 75 yards.

http://jesuitrobotics.files.wordpress.com/2011/10/r1.jpg

Patrick Barone

Huh. A belt fed t-shirt cannon…now that’s a project I want to keep up with. And if it works out, then I’ll be selling some arms and legs to get a hold of the blue prints to build one myself. Either that, or get my hands on the materials to build a Team 254 Shockwave cannon.

Whoa!

It’s great to see a innovative bolt (or else something trivial), but to see something like this…it reminds me what our team could have done during offseason!

Just curious, why did you choose this particular design? Could you post your thought proccess of your decision between belt fed vs. 254’s gatling style reloading?

Eager for more,
Daniel

In our initial brainstorming, we had 2 ideas going on: 1. 254 style revolver or 2. a chain fed version. Really the only reason that we went with the latter was because it hadn’t been done before.

That is the true embodiment of innovation right there. “We went with [it] because it hasn’t been done before.”

It’s great to hear about teams going about projects from that angle. I hope it all goes well, and I’ll be looking forward to the updates!

The downside is that half the time the team ends up saying, “…and that’s why it was never done before.”

However, I bet it’ll work this time. I, too, cannot wait to see the results (I want my team to build a t-shirt cannon but I don’t think it’s in budget this year.)

Our senior members off to college encouraged us (we are more or less all rookie members) to build a t-shirt cannon. some basic ideas were drawn up, but were abandoned after we discovered that we are going to be hardpressed to raise the registration fee.

Still curious, exactly how would your cannon maintain pressure during a shot, if it is belt fed? Wouldn’t you loose most of your pressure through the belt slot?

Keep us posted,
Daniel D

I love how there’s clearly inspiration from the Poofs, yet it’s completely different all around. Impressive.

Not necessarily.

You could lock down around the belt.
You could build a belt that looks like O_O_O_O_O_O_O_O, where the O signifies a “cartridge” that has seals on the ends and a rolled-up T-shirt in the middle. That’s the basic premise behind Shockwave’s revolver section maintaining most of its pressure, IIRC.
You could fire at extra-high pressure. That’s a bit risky, though.

Yeah, either the belt could have seals or the barrel and valve could clamp on to the belt O shapes (signifying “cartridges”) via lead screws or something.

It looks like there is a CIM for rotation as well or is that just the CAD?

How long is the barrel?

On the upside, the team will have learned why it was never done before!

The mechanism should be obvious in this video…

http://www.youtube.com/user/MsDbarone?blend=2&ob=5#p/u/1/dUeHY40E5H4

Or rather in this video…

http://www.youtube.com/watch?v=aKuOWsHE6vI

To my knowledge, Shockwave has no seals anywhere in its cannon assembly - its rotating barrel carrier (powder coated aluminum) butts up against the fixed rear of the cannon (lexan), and this interface maintains a very small gap (1/32" or so, if I recall) during barrel rotation and cannon firing. This small gap limits the amount of air leakage at that interface during firing. It is a very simple system and works very well.

I have no idea why I’d know all of these details offhand. :wink: