Over-engineered T-Shirt Cannon

[CalTran]

Originally Posted by baronep

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!

[Ninja_Bait]

Originally Posted by CalTran

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.)

[daniel_dsouza]

Originally Posted by Ninja_Bait

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

[EricH]

Originally Posted by daniel_dsouza

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?

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.

[Trent B]

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?

[Fireball9199]

How long is the barrel?

[Travis Hoffman]

Originally Posted by EricH

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.

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.

[ajd]

Originally Posted by Ninja_Bait

The downside is that half the time the team ends up saying, "...and that's why it was never done before."

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

[baronep]

The mechanism should be obvious in this video...

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

[baronep]

Or rather in this video...

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