SpudFiles

this weekend it was raining and i went to the hardware store to buy some supplies for a new cannon. i had never made a burst disk cannon, and wanted to try one out.

everything is currently 3/4". the chamber is 12" long and the barrel is 36" long. i use thick aluminum foil for the burst disks and pressurise the primary chamber to 80 psi, and the secondary to 20 psi.

i was originally going to have a 2" by 12" chamber, but my hardware store was out of the proper couplers

and here are the images

smart design iv never seen it before tho

great gun

i was going to paint it but it has been raining

Very nice looking gun and a unique design! Can't wait to see it with a paint job!

have half days right now... just painted my other gun

post them up in a sec

You should use some hose or some fittings so the blowgun vents into the barrel. Someone (might have been killagorrila) said they made a sprinkler valve's blowgun vent into the barrel and it significantly improved performance.

really?
hmm. might have to try that out this weekend.

Oh and whats the C:B ratio on that?? Looks like the chambers too small.

looks nice, if i ever make a burst disc cannon, it would be like that one.

Insomniac wrote:Oh and whats the C:B ratio on that?? Looks like the chambers too small.

The c:b ratio is 0.333:1 the most EFFICIENT c:b ratio for a pneumatic is 0.2:1 but the most powerful is 1:1 or higher, so adding a larger chamber would increase performance, ALOT!

medievalman wrote: The c:b ratio is 0.333:1 the most EFFICIENT c:b ratio for a pneumatic is 0.2:1 but the most powerful is 1:1 or higher, so adding a larger chamber would increase performance, ALOT!

I've been waiting for someone to bring this up since I posted my own C:B ratio on my pneumatic and then thought about it for a bit.

A ratio can't possibly be the same for all cannons. A cannon running on 60psi has to have a vastly different optimum ratio to one running at 200psi because of the difference in the stored energy.

With a 1:1 ratio in both cases the first would have 30psi behind the projectile as it left the barrel and the second would have 100psi behind it.

ya, im aware that the CB ratio is really small. it was going to have a 2" chamber, but they were out of the proper couplers.

before you paint it, you should get a 24" long 1" chamber. and why is it sch 80 pipe? sch 40 is plenty strong for pneumatics and combustions, just not hybrids

its sch 80 because its threaded on both ends at my hardware store. and the unions are sch80...because they are....im going for a 2" by 12" so the same thing

so, why is there 2 diffrent burst valves. is it so you can get higher pressures. Because i thought that maby between the burst valves the the 80 psi gets relief on the foil because the 20psi on the other side? is thais what it does?

Its so he can trigger them instead of waiting and praying for it go boom once it hits the burst discs pressure.