Posted: 09/08/2007 0:20 AM Post subject: high velocity burst disc 6mm pneumatic
space monkey
Joined: 15 Mar 2007 Posts: 7050 11306.91 Spud Bux
Not sure if this should be in the hybrid section, as that's what I intended this project to be - here's the original design idea, but I was doing some routine air testing and this was the velocity (according to my Combro CB-625 that has been tested against other chronies at over 1300 fps so I have no reason to doubt the result) I got for a 0.12 gram BB
I was trying to see at what sort of pressure different discs would burst, and quickly discovered that across a 6mm diameter area, it's pretty high. With a single layer of ordinary transparent tape, it held right up to the maximum pressure I could give it with my shock pump (around 400 psi) and only burst when I unscrewed the fitting slightly. I ran a BB through the chrony and got 1032 feet per second, so I tried again, hence the above result
I was going to try it as a hybrid but to be honest I think I'd rather do some more high pressure air tests for now. Here's the completed breech with an inch tape for scale:
It's interesting that in spite of the smaller chamber than the final version of my HVBB project, the velocity with 0.12 gram BBs is much higher - clearly some sort of valve bounce is the problem. Enough of that, I have more holes to make
As always, for more detailed information on using epoxy, check out the how-tos here and here.
As usual (honestly, when will I ever learn?) I've put it under too much strain and it's sprung a leak. I've removed the rear section, screw the hybrid, I'm rebuilding it as a pure pneumatic for high speed testing.
As usual (honestly, when will I ever learn?) I've put it under too much strain and it's sprung a leak. I've removed the rear section, screw the hybrid, I'm rebuilding it as a pure pneumatic for high speed testing.
oh well its very impressive for a pneumatic and i would love to see a video of it shooting
good luck with fixing it and getting it to shoot faster and better
Joys of living in Europe 9/32" is around 7mm, so it could be close. Best thing is to take a vernier caliper or actual BB with you to the shop to see what fits well.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You cannot attach files in this forum You can download files in this forum
