Okay, would you happen to know of a good link that i could learn how to do that? that would really simplify the design.

Also, thanks for the CAD image. it's really sparked some ideas

I would make it delrin or nylon only. No need for sealing rubber at the pressures you are going to provided all the surfaces are true. Also, I wouldn't bother with o-rings or equalisation holes. Just make it a tight fit and you're good to go.

good to hear, that would simply the design. and make ...

Alright. By the way would a nylon piston work for this? its a pain in ass to lathe, but it would be lighter and more shock absorbant

Sounds good.

Moonbogg, I don't have a pipe threader that large, to i might have to keep the shear bolts for now unless i can redesign it to include tie rods.

Thanks for the pic jack :wink: I think i might actually be able to get some helium. The tangential chamber is actually 18" long, it just ...

Thanks, is there a minim length needed for the barrel seat tube? some of the tutorials I've watched say to keep it centered of the air chamber for some reason.

I'd start with an aluminum cylinder lathed to a point a few inches long.

Yes it is :wink: for testing I'd probably just load through the ...

This is the design for the core component of a high pressure launcher I’m working on. It's a basic barrel sealing piston valve, except it's designed for much higher pressures than normal. The goal is 1000psi, and the sound barrier. :D

If any of you see something that could be improved, or ...

Yes! thats the equation i needed. it comes out to be 1359lbs, which sounds about right

Wow, thanks for the full explanation. :D
Also, very helpful calc MrCrowley

So if i have a 2.6lb piston in a 4" chamber and 1.3" stroke at 1000psi, that would be:
a = P*A/m, or 1000*12.56/2.6 = 4833 in/s^2 = 402ft/s^2

Then d=0.5at^2, or 1.3=0.5*402*t^2, so t=0.0804s

Then Vf= a*t, so 32.33ft/s ...

Im sure these are on this site somewhere, but i havent exactly found what im looking for. does anyone know some links or formulas off hand that could help be predict piston force as well as projectile velocity or acceleration? I know the basic physics calculations with velocity/accel/distance/force ...

MrCrowley, that's pretty interesting actually.. and yes i do :P

The tank was bought new(empty) and was filled with compressed air from a local scuba tank supplier. (on a side note, this is a nice way of filling a tank to 2000psi for 10 bucks, compared to paintball fillers)
This is not the first ...

True
Alright, good to know. Thanks for the advice!

i am going to remake it, but here is an example of many more pins being used effectively. http://www.youtube.com/watch?v=75O71AHTIr4

The Proof strength of the screws is roughly 25,000psi. The shear strength tends to be 60% of that with most steels, so with the diameter of the 1/8" screws they can each hold about 184lbs in shear force before they start to yield. times that by four, and they have enough to withstand the 628lbs of ...

what do you mean by tear out? if not the screws, as in the fitting coming off? And yes, the screws do blow out at 250psi (not force) since they are not fully 'screwed' in. the holes were drilled first with 2 different sized bits so that the screws would only have a few threads to grab onto, putting ...

The manufacturer is Charlotte Pipe, but i could not find the manufacturer specs. Theyre out there somewhere, i just got tired of looking so i found this resource from engineering toolbox to have a nice estimate. I tested the pull out of the screws with weights, then calculated the psi required to ...