Pneumatic Cannon Design - Could this work?

[Doctore]

Hello everyone. This design just popped into my head and I had to draw this.

The design is very simple and self explanatory. It combines principles both of pneumatic and a hybrid cannon (bursting aluminum disk), but in this case aluminum disk is pierced with a sharp rod as you can see.

I guess you could use a hammer or something heavy to strike the rod. My biggest concern is that aluminum disk would not fully rupture and that pressure would escape through a tiny hole made by this sharp rod. I cannot predict what would happen if you pressurize it to 300+ psi.

Tell me what you think guys. Could this work? Would aluminum disk fully rupture or at least, would the hole, enlarge enough due to a rapid escape of gas?

I almost forgot this.. maybe aluminum disk is too strong for a pneumatic device. Maybe plastic disk would be a better choice? Perhaps a disk made of brittle material which would shatter on impact?

[mark.f]

It most certainly could work. There have been a couple of people who have built these types of mechanically triggered burst disks. There was clide with his specialtee valve and sgort87 with his QCTBDC (links broken).

However, with the added complexity, why not just build a pneumatically triggered burst disk?

[Doctore]

It most certainly could work. There have been a couple of people who have built these types of mechanically triggered burst disks. There was clide with his specialtee valve and sgort87 with his QCTBDC (links broken).

However, with the added complexity, why not just build a pneumatically triggered burst disk?

You mean to simply overpressure it? Or to just use piston airgun and add bursting disks for faster gas release?

[mark.f]

A pneumatically triggered burst disk works by installing two disks inline with each other and filling the area between them with air at a percentage of the gun's operating pressure, then filling the chamber (behind these two disks).

When you vent the area between them, the pressure becomes enough to burst the first disk, which in short term bursts the second, making the disks pneumatically "triggered". Take a look at the page on the wiki.

EDIT: and of course some projects linked to from the page.

[D_Hall]

Another means of pneumatically triggering a dual burst disk design is to over pressurize the region between the two disks (rather than vent it). Functionally it's not that different but if you're fighting for every inch pound of energy it gives you a bit more since you're adding energy to the system to trigger rather than removing it.

[mark.f]

Another means of pneumatically triggering a dual burst disk design is to over pressurize the region between the two disks (rather than vent it). Functionally it's not that different but if you're fighting for every inch pound of energy it gives you a bit more since you're adding energy to the system to trigger rather than removing it.

Not to mention it takes a lot less air to raise the area between two burst disks a certain pressure than the entire chamber... especially something VERA sized.