HEAL 320psi 20mm copper cannon (now with damage videos)

Ragnarok · Posted: 11/01/2007 11:17 AM Post subject:

This is "H.E.A.L.", or usually, just HEAL without the periods.
HEAL is simply an acronym of the words "High Efficiency Air Launcher".

More specifically, it's HEAL v1.3, because it underwent a couple of minor rebuilds, then a pretty major one that changed a couple of things.
It cost me about £300, roughly $600 USD, through the various revisions, including the custom pump but to build it again from scratch would cost a bit less. A pretty large amount of money, but you get what you pay for - and, correspondingly, this is the single most powerful cannon I have ever built, out classing my old combustions in twice the bore size.

The design took into account most of the comments I had about my last cannon, Behemoth, making it both powerful, and reasonably good looking.

The length is about 29 cm longer than which ever barrel I am using, so for the current 125cm barrel, 154 cm. It weighs in at ~4.2 kg without attachments ,and increasingly more with attachments such as the suppressor, bipod and laser module. (Not shown in the pictures)

I can take it up to 22 bar (320 psi), but I usually use it at 10 or 15 bar. The valve is an optimised 22.1mm seat diameter piston valve with smooth flow edges to up the efficiency, piloted by a 1/2" QEV.

It has various barrels, two in 20.3mm bore, of 100cm and 125 cm, which have a basic sliding breech and a 26.3mm bore barrel in production, of currently undecided length - which will be muzzle loaded.
The chamber is 26.3mm ID by 120 cm in length.

I also have a few known muzzle energies and velocities for the 125 cm barrel. Typically, it will get about 400J at 300 psi, but with a heavier projectile, it will theoretically manage 580J.
I also managed to record an approximate muzzle velocity with a paintball, which clocked in at somewhere over 300 m/s (~1000 fps)

Some photos of it a little while ago. It has now got a bipod and muzzle twist lock, but I haven't got photos of that. (Also, I can't take them, as I don't have HEAL at the uni with me)

Full length picture
Rear
Valves at rear
Breech, handgrip and guard
Polymorph grip
Homemade high pressure pump

I'm afraid there are no videos, but I found this damage pic on my phone:
Frozen paintball through water filled box at 10 bar (there was a bin liner inside)
No doubt, I will get pointed at "The Box o' Truth" and asked how thick the box in question is. The box was 8 inches deep when the weight of the water forced the sides out slightly - and the paintball still exited the box doing a fair pace, making a mess of my backstop.

I know that I could punch tougher ammo through well over 12" of water, because my previous, less powerful cannon, Behemoth, could put a 3/4" steel ball bearing through 24 gauge steel, then 12" of water, then another layer of 24 gauge, then leave with enough velocity to make a hole through the 3/4" thick fence behind, and still leave into the fields beyond to never be seen again.
After that, I started using a backstop. (Normally a hefty chunk of tree stump that we have in the back garden from a tree the family had extracted several years back).

All the other photos are on the computer at home I'm afraid, and I'm not there until at the earliest the weekend after next, so there's a bit of a wait for more pics.

EDIT:
The video for your entertainment:

EDIT: Youtube vid down, you'll need Photobucket: Link to Photobucket mirror