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LAN_403

Ragnarok

Fri May 18 2007, 10:54AM

Registered Member #659 Joined: Fri Apr 20 2007, 09:14AM
Location: SW Hertfordshire, UK
Posts: 75

I don't know exactly how fast the round is going, but I can usually be sure to within a few m/s through a combination of different ways of getting rough measurements.

Steve Conner

Fri May 18 2007, 12:25PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Nice work, but if you're going to make claims like "Possibly one of the most powerful evur!!1!" I agree that they should be backed up with hard data, maybe from a chronograph or ballistic pendulum. Making a ballistic pendulum for a gun this powerful would be fun in its own right anyway. If you made one out of a watermelon, the result might not be accurate, but it sure would be entertaining!

BTW, I like the breech mechanism. Much better than boring old muzzle loading spudguns, even if it is a bit less versatile. I used to love shooting wads of wet toilet paper from my old air cannon, they made a hell of a smack and a huge splattery mess that stayed stuck to walls for days. Not sure how that would work with a breech loader.

The gun I used to have was similar, except it was made of PVC, had a commercial quick exhaust valve piloted by a solenoid valve, and was muzzle loading. And took about 5 minutes to charge with a footpump :(

Ragnarok

Fri May 18 2007, 01:01PM

Registered Member #659 Joined: Fri Apr 20 2007, 09:14AM
Location: SW Hertfordshire, UK
Posts: 75

The claim is only made about the valve. Based on the flow co-efficent of the valve (which is accurately known. Cv = 11.3), and a fairly exhaustive search showed are very few cannons of similar bore sizes that have used a valve of this flow - thus, the claim isn't actually that hyped-up.
The cannon itself has no 100% confirmed data, so I couldn't say (and thus I wouldn't claim) with any certainty that the launcher itself is the most powerful in it's size class.
Although, my previous launchers didn't recoil anything like as much as this one does - this kicks back firmly up to two inches with heavier ammuntion.

Actually, thanks for the ballistic pendulum idea - I'll experiment with making one to try and establish a confirmed power result. Unfortunately, maximum pressure is limited at the moment, as my track pump isn't working properly.
As for the melon idea, that could well be appearing on Youtube...

Coincidentally, I did fire wet toilet paper wads from my last cannon, at least until I made a mess of/through the garden fence with them by mistake. That wasn't easy to explain...

Bjørn

Fri May 18 2007, 01:41PM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

These are your claims so far:
High Efficency (absolute)
350 J (potentially)
Mach 0.9 (possible)

So naturally we are interested in seeing accurate measurements.

Ragnarok

Sat May 19 2007, 08:46PM

Registered Member #659 Joined: Fri Apr 20 2007, 09:14AM
Location: SW Hertfordshire, UK
Posts: 75

And I'll do my damnedest to get the evidence for them, as soon as I can sort out accurate velocity measurements.

In the meantime, here's some pictures of the new grip:

I spent a couple of hours creating the thing with my Dremel, making sure it was (almost) perfectly shaped for my hand. It is pretty comfortable, so that would seem to be time well spent.

The next thing I'll be trying to do is create a removable bipod out of M8 threaded rod. And after that, I think I've cracked a way of of rifling copper barrels successfully, but making them is probably a few months in the future.

AndrewM

Sat May 19 2007, 11:10PM

Registered Member #49 Joined: Thu Feb 09 2006, 04:05AM
Location: Bigass Pile of Penguins
Posts: 362

Heh, there went your plausible deniability...

"officer, this isn't a weapon, its research equipment!"

"unless you were researching the most comfortable way to hold copper pipes, you're coming down town."

Steve Conner

Sat May 19 2007, 11:36PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Yeah, if your claims are correct, that thing will be an illegal firearm in the Uk. I forget the exact muzzle energy limit but I'd bet you're about a factor of 100 over it.

Dr. Who

Sun May 20 2007, 02:51AM

Registered Member #326 Joined: Sat Mar 18 2006, 01:12PM
Location: Glasgow, Scotland
Posts: 66

Legal power limit for air guns in mainland Britain is 12 ft lb, or around 16 Joules. As your gun is smooth bored, and apparently exceeds this limit, you'll need to obtain a Shotgun Certificate in order to possess the gun legally.

In the current climate of media-induced gun hysteria and trigger-happy police, I feel it's very unwise to brandish any sort of gun-shaped object in your garden, especially when wearing camouflage clothing.

That is a pretty cool gun though.

Bjørn

Sun May 20 2007, 03:36AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

Thread the end of it and carry a tap that fits and you have Hertfordshires fastest tea dispenser. From zero to ceiling in one light squeeze of the trigger.

Steve Conner

Sun May 20 2007, 08:22AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

lol! ''It's a new kind of espresso maker, honest, Officer"

Thanks for the explanation of Uk gun law, Jim.

Also, sorry if my posts look slightly messed up, 1 am experimenting with handwriting recognition 8-/

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