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Shooting the Trom-Boyn

Built a pneumatic cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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Shooting the Trom-Boyn

Unread postAuthor: boyntonstu » Wed Dec 23, 2009 11:42 am

[youtube]http://www.youtube.com/watch?v=kNrLawUmDFo[/youtube]

200 psi pressurized in the chamber prior to inserting the barrel.

Note the new nail dart design.

Not only is it stronger, but it makes 2 seals and keeps the nail centered in the barrel.

Smooth as silk trigger.

The new dart should go to at least 300 psi.

My goal is 550 psi
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Unread postAuthor: elitesniper » Wed Dec 23, 2009 11:48 am

cool breech system!
nice gun too
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Unread postAuthor: MountainousDew » Wed Dec 23, 2009 2:18 pm

Aren't you going to answer the phone?
It could be important! haha.
Nice gun and dart design.
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Unread postAuthor: McCoytheGreater » Wed Dec 23, 2009 2:30 pm

Aren't you going to answer the phone?


hahahaha! I was thinking the same thing.

How do you keep the gun from popping apart without the pipes being soldered together? Am I missing something? It does work. And that's cool.
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Unread postAuthor: boyntonstu » Wed Dec 23, 2009 3:32 pm

McCoytheGreater wrote:
Aren't you going to answer the phone?


hahahaha! I was thinking the same thing.

How do you keep the gun from popping apart without the pipes being soldered together? Am I missing something? It does work. And that's cool.



I have shot it at 300 psi and the 0.6" fitting insertion depth plus the dual T's have enough friction to hold the barrel in place.

Surprising.

What it means is that you can do away with a bolt if you design your gun along these lines.

Another possibility is to 'play' the Trom-Boyn as you shoot, placing back force on the barrel.

So far unnecessary.

Darts are easily loaded and it shoots very well.

One additional benefit to the slide load is that you can look down the barrel to check for fouling.

My sequence is:

Slide open the barrel from the T to the side.

Inspect the barrel.

Load a dart.

Pressurize the chamber.

Insert the barrel.

Shoot.

A bonus of the slip T design is that barrel can be removed and the 'plumbing supplies' can be carried in 2 pieces.

It was a pleasant surprise to learn that soldering the barrel to the T was not necessary (so far).
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Unread postAuthor: pizlo » Wed Dec 23, 2009 4:34 pm

Hey, this is like the 4th topic from start to finish of this gun... most people are content with one. Looking at how you put

extra

lines

in your posts it's apparent you like to stretch things out. But nice gun, its clean, works well, and seems a bit unique, have you thought of working out a rifling system for your guns?
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Unread postAuthor: boyntonstu » Wed Dec 23, 2009 4:52 pm

pizlo wrote:Hey, this is like the 4th topic from start to finish of this gun... most people are content with one. Looking at how you put

extra

lines

in your posts it's apparent you like to stretch things out. But nice gun, its clean, works well, and seems a bit unique, have you thought of working out a rifling system for your guns?




Have you ever seen another side swinging breech loader?

I prefer smooth bore and a rotating dart.

From Wiki:

The cannon, in the form of the tank gun, has made the transition from smoothbore to rifled and is moving back to smoothbore. To reliably penetrate the thick armor of modern armored vehicles, a very long, thin kinetic-energy projectile is required. The longer the projectile is in relation to its diameter, the higher the spin rate must be to provide stability. Practical rifling can only stabilize projectiles of a limited length-to-diameter ratio, and these modern rounds are just too long. These rounds are instead formed into a dart shape, using fins for stabilization (see kinetic energy penetrator for information on how this works). With the fins for stability, rifling is no longer needed and in fact the spin imparted by rifling would degrade the accuracy of a finned projectile. The first tank with a smoothbore gun was the Soviet T-62, introduced into service in 1961, and today all main battle tanks except for the British Challenger 2 & Indian Arjun MBT support smoothbores.

This was my first post in the showcase thread.
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Unread postAuthor: boyntonstu » Mon Dec 28, 2009 10:44 am

The latest news is that I was able to shoot a dart at 400 psi, BUT, the barrel slipped out a bit.

Solution, a Velcro 'bolt' mechanism.

I hot glued a strip of Velcro a turn around the piston T and I wrap it around the movable T soldered to the barrel.

Pull tight and the Velcro hold it in.

Fast, and simple 'bolt action'.

My challenge it to design nail darts that will be reliable at 400 psi.

I am batting about .250 but I am learning as I go.

One concept is to increase the tail length by inserting cones into the first one on the nail.

Having a longer tail about an inch places the cg forward and stabilizes the dart.

In addition, 2 or 3 cones make contact with the barrel.

YMMV
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Unread postAuthor: Brian the brain » Mon Dec 28, 2009 5:24 pm

Caulk tips with nails glued in 'em work great for me.Very sturdy and they fly very straight.

If the muzzle blast is to blame for instability, a muzzlebrake should do the trick.
Just drill plenty of holes in the last section of the barrel so the air can escape without making he projectile tumble..sand it afterwards ofcourse..
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Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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