Pneumatic Internals for Artillery Pieces

[biged]

This started when I built this:


1.5" ASCO irrigation valve. Blowgun trigger. Chamber refills in under 2 seconds. Going to make it a breech loader. A very powerful 353 fps with a 56 gram tennis ball. Translates into 238 ft lbs of muzzle energy. It will break ribs under twenty feet.

Unfortunately this design does not resemble any ww2 piece. So after months of research I built a Linear Coaxial 2" piston, 1.5" orifice, 2.75" in diameter, 20 inches in length. I have not yet attached it to a barrel.



It works violently fantastic!! Releasing the entire volume of air in a millisecond. Almost as loud as a gunshot. (2x as loud as my mortar.)

You fill it from the rear (800 psi max - I have tested it up to 150 psi for now.). Close the ball valve. Disconnect the air. It's ready to fire. When you open the valve it dumps the volume out the front. A blow gun can be easily plumbed to act as a trigger instead of a ball valve. It can be fired about 15-20 times in a minute.

The piston can be easily removed to be serviced.

A picture of it before the outside shell was welded in place. The piston is the 1/4" rod with two seals, one in the front and one in the rear. The 2" pipe was cut to allow all the air to flow from inside the piston and the surrounding area to vent out the front.

A piston guide rail is added above one side of the cut 2" inch pipe before the outside shell is welded into place.


This one is going to be used in a M1a1 bazooka. But the idea is to create various sizes that are able to fit inside demilled artillery piece's to utilize the original barrel to launch "safe projectiles" for indirect fire. Barrel sleeves can also be added.

Drop-in internals for LAW's, RPG's, AT4's, Recoiless rifles, and yes Tanks. (Gordak had asked me once to make a pneumatic launcher for a towed recoilless rifle.)

"Safe projectiles" as in Nerf howlers, Tennis balls, or custom Pool-Noodle missiles.

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[YankeeDiv26]

As usual, you built another absolute lollipops ! Can't wait to see those in action sometime. Great work once again Biged.

[biged]

Completing the bazooka will take me about a month. I can only dedicate about an hour to it each day.
I'll post pictures when it is completed.

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[gryphon]

Wow! That is simply brilliant. With a simple mold and some two part closed-cell casting foam rubber, you could make full-scale foam "shells" to breechload into a field piece, slide your piston assembly in behind, fire, and reload using the same movements as a period artillery crew. (BTW, I have a mold for making full-scale foam bazooka heads, if you're interested.) I foresee big things for this system....

[biged]

Producing a dozen or so for a tank or artillery piece and using each one as a single round would be very realistic. Each one could be charged up and ready for use. Reloading each round with air and a projectile would probably take under a minute.

The longer the cylinder (or additional pressure) the more powerful the shot. I don't see any issues with running 800 psi. Which would up the FPS to 681 fps and 891 ft lbs of muzzle energy with a tennis ball. The barrel would have to be a optimized length with higher pressures.

Gryphon if you made a 150 gram "missile" at 800 psi that translates into only 540 fps with 1499 ft lbs(!) of muzzle energy but a range of 1000 feet easy. The numbers would go up as the barrel gets longer.

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[2nd Bat]

Yowzers! Very cool. I like the concept of two part loading. My 90 is designed with seperate rockets loaded from the rear which contain both the air power and the projectile itself. Hence it's a two man system. The loader pushes the shell into the breech and twists it so it's locked in place. I add Talc powder just behind the nerf rocket in the pre-loaded shells (for effect when firing)

They used to make a 2 inch nerf rocket that had noise enhancers attached to the foam nose cone. These Howeled as they flew through the air. As a result they announced their approach, making opposing players more likely to realize they were under attack and hence more likely to call themselves out. Our rules were the man closest to the impact was responsible for calling himself out if it was within 20 feet along with anyone else who might likewise be within a car length of the impact. If they had substantial cover between them and the impact they were safe. (Wall, big log, deep hole.) They are no longer produced but can be found on occassion. Whatever projectile you go with, if it's fired indirectly (God knows I hope so!) it should have some kind of noise "report" These howlers were very, very, cool.

With ranges like you're talking about a FO and FDC are quite feasible. The challenge of course is without visual impacts that can be seen by the FO it's real hard to adjust fire!

[biged]

The bazooka will be a breech loader. Breech opening hidden beneath the heat shield. A custom foam rocket could be inserted from the front. I still like tennis balls because they are cheap. But water balloons are also fun and because of their heavy weight will add 1/3 more range to the shot. I fill the balloons in the field with a pump sprayer. Put them in a Dixie cup then launch them.

More about making foam missiles:

www.argentlupus.com/CombatArrows.html
www.thesiegeshop.com/Pool_Noodle_Assm.html

Only one piston could be used in the case of a actual tank using one, the piston would be charged (takes 2-3 seconds, the bigger the piston the longer the fill time). A foam round could be inserted into the original tank barrel. Insert the piston and lock it in. You would have to come up with a way to lock it in place. Vent pilot volume and boom the foam projectile come out the barrel.
Making multiple pistons with rounds attached to the piston in each one is a daunting task. I would have to assembly-line a batch of them.

On occasion howlers can be bought in batches of 12 off ebay for about $50-$60. There is a paintball shop that makes nerf missiles. He makes Hollow-Point round so a paintball can be inserted into the end so the round can "Mark" it's hit when it lands.

www.bp-usa.com/FoamRocket.htm

I remember another discussion about how to make a "howler whistle" on one of the spud forums. I will have to look for it. My better half recently reminded to ask her father. He makes musical instruments (flutes, whistles, horns as a hobby) and to ask him.

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[2nd Bat]

The one piece foam rocket you show is awesome. The NERF ones when launched out of the high powered launchers you designed will often lose their fins during the launch phase where these probably would not. Great resource Big Ed. Keep us posted on your skunk works efforts.