TKLabs Replication: Coolnvention’s Co-Axial Pneumatic Flashlight Projectile Launcher

WARNING: Don’t try this without safety glasses, and DON’T EVEN THINK about shooting at a person or animal with this thing. And especially don’t take it to school, fool.

Erratum: In the video call the original maker “Cool Inventor” but it’s Coolnventions or sagar96. Sorry for the confusion….

Yes, it works. It’s counterintuitive, so people are calling it a fake or hoax, but it’s not.

Once you understand how it works it makes perfect sense, and then of course actually to build one and fire it removes all doubt.

To see the animation that describes how the piston manages to allow the air to push the projectile, please see the instructable by sagar96 that is cited in the video.

http://www.instructables.com/id/Co-Axial-Pneumatic-BB-Gun/?ALLSTEPS

Basically, the piston divides the flashlight into two chambers, the front one on the barrel side of the piston, and the rear one on the valve side.

When you pump up the thing, the piston gets pushed forward and seals the barrel, but air leaks past and pressurises the forward chamber too, so the whole flashlight is pressurised and the piston is held hard against the barrel, sealing it tight, and the pressures in the two chambers are equal and balanced.

When the valve pin is pushed, the air in the rear chamber rushes out the valve. This allows the air in the front chamber to push the piston rearward, off the end of the barrel.

This lets the pressure in the front chamber rush out the barrel, pushing the projectile out the muzzle at high speed.

I modified the original design by using a synthetic wine cork instead of the epoxy plug shown in the instructable, and I found that the door stop tip was perfect as a piston, and I only sanded it a tiny bit to smooth the edge for a good fit.

I removed too much material on the first one and this let all the air rush out the valve so it didn’t work. But there were four tips in the package, so I made another one, with a good tight fit, lubricated with vaseline, and it worked the first time I tried it, scared me and the dog silly. And it’s worked every time since, too.

Please go to sagar96’s instructable and give him positive comments.

http://www.instructables.com/id/Co-Axial-Pneumatic-BB-Gun/?ALLSTEPS

Materials:
Brinkmann 2AA-cell flashlight (MagLite clone)
car tire valve stem stripped of all rubber
new valve core
synthetic wine bottle cork
6mm ID acrylic plastic tube
8 mm – 5/16″ door stop tips
5-minute epoxy
superglue
vaseline
6mm airsoft ammo

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