HVPL-01:

 

Specifications:

- All copper construction

- Two 1" x 24" chambers (chamber volume: ~45 cubic inches)

- 1/2" x 60" barrel with muzzle break (barrel volume: ~12 cubic inches)

- 1" electronically activated solenoid

- Barrel sealing piston with spring return

- Cost: ~$54.00 (the solenoid valve and pressure gauge were purchased previously)

- Muzzle velocity: unknown (estimates around 550 f/s with a 15 gram projectile and 160 psig chamber pressure)

- Breech loading and detachable barrel

 

Planned modifications:

- Adding barrel supports to eliminate barrel movement and improve accuracy

- Lengthening the barrel so the projectiles will harness more of the available energy

- Burst disk experimentation

 

Performance and other Information:

I plan on using this launcher to accelerate projectiles that will be photographed impacting specific soft targets using stroboscopic photography. It seems to be a good candidate for the job because it is consistent, small, and is capable of very high muzzle velocities.

The first shots of this launcher with the weaker spring were impressive, but it really came to life after I upgraded to a heavy duty piston return spring. The one inch solenoid valve gives plenty of flow for the pilot chamber to be cleared quickly, which makes the piston's movement very rapid. The launcher doesn't fire well under 60 psig, which is fine with me.

A note of caution: Do not try and load tight sealing projectiles into a launcher when the chamber has even a small amount of pressure in it. While I was doing this I realized the trapped air behind the projectile could unseat the piston and cause the launcher to fire, but the ramrod only had two more inches to travel. I pushed it in another inch and then the launcher fired. The wooden ramrod slipped between my index and middle finger and shattered as it hit my fence, but the potato slug impacted my fingers. It was quite painful for a few minutes but nothing serious; it could have been though.

 

Photographs

Launcher and components:

 

[Rear view with trigger assembly, piston, and spring removed]

 

[An overview of the chambers with the trigger removed.]

 

[The 1/2 inch copper union breech upgrade.]

 

[The trigger assembly with a schrader valve, 0-400 psig pressure gauge, and a 1" solenoid valve.]

 

[This muzzle break was fabricated from a 1/2 inch copper tee.]

 

[The improved machine screw piston.]

 

[The old piston return spring, in its deformed state, after twenty shots.]

 

[The new piston return spring after more than twenty shots.]

 

[An overview of the whole launcher before the upgrades.]

 

Damage and Firing Shots:

* Photographs were taken before upgrades were added

 

 

[AAA battery after impact with a 1/4" thick steel plate (fired at 100 psig). One could say this Energizer battery didn't keep "going and going and going."]*

 

 

[A lead fishing sinker after striking 1/4" steel plate (fired at 110 psig). Notice the mushrooming.]*

 

[A barrel full of water was fired at 150 psig gives a nice fog effect.]*

 

[A 6 mm .20 gram plastic airsoft BB penetrated one side of this steel soup can at 150 psig from a range of three feet.]*

 

[The hole from an identical BB, as mentioned above, in the bottom of a soup can (fired at 160 psig at two feet) .]

 

[The entry hole of another .20 g airsoft BB in a steel can. This shot was at 160 psi and the impact point is the top corner of the triangle shape. The tearing of the metal was caused by plastic bag wadding as it entered the can.]

 

[This is the same can as above, but the opposite end. The BB had almost enough energy to penetrate both sides of the can.]

 

[Ten Pepsi cans await the arrival of a .20 gram airsoft BB with ~11 Joules of energy traveling at ~1100 f/s]

[This is the entry damage to the fourth can from the front. Notice the mouth flap has been pushed to the outside of the can.]

 

[The exit point on the second can. Notice any missing can material?]

 

[The BB as seen with the pieces of metal it removed as it exited four of the cans. It ended up passing through seven cans and becoming lodged in the eighth.]

 

Update: 05.08.04

[The mushroomed lead sinker seen in the foreground was identical to the one in th background before it hit a 1/4" steel plate. It was fired at 175 psig from a distance fo five feet.]

 

[Here is a differnt type of sinker, fired in the same manner as above, after impacting the steel plate. The sinker fragmented upon impact and ejected the semicircular fragments up to seven feet from the impact area.]

 

[This sinker was fired at a .5 mm steel sheet at 160 psig. This caused a large dent in the sheet, but no penetration.]

 

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