I'd like to present my latest project. It's airsoft V2 gearbox modification to gas system version.
The greatest advantage is regulated ROF and FPS.
On my Website are free project files to download - 3D model designed in Solidworks.
Take a look at the promo-video and some pictures below:
Interesting. If I understood correctly, the spring piston is replaced by a blow-forward bolt, which is fed with pulse air from a solenoid valve controlled by that magic box to vary rate of opening and opening time.
Some questions:
- what sort of fps and rof are you getting?
- is the added bulk of the valve system, power supply and gas supply worth the power ?
- do you plan on having everything gun mounted, or in some sort of backpapck?
hectmarr wrote:You have to make many weapons, because this field is long and short life
Electronic unit controls the solenoid. Using two potentiometers you can control solenoid (opening, closing times) I used a NE555 timer. Solenoid and electronics are powered by 12V battery.
Air pressure from solenoid goes to cylinder and moves the piston and after a while shoots BB Pressure drops, and piston goes back to start position. System is ready to next shot.
Rof is regulated -> typically 3-20 RPS. 20 BB/sec are possible with low pressure 7-8BAR. With high pressure (14BAR) I get 15-17BB/sec.
Personally I'll put this to backpack. But if you want you can use a full stock of gun.
FPS are pressure-dependent and dependent of barrel length. I get about 480FPS with 40cm barrel long.
I think it is worth to use it, becouse in very simple way you can adjust FPS, ROF and you can eliminate typical high-speed motor sound.
Yes, 3/2 type solenoid has a venting output, and 2/2 valve would make cycle too slow. I used 2/2 type solenoid in my first version - video is on YouTube. As you can see it's too slow.
Yes, it would be amazing, but it's almost impossible. Mini solenoid has too small air-flow.
Second piston o-ring is needed to stabilize piston in the cylinder.
I like the idea of using an existing airsoft shell, however having to carry an air supply and electronics seems a little too bulky - have you thought of replacing the solenoid using a pop-off valve directly or pop-off piloted exhaust valve in order to pulse the air to the bolt? It could also be mechanically adjusted for power and ROF by altering pop-off pressure and valve flow respectively.
With some effort you could make the bolt itself the valve:
hectmarr wrote:You have to make many weapons, because this field is long and short life
The mechanical unbalanced spool valves are basicaly JSR's drawing with a sear. The sear could be controlled by a solenoid for ROF.
Does FPS have to be controllable on the fly ? If not the feed pressure could be set on the regulator. Often how its done on paintball guns, even electro-pneumatic ones.
Although FPS could also be controlled by a solenoid on the fill side, controlling the little pin, at a set feed pressure, more time open=higher chamber pressure.
The electro-pneumatic versions obviously allow more control offer the firing and even though they still require a 3/2 solenoid valve, would require a much smaller one, as it is not the main valve.
Pressure drops, and piston goes back to start position. System is ready to next shot. 
