SpudFiles

Using electricity through a solenoid or motor for full auto has been discussed before, but anyways here's my idea for it. It uses an air cylinder to cycle the breech rather than a blow forward bolt, because I wanted to minimize dead space between the valve and projectile, which decreases performance with a long projectile and low volume chamber that I would probably use.

The diagram should be self explanatory. The opening time should still be good even though the solenoid is opening the valve, because as soon as the pressurized air gets in front of the piston there will be a pressure differential pushing back on the piston. The only issues I see are building a circuit to control rof, the solenoid not being strong enough, and the ammo jamming or the breech timing being off, but that can be adjusted by the flow rate to the air cylinder.

Has anyone successfully built an auto electric yet? It seems there were a few ideas and plans but nothing ever panned out..

daccel wrote:Has anyone successfully built an auto electric yet? It seems there were a few ideas and plans but nothing ever panned out..

So it would seem, but no details of that mechanism appear to be available.

I had worked on a similar idea to yours in the days of spudtech and revisited the concept more recently.

Hadn't seen that spudtech one yet. Well I ordered a solenoid from mcmaster today, so hopefully the package forwarding works to get it across the border and I'll put a prototype together. Another thing I realized, I'm not sure I'll be able to get the o-rings to seal properly with only a drill for a lathe.

It was the difficult compromise between friction and sealing that put me off in the first place, good luck with that.

Hi,

I think I had the same first-hand experience as Jack there: It is difficult to get something to reliably drive 3 dynamic O-ring seals.

I have build several DFTVs - they have 2 seals that must be relly good, and 1 where small leaks are OK. The trick is to use a lossely fitting O-ring with almost no rubber compression in the latter case - and to find ways to keep the ring from blowing off completely. I guess you could try and do the same with the center one of your seals.

That cylinder driving the sliding breech - could you not hook up the left end of that to the chamber? Then it´s full pneumatic power in both directions; no springs.

PS: Try seeing if you could get anything useful out of splitting your big green piston into 2 (coaxial) parts: One is the exit disk part, and the other is the refill valve part. You might be able to eliminate the timing problem (get the exit disk to close before the refill opens).

PS2: Notice all that nice back pressure in your 2nd diagram? That will help the thing to open fast. Especially w/ a heavy projectile.

Regards
Soren