The OT thread V1

[pbjosh]

the firing valves function is the determining issue, not simply the angle of the seal

Which was most of my point for the last couple of pages and years.

[cockerpunk]

https://www.youtube.com/watch?v=po5VUW3I8P8

stability lobe diagrams, learn em, love em

[Menace]

John,

Thanks for the lay-termed explanation, together with pics and descriptions.

Can you help clarify some things?

The bolt stem has one diameter and hence, one land (to use the terms given), and no valleys, unless you think of the end of the stem as a kind of valley. So it looks nothing like the examples given in post #2408.

Moreover, it doesn't actually stay in the valve body/bore like a normal spool does. Rather, it jumps completely out of the sealed area/bore every time it shoots, rather like a cork gun, and the brass power tube tip helps keep it from falling completely off, and the spring serves to reel it back together and prevent it from flying downrange.

The power tube o-ring takes massive abuse as a result of this, and is the most failure-prone part of the marker.

That just doesn't sound like a normal spool, all of which seem to stay sealed up in the valve body in some respect during operation. That sounds more like what happens when a poppet is knocked open.

I can imagine someone marketing this as a pressure-actuated poppet, knocked open by force of dump chamber pressure on the rear face of the stem (which is what actually happens). The sear simply prevents it from being continually knocked open. If you were to remove the sear and open the on/off, it would go full-auto, much as you would get with a poppet experiencing hammer bounce.

Don't know if that changes anything or not, but again, that doesn't seem to be what a spool would behave like.

On the other hand, if that is all that is needed to make a spool, then I suppose that's that.


At any rate, thank you for entertaining this sidebar, even though it isn't your cup of tea.

[ironyusa]

It is still a spool. The low lift characteristics of the valve are still influenced by the overlap in the lands even if the port is coaxially positioned. Seeing an exhaust port in this arrangement is quite common on pneumatic spool valves and that's exacly what this is... You'll seldom see it on hydraulic applications because you don't really want to discharge fluid.

[going_home]

What would this one be ?

https://www.indiegogo.com/projects/r...-game-sports#/

[ironyusa]

I can tell you what it's not... A "recoilless paintball marker." It lacks the ability to counteract the force from the ball.

I think it's likely a goofy arrangement of a rotary valve. I'd assume it's 1 complete revolution per cycle and to get a reasonable cycle rate is going to require a good amount of torque which will add twist to the feedback. Cool attempt at innovation though.

[Simon]

Ahh rotary breeches... not a fan of that concept personally.

When we made the E-Volt the torque of the motor made the gun move very strangely in your hands. Kind of like using a hand drill where the bit suddenly got stuck. It wasn't horrific when shouldered but it wasn't a pleasant sensation.

[cockerpunk]

when shooting the FN303 with the accelerometer to measure kick, we could see the magazine rotation in the data trace.

really kinda interesting.

[ironyusa]

That's a canister type magazine, right?

[cockerpunk]

That's a canister type magazine, right?

more like a drum.