Fabco-air Msv-2

[Walking Stick]

Hello,

I am planning on converting a mechanical marker (trigger trips sear to release hammer which contacts valve stem to open valve and release gas) to a pneumatic marker (trigger pushes MSV-2 lever to allow gas from PPS Rock regulator to extend cylinder to move a lever that depresses valve stem to open valve and release gas).

The PneuMags have the trigger returned to the set position via the sear, thus it also releases the MSV-2 lever. Since I do not have the trigger returned on this marker (as of yet , that is), the duration that the lever depresses the stem, I assume, would be allowing the gas to flow. So the longer I hold the trigger in, the longer the cylinder is extended and the longer the valve is held open. IS THIS CORRECT? Would this then cause velocity fluctuations and gas efficiency problems? This marker can then also be short-stroked (like Automags, Autocockers and Blazers)?

I just need to know the operation characteristics of the MSV-2. I thank you for your input.

[Pneumagger]

Say whazzuh???

Not sure if this anwers your question... but here goes.

everything happens at the sear. If the the sear rocks, the valve actuates. A mech mag has a trigger that manually rocks the sear. A pneumatic mag uses a piston impact to rock the sear - and the trigger controls the piston impact.

Mech mag = ~3lbs @ ~1/8" to move the sear <----Made of 1990
Pneumag = ~ 2oz @ ~1/32" to open MSV-2 flow <----Made of win

Picture the MSV-2 as an "on/off" type valve. It either lets air past or it doesn't. The air is at a pressure which allows the cylinder to move the sear reliably. Once valve the opens, the cylinder extends to max length very quickly because the high air pressure. There is no "in between" of the valve firing fully, half-arsed, or not.

Short stroking can happen if you attempt to cyle the marker too fast before the valve's dump chamber is filled - causing a weak shot.

-------------------------------------------------------

Short stroking a mag is not like short stroking a cocker. In a cocker you litterally short stroke the 3way valve travel, and a ball is reloaded before the original ball is fired - (to the best of my knowlege).
In a mag a short stroke comes from the valve cycling with a half filled "charge" of air - resulting in a weak shot that either plops out of the barrel or gets stuck.

Mags dont have hammers

Mags don't have stem valves

Mags use a predefined volume of regulated air to determine energy delivered to the ball - not a predetermined time flow (dwell) of a regulated gas.

Mags only reset (recharge) when the sear is released. Poppet guns continually recharge.


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[y0da900]

Yes, it would cause all of those problems. To alleviate, you would need to somehow control the amount of force the hammer hits the valve with, and the duration of which it hits. This can be done most easily in 2 ways. Make the hammer slide on the hammer shaft, as it reaches the end of it's throw, it slides forward and relies on it's momentum to fire the valve, and the valve closing will have enough force to push it away. Use a fixed volume pressure chamber prior to the switch so that it can only fire with a set amount of energy and doesn't continue to allow flow through as long as the trigger is pulled. There are other ways, but those are probably the most often discussed work arounds.

[Pneumagger]

wait, is he asking about making a cockerlike gun pneumatic?
Then yes, you'll either need dwell control via electronic valves or a fixed volume.

to utilize a fixed volume, try using a 4way valve (not a fabco MSV-2 3way) that passes air to a dump chamber, then when activated ehausts the dump to the piston, then when further activated exhausts the piston to atmospherw.. This assembly would only recharge when the trigger was forward.

[y0da900]

I thought that's what he was asking, but more like an open bolt electropneumatic, but using a mechanical valve instead of a solenoid valve and electronics. I could be completely off my rocker though.

[Walking Stick]

Okay, maybe this will paint a clearer picture:

1. I have a Model 98.
2. I want to convert it from mechanical to pneumatic (in the actuation of the CVX valve at least).
3. I will have a Palmer's Rock connected to the ASA.
4. The Rock will regulate flow to the MSV-2.
5. The MSV-2, when depressed, will release gas to a cylinder.
6. The said cylinder will extend and move a custom lever.
7. This custom lever in turn depresses the CVX (poppit) valve stem to release the gas in the valve that propels a paintball.

(Do not worry about the bolt, it will be closed and operated by a separate cylinder from a different gas line.)

My question:

If I hold the trigger down (a.k.a. keeping the MSV-2 depressed) for 5 seconds
Will the MSV-2 continue to let gas pass through it for that 5 seconds
Which keeps the cylinder extended for 5 seconds
Which keeps the custom lever depressing the valve stem (a.k.a. the main gas flow flowing into and out of the valve and chamber and barrel) for 5 seconds
?

OR

When I initially depress the MSV-2
Will it only let a certain amount of gas pass through
And then close automatically
Shutting off the flow of gas from the Rock to the cylinder
Ready to release the next flow of gas
For the next depression
?

Thank you if you are positive and able to help. (Yes, I could ask FABCO-AIR themselves, but I'd rather have first hand knowledge from those who have used the MSV for paintball specific operations.)

[y0da900]

Your question was clear enough, let me reiterate my answer, as it obviously wasn't.

Yes, it will continue to let flow through causing all of the problems initially listed.

To alleviate this, you need to either pick a different style of valve, and or, incorporate some form of mechanical dwell.

This can be done most easily in 2 ways. Make the hammer slide on the hammer shaft, as it reaches the end of it's throw, it slides forward and relies on it's momentum to fire the valve, and the valve closing will have enough force to push it away. Use a fixed volume pressure chamber prior to the switch so that it can only fire with a set amount of energy and doesn't continue to allow flow through as long as the trigger is pulled.

There are other ways, but would involve a lot more work.

[Walking Stick]

Much appreciated y0da900.

I was actually planning on using the Response Trigger system but with the Clippard MPA-3 actuator instead. The MSV-2 would be actuated at the top of the trigger and the MPA-3 would actuate/return the lower half of the trigger. I would just have to work out the timing and efficiency issues with this set-up.

I will look into fixed volume pressure chambers. I'll also go back and browse through product catalogs for FABCO-AIR, Clippard and SMC for any additional ideas.

If you have any suggestions or ideas (no matter the complexity) they are definitely welcomed.

[y0da900]

Much appreciated y0da900.

I was actually planning on using the Response Trigger system but with the Clippard MPA-3 actuator instead. The MSV-2 would be actuated at the top of the trigger and the MPA-3 would actuate/return the lower half of the trigger. I would just have to work out the timing and efficiency issues with this set-up.

I will look into fixed volume pressure chambers. I'll also go back and browse through product catalogs for FABCO-AIR, Clippard and SMC for any additional ideas.

If you have any suggestions or ideas (no matter the complexity) they are definitely welcomed.

That probably wouldn't work too well. The timing would be dependent on how hard you are pulling on the trigger as the force your finger is exerting will offset to an extent the force trying to push against the trigger, so the harder you pull, the longer it takes to reset, the longer the valve is open, the higher your velocity is, and the lower your efficiency is.

I don't think there are any off the shelf solutions for a fixed volume pulse chamber to control the dwell. They do make volumizing chambers that help to add dwell, but that is exactly the opposite of what you need. I'm not sure if there is a pneumatic circuit you could build with off the shelf parts either that would be able to fit inside a paintball gun, but it may be.

[y0da900]

Actually, Clippard does make a small pulse valve, but it fires in roughly 100 milisecond pulses, so it really isn't applicable. But they are out there at least.

[Nick E]

Actually....Just FYI, I threw this idea out there to some guys on PBN a while back, one of them did it, I think it was doyel..meh.

Anyway, the ram comes forward and snaps the valve open. Unless you have huge pressure ( and this is how you adjust your dwell/velocity) then it will pop open for a split second and then close, forcing the cylinder back a bit. This is how it fires.

[VVulfe]

I realize this is something of a necro-post, but the conversation here touches on a project I'm contemplating.

I've got very little pneumatic know-how myself, so please bear with me - where can I find, or read about how "fixed volume pressure chambers" work. In searching McMasterCarr and Clippard I can't find any mention of this part.

Thanks guys.

[Spider-TW]

I realize this is something of a necro-post, but the conversation here touches on a project I'm contemplating.

I've got very little pneumatic know-how myself, so please bear with me - where can I find, or read about how "fixed volume pressure chambers" work. In searching McMasterCarr and Clippard I can't find any mention of this part.

Thanks guys.

I think y0da was describing more of a designed delay, as opposed to an off the shelf device. You can see some interesting pneumatic devices in the fabco specialty catalog on the web. Notice the times are pretty much too long for our use.

A fixed volume pressure chamber (as a delay) is any space that you fill with an orifice (restriction) that will delay the buildup of the pressure you need to actuate the next part of your pneumatic circuit. Keeping the flow through (and pressure across) an orifice consistent to make a delay function on the order of 10 milliseconds is the trick.

[y0da900]

The part I reference is exactly the opposite of the Clippard PV-1 combined with a MAT-# in line volume chamber, you want to decrease the volume available to decrease the pulse time, the options from Clippard (MAT-#) extend the delay, making it even more useless.

[VVulfe]

I'm not doing anything revolutionary here - I've just had the goofy idea of trying to make a pnuematic sear tripper as an experiment in "I did it because I could".

The trick that this thread touched on, which I'm trying to find a solution to, is that in order for the sear to reset in the Tippmann I'm using, the actuator has to either retract - or move forward and then depressurize.

I want to avoid a situation where if the trigger isn't released quickly enough, the sear is held down, and the hammer continuously reciprocates.

Now, bearing in mind that I'm not hugely familiar with pneumatics, I have a few dim ideas of what could work:

1) A pressure chamber before the two-way. When the trigger actuates the two-way, the chamber dumps into the system, tripping the sear, however, because it's not continuous pressure, the sear spring is able to overcome the then depressurized actuator and reset. The immediate issue I see with this is a situation where - if for whatever reason - the trigger is simply held down, eventually the pressure chamber will recharge and the gun will fire without player intent. Or is that not how pressure chambers work?

2) Alternatively, is it possible to use a one-way valve that could be reset? IE: Trigger pull opens flow to the actuator for a preset volume/pressure/or time, and then trigger release resets this system?

Thoughts? Yes, I realize it's impractical, but I want to go a little Rube Goldberg on an old beater of mine.

(As a matter of forum etiquette - should I just take this into a new thread?)