autococker valve/other valve: time it needs to stay open to fire/changes

[QUINCYMASSGUY]

OK, got a question about valves,springs,and the air pressure pushing on them.

For this demo lets go with an autococker valve. How hard would the hammer have to hit it to open it enough to effectively let the air go to the ball and fire it consistently and how does it work that the valve stays open until it has fired with the spring acting against it to push it back. I take it it wouldn't close until the hammer is pulled back? What would happen if a shorter valve stroke was set up and how short/light hammer stroke can be used to shoot consistently?

What the root of my question is, is how does this type of valve system work to efficiently and consistently shoot the paintball at a 30bps rate? Or 20bps?

[the electrician]

well that's alot of stuff. I don't know about all of it, but I'm working on a project that started with some tests on an autococker valve. I used a ram to open the valve from a dead stop. in other words, no stroke length before it makes contact with the valve stem. it is sitting right against it. I noticed with my paticular valve spring and the input psi at 200, that it took 25 lbs of force to open the valve to succesfully shoot a ball at a average velocity. this was calculated by taking the input psi of the ram and the multiplying it by the force factor of the ram(air cylinder). the valve was being opened about 3/16". which is about as far as it can, being the stock valve.

this of course, is not efficient at all. it wastes alot of air. the test was only one of many to figure out some optimum design configurations. the latest design uses no hammer, no hammer spring and no valve spring. instead it's a valve in the center of a ram so to speak. this seems to be much more efficient and much more responsive. I still have to do some air consumption tests though.

so maybe that's one answer.

[QUINCYMASSGUY]

distance

With such a short distance, could maybe a lighter spring be used to re-seal the valve, in other words push against the direction of the ram? Or would issues arise from this?

[AzrealDarkmoonZ]

I will try to answer your question as simply and generalized as I can...it depends...

We are going to assume the hammer can be represented by a pounds of force, ie the mass and the velocity of the hammer going forward. Now counteracting this is the valve weight, and the pressure behind the valve and maybe the spring.

The valve is a properly tuned cocker will only open for a fraction of a second after the hammer hits it. It is the hammer that hits it and then bounces back and no longer as the strength to exert any meaningful pressure upon the valve stem.

To get the root of your system is essentially boils down to a few very basic premises, the most basic and single word answer is "dwell" @ 300 FPS or how long that valve is open.

The other two are of course forces acting to open the valve, hammer + attached items wieght + spring power. And of course the valve weight, pressure and maybe the spring.

The poppet valve is a VERY very fast system, I believe Tom even commented that the valve itself is much faster than the entirety of the RT.

To get your BPS, exempting any other restrictions, getting the Dwell down is key to efficiency and cps.

Also you may want to refer to my study Pressure and FPS, a few posts below this one, and Azreal's Guide to Cocker @ www.air-powered.com under articles.

Az

Az

[the electrician]

yes you can use a lighter spring, but what is going to happen? the valve will open a bit easier, but what is really holding the valve closed at that point? the input psi. the 200 psi behind the seal has much more force than the spring does, so you don't gain. this lighter spring will make the valve close slower and waste air long after the ball is gone. this lighter spring idea is why alot(not all) of cockers set-up to run on "low pressure" are actually wasting alot of air. which can be extremely detrimental to high bps.

I'm heading in the direction of removing springs altogether, along with the hammer.it's strange. when I dry fire it, it sounds like it is not expelling enough air to shoot a ball with any speed, but when I shoot a ball, it chronos at 290. so I'm getting closer to what I'm looking for. it will end up being a different gun altogether, not a modified cocker.

[AzrealDarkmoonZ]

Elect, how are you going to counteract the force behind the cup seal, ie surface area + psi? and still retain the poppet valve like structure?

Az

[QUINCYMASSGUY]

pressure

Well what about if the top of the valve had a thinner head, much like the mag on/off or, better yet, the ult on/off is designed to reduce the surface area so it doesn't take as much to push it open.

[the electrician]

well what I described earlier was only a test. trying to open the poppet from a stand still opens it too slow. I just wanted to get some force measurements.

the design is a simple copy of a piloted valve. I noticed that larger solenoid valves that were piloted, were actually piloted by a smaller solenoid valve that controlled air flow to two side of a valve stem. this gave it plenty of power to open and close quickly, without using a larger solenoid and more wattage. I couldn't find a valve with the right air flow, even though I found several poppet style, piloted valves. so I just apply the design to the exesting cocker valve. the test rig is now a very crude set-up, but effective none the less.

basically the gun can run on 200 psi, have an input to the valve control of 50 psi, a solenoid energize time of 5 msec(that's pretty damn low) and open the valve 3/16". it will shoot a ball at 300 fps. now I need to do some air consumption tests to see if it's feasible, and also some bps tests to see where it tops out and why.

I noticed that if I open the valve more than 3/16" , it didn't help, but if you open it much less, it lost velocity(the ball did). if I increased the open time by increasing the energize time of the solenoid valve that controlled it, it didn't help the velocity either. but any shorter and it lost velocity, unless higher psi was given to the control valve. which to me seemed to not be worth gaining one extra msec. too much air wasted for the gain.

now of course I know these specific measurements apply to my specific set-up, but I think it gives a good idea of what you can expect from most cockers.

Az, I don't think I understand you're question. I'm a bit slow some times.

[QUINCYMASSGUY]

Az

I think what Azrael was asking was how are you going to counteract the air pressure applied against the top of the valve head which contributes more resistance for the hammer to act against and what I was getting at was can we decrease this amount of pressure being applied to the top of the valve head by decreasing the surface area, in other words making the valve head no wider than the valve stem and seal it with an oring, much like the Automag on/off. So.......

Mandatory Force of Hammer At Point Of Impact=MF
Pressure resistance against the valve head=V
Spring resistance needed for proper valve function=S
Distance cocker valve pin must move to effectively allow air for 300fps=D=3/16inch
Time valve needs to stay open=T

So to open the 3/16" at all
M=D*(V+S)
To open the 3/16 and also keep it open long enough to fire. Note air pressure is factored out for the additional required force as once it has open and the air is flowing, the pressure in front and behind the valve pin/head is equal.
M=(D*(V+S))+(T*S)

Now think about this: the function of the hammer/valve setup is VERY similar to that of the full function of a Mag. Sear is moved, prestored pressure released (spring for cocker, air for mag), has to act against a force (air for cocker, spring for mag), and move a particular distance against that force. So the idea is we need to find the lightest pressure possible to consistently let a valve head open and some options for doing this are:

To lighten the spring used to reset the valve pin
Pros: Slight amount less pressure needed by ram
Cons: Slows reset time. Shouldn't decrease below 30 full cycles/second.

Drop the spring force that pushes the ram
Pros: Less force needed to reset the ram
Cons: Lowers ram speed and force

Decrease surface area of valve pin
Pros: Much less resistance against valve pin
Cons: ?????????

By lightening the spring needed to fire the ram, and maybe keeping cycle rate up by shortening it to just maybe 1/4 inch from the valve, the pressure required could be dropped enough to pinch paint. But back to the original question: how much force is enough to open it enough (3/16?) and keep it open long enough? I just looked at the cocker valve and realized that when it fires, the valve will stay open until the ram moves back again so that kills that question, but I guess I should rephrase to question to be: to acheive 30cps at any firing pressure, how far should the valve pin open? Would it require the same time for Low Pressure and High Pressure systems?

EDIT: Just FYI, I set the figure at 30cps as, although no one can shoot that fast, it is important to have a marker be able to achieve any humanly possible speed with room to spare. 20-25cps would be fine too.

[the electrician]

Hmm.

first off, in a cocker, the hammer only moves about a 1/2".
about 5/16" before it hits the valve stem and the other 3/16" to open the valve. it should open this amount. opening the stock valve more than this, showed no gain. now how long it has to be open, I'm guessin' 3 msec.

this guess is based on the lowest solenoid valve energize time I can use for my particular set up(using a ram to open the valve with no hammer)is 5 msec. I'm guessing the reaction time of the MAC valve I'm using, to be around 2 msec when being fed 9 volts.
now I don't know for sure, but I imagine that at higher input psi to the main valve, the valve may not have to be open for as long. and at lower psi, it might have to be open longer. but for what I did, I noticed my gun couldn't get the ball to go 280 fps with an input lower than 200 psi no matter how long the main valve was open. so I figure 200 psi to be a sort of minimum input pressure for this set up.

so my opinion is that shortening the hammer stroke length before it hits the valve stem would not help, maybe perhaps reducing hammer weight would gain speed if that's what you're looking for. but I'm not sure what that would do in a standard cocker set-up. you might need too much added spring tension to make up for lost weight. I'm not sure. I know that I am not using a hammer at all with the ram set up I'm experimenting with. and I noticed that using a hammer didn't really help all that much, and actually slowed the ram down some.

reducing the surface area of the valve seal might make it easier to open, but of course, less area means less flow of air. at some point flow will be lost and velocity will be too. at that point the only other thing that would get it back is more input pressure. so I guess it comes down to this:how small can you make the seal dia. and not restrict flow any noticeable amount? older valves have a smaller hole and therefore smaller seal dia. this might be something to experiment with. but then wht do the AKA tornado valves work well? they have about the largest seal dia. I don't know.

if you lighten the valve spring, you miss the cons of that. it causes hammer bounce to have too light of a valve spring. this along with the slower valve close time wastes air, and can posibbly cause blow back.

lightening the hammer spring is something that most cocker owners do. cockers can easily be set up to pinch paint. that's a whole other subject.

I still don't understand Az's question. a ram opens the valve. it has a bit of stroke length before it hits the valve stem (about the same as a standard cocker). for some reason it works well with no hammer, and a hammer doesn't cause it to gain energy through momentum of mass, therefore it doesn't seem to help. I don't really know why right now. when the solenoidvalve that controls it is de-energized, the air goes back to the other side of the ram(and valve) which closes the valve. this way the "dwell" of the valve can actually be set to a specific amount of time.

I've got it down to 50 psi input for the ram. being a 1/2" bore cylinder, that means it's only generating 9.5 in/lbs of force.( 50x.19=9.5 ) big difference from the 25 lbs needed to open the valve from a stand still! I think it has something to do with the speed and power it gains for the 5/16" of stroke before it hits the valve stem. I tried lengthening this, but it needed a lot more energize time and didn't seem to help.

[QUINCYMASSGUY]

fun

This is fun, lol

OK, so the hammer moves 3/16" to actually open the valve, I wonder if that 5/16" could be shortened at all without increasing the force needed at all or just a little without greatly increasing the trigger pull weight needed?... I have an idea I'm working on with this that would need it down to 4/16".

I wonder if this 200psi can be dropped, do you use a mitey max or LP chamber? This would be efficiency related but lower pressure = less force needed against valve to open it. Not a huge deal if this can't go much further down. How do vikings and trixes shoot so LP? Not cycle, shoot is the question.

Working on some other thoughts, to be continued...

[the electrician]

this is fun. watch a little football, talk a little paintball.

okay, so you want "momentum stroke" (for lack of a better term) to be shorter? and the purpose? like I said, when I reduced the this part of the stroke the extra force needed went up exponentially. from 9.5 lbs. all the way to 25 opening it from a stand still. so I gave up making it shorter. opening a poppet valve without some "momentum stroke" is very inefficient and the optimum momentum stroke seems to be exactly what the stock cocker has. but you could make it a 1/4" and probably not suffer to much. it's all give and take. just how much do you want to give for what you want to take is always the question. some people confuse this with performance gain with alot of things they do to cockers. only things that increase efficiency, in one way or another, are truly performance gains. such as using QEVs on a ram. but I won't get into that. it's off topic.

200 psi is about as low as I could get my particular test set-up. AKA does amazing things with low psi and efficiency. I'm kind of intersted to see what a tornado valve's minimum psi input would be in this set-up. but not interested enough to spend the money. 180 is not that much lower than 200. I'm thinking about trying this turtle valve made by bob long. it's got a better price and an interesting design. allegedly, it opens easier than the stock valve and most valves, due to it's design. I don't think a low psi chamber will do anything at all. it's not starving for air.

I tell ya, the more I learn, the more I realize how little I know. the further I go, the more respect I have for those who have designed these incredibly reliable and consistent paintball guns. agd, wgp, palmer, AKA, even the matrix and intimidator. they are the ones who have provided the foundation.they really are impressive designs compared to any feild of innovation.

the questions you have to ask yourself is this: what am i tring to accomplish? and is it worth what I would have to do? is it realistically feasible?

[QUINCYMASSGUY]

start

It really has been a combination of innovation and trial and error. They are smart people though. But remember, we are working on someone else's train of thought. We may miss things they saw, but see things they didn't.

OK, so a shorter stroke is possibly, cool. And 25psi to push the ram enough to cycle effectively is pretty high, how many cps you think you're getting with that? So if I cut the distance in half it would be around 15-20lbs? And a better question is how fast do you think a cocker valve needs to be opened to efectively shoot? Like, if it went slightly slower would it screw up the shot? By slower I mean still within the time it takes before the three way to kick in and move the bolt back.

And what was the way you were thinking for cockers to not chop paint? One way is lowering the LPR but how low does it need to go to pinch?

[the electrician]

I don't know. I imagine the force needed to open the valve would still be high. your guess is probably close.

as far as how fast the valve should be opened, as fast as posibble. a miniimum speed I don't know. I do know that it only takes about 3 msec for the ball to be up to speed. any air being expelled from the valve after that is wasted and can cause blowback. so no matter what you do, the faster you get the valve open fully, the better off you are. and then get it closed as soon as you can.

I've noticed that it is really hard to chop paint if the cocking force is 3lbs. you literally have to hit the ball with the bolt 6 or 7 times to get it to break at that low force. now at 5 lbs, it's definitely possible, but most paint can take a hit or two at that force.
so basically a stock ram is 3/8" bore, and has a force factor of .11so multiply that by the input psi, and there you go.
the best way to get low cocking force and keep up the speed is to use lighter springs, a light, low friction bolt(delrin), and definitely QEVs on the ram. then you can go further and drastically reduce you cocking mass and use a low friction ram.

I use an ANS mini, a delrin bolt, delrin back block, delrin pull pin, aluminum pump arm and most importantly, QEVs. this let's me run a low cocking psi, without losing speed.
I can run it at 40 psi and still get 15 bps with the halo. that means I don't need an ACE.

after doing these mods, the key to using it at it's potential is to feed test the set-up, and set the rof to the feed rate. then you will not chop or even worry about pinching. it makes the gun extremely reliable. I haven't chopped paint in the breech since I did it to my old electro cocker. I did the same to my friends electro-cocker and it hasn't chopped since. that goes for all guns.

[QUINCYMASSGUY]

pinch

I'll have to read this again tomorrow, I just got in and my brain isn't firing on all cylinders right now. The part about the valve opening enough to let all air out before the 3ms mark makes sense, I just have no clue how to figure THAT out, lol

Could you elaborate a little more on the force factor? Not sure how you got that number or what it is. And sorry for being an idiot, but what are QEVs?

So that means your bolt pressure is .11X40psi=4.4lbs??

More thoughts tomorrow...