How many times can an autococker cycle per second?

[FooTemps]

Originally posted by Paladin


With paint being force fed into the gun by air flow and mechanical operation of the trigger with a vaiable speed drill I can easily get "shooting" speeds of up to 20 balls per second with my auto-cocking guns and do it without any "shoot down" at all if there is adequte air supply to the gun at 500 - 600 psi.
Actual cycling speed potential is beyond what I have the means to measure accurately. I haven't yet found the point at which the valve "floats". Like out-reving the valve train on a car motor. If your typical automobile engine can rev to say 5000 rpm safely a paintgun should be able to easily do half of that; so 2500 RPM works out to 41.666 blasts of air per second.

Cool, can you test any other types of markers in the same way?

[Paladin]

Speed testing

Originally posted by FooTemps


Cool, can you test any other types of markers in the same way?

Well, just about anything with a trigger could be tested like that but the rig I made up was a temporary thing and ruined a grip frame to do the test.

The feeder was just a piece of PVC with air hose hooked to the top of it and vented at the bottom. All K.I.S.S priciple stuff. Not at all like the fancy rig that Tom set up.

[pbjosh]

Hello!

I have a couple of Raceguns laying around, and figured I will drop numbers for all of you to work on. If you have any questions I hope I can gather them for you.

I don't know if you have seen the Racegun R.I.P. software, but it allows a you to time 5 points on the firing cycle of the gun. Shot, Dwell, Open, Load, Close. Broken down, and timing related to them (please excuse, it is about 1 or so here and I have been putting in 14+ hour days on the computer and such):

Shot is the timing for the solenoid in the grip to release the hammer. This can be set down to 5 ms in the RIP program but with earlier software this can be set to less. With a bit of setting It can run at 4 ms or less. This is only for releasing the sear.

Dwell it the between the Grip Solenoid turn off point and the time the second solenoid is opened. This is where a person can tune out blow-back and tune in ball suck, something I really didn't believe in until I did it. To time in 'Ball Suck' or time out blow back a person needs to have about 13-18 ms total cumulative time with the Shot and the Dwell settings. I have found that most LP cockers, short of a well tuned AKA, have very long dwell time. Blow back is still felt at 15 ms total Shot/Dwell timing. This can add alot to the total time on the 'Cocker. If a person has a fast asking valve, with a healthy valve spring or a large cup seal, they can lower the total Shot/dwell to about 10 ms. That is total for the Hammer to release from teh sear, the hammer to move forward, hit the valve, and the valve to close again, and then the time for 'Ball Suck' affects to happen.

Open is the time it takes for the Ram to push all the bolt/backblock/cocking rod and such back to re-engage the sear. This is based on a bunch of fun stuff, but for the most part the largest restricting factor is the spring tension on the hammer. If the hammer spring is set really heavy this will slow the action down considerably. And a heavy hammer and/or spring will lengthen the valve dwell time. Open on a fast cocker can be under 18 ms. Most run about 20 ms or more. If a person wants to lower this time they can apply more pressure to the ram or get lighter components. For timing load and figuring out the length of the setting I am going to copy the 'Matt' method off of Raceguns site:

"How do I find the optimum (shortest) Open and Close times for my setup?
Answer: This expert advice from Mats Olsson, our Swedish Cocker guru:

To find the right Open and Close times for your Racegrip and Cocker, go through these steps:

1/ Set to Semi mode
2/ Set (or leave) your LPR to the right cocking pressure.
3/ Set Load to 1mS
4/ Increase Open step by step from 10mS until the lug stops riding along and actually catches the sear (single shot, pause, single shot etc).

You now have the minimum Open time set.

5/ Add a few mS to be on the safe side.
6/ Set Close to 2-3 mS lower than Open. You can experiment with lower Close times later on, too low will cause blow back.
7/ Set Load to 35mS and work down until you start chopping (or feel happy with your BPS).

You probably end up with something like 8,8,30,35,27 or so with a 12v revvy."

Load is the time it takes to feed the gun. Simply put, load is the time the bolt is truly open. Load and Open are really one action on the Solenoidvalve on the front bracket of the Racegun Setup. Total they cover the On period of the SMC Solenoidvalve, but they also can be broken up into two periods of the mechanical operation. If a gun is force fed, Through a Warp, it can achieve a VERY high ROF.

Finally the close time is when the Front Solenoid valve is turned off and the bolt moves back. This is set to allow the bolt to get all the way back before the hammer releases again. Timing this too short and you get blowback from the valve being open before the bolt is closed.

Okay, I will leave here at this point. I could go on about settings and how to get it short, but lowering the open/close times can really raise the ROF, and force fed systems can get great ROF due to being able to lower the load time.

Okay, it is really late, I have to be up in 6 hours or less and I have things to do. Have fun with these numbers, and I will keep my eyes in here to drop some more when I am not so busy. I can test stuff at the shop here and will be in the future. I will let you know my findings when I do.

Josh

Paladin, have you timed the cycle on your guns? The valve dwell time looks really short, and the cycle time has always been real mean. Just curious.

[Paladin]

Rate of fire

Hi Josh,

I don't have the electronic means to measure valve dwell and cycling speed. My tuning is all done by sound ,feel and seeing the results of firing.("Old-school technology, but it works) The valve dwell on our guns is VERY short (the primary reason we don't go in for the "low pressure" school of thought, no wasted gas, time or energy) and the operation of the gun is all based on what the valve is doing. The valve in our guns is designed to let the smallest burst of gas do the most amount of work possible in the shortest time possible. Then, the delay that is needed between firing and cycling can be very minimal without outrunning the system and getting the bolt open before the ball is gone.
On the Blazer, I had to design in a means to actually slow the cycling speed of the gun down in order for it to feed and function properly at high rates of fire. Ironically, slowing the gun down allowed for higher rates of fire and a shorter trigger pull.

[einhander619]

Congratulations, Vegeta, I think you have the basis down for the first paintball gatling gun!

[orangejulius]

If you are talking about the cycling and not firing the cocker just the cocker running the ram and bolt. Well ive played around with my racegun and has it clocking 50 BPS not firing just the backblock moving and gotten the gun up to 25 but do dont know if it has had shoot down. I think I will test this. If anyone does not believe me I will take a movie later.

[pbjosh]

Here is a little thought,

If we timed a cocker equipped with a power feed that matched the PF of a 'Mag, and added blowback into the timing, say set the gun Shot/Dwell to 4,4 and then use that blowback to Power the next ball into the feed, we could lower our Load setting also, so we could in fact run the gun with these settings:

4,4,20,20,15 which = 16.9 bps.

Wow, that would kick butt, put also feed well. I might have to get a power feed to fit on a Side fed 'Cocker.

Josh

[Paladin]

Timing the Blowback ??

How are you going to time the blowby to wait until the bolt is open so the ball can be blown into the breech??Blowby/blowback happens long befor the bolt is open far enough to feed a ball.
That would be like using the vent from the 4-way/ram to assit in feeding. When the bolt is open enough for that to happen, the ram would already be done venting so no air would be flowing when it needs to be.

Originally posted by pbjosh
Here is a little thought,

If we timed a cocker equipped with a power feed that matched the PF of a 'Mag, and added blowback into the timing, say set the gun Shot/Dwell to 4,4 and then use that blowback to Power the next ball into the feed, we could lower our Load setting also, so we could in fact run the gun with these settings:

4,4,20,20,15 which = 16.9 bps.

Wow, that would kick butt, put also feed well. I might have to get a power feed to fit on a Side fed 'Cocker.

Josh

[AGD]

See Glen I told you you'd like it here!

AGD

[Paladin]

Originally posted by AGD
See Glen I told you you'd like it here!

AGD

Hi Tom,
:) Yes indeed. It often get very interesting, to say the least. ;^)

[pbjosh]

Sorry I was very tired and just posted that to tease AGD.

And with the Racegun it is easy to time in blowback. I just have the bolt open way to soon. Or, not close before it starts another firing cycle. If I set the Shot to 4 ms and the Dwell to 4 ms I get blowback. Because the bolt IS coming back before the bolt/barrel have vented completely.

I know the bolt speed on the cocker is at least 20 ms to open, and the ball could never get loaded, but also if there is some blow back in the system that means the bolt is open, and on its way back, so the ball would most likely rebound into the outside edge of the bolt that is 1/2 to 3/4" open. Close but I realized it wouldn't quite make it.

As for ROF being above 13 bps, I will set a cocker up to do that reliably here in the future and run it by your table AGD at some future tourney. And we can play with the settings. I also want to build a sear and such that will allow me to test a Blazer. I have been a Blazer fan since it came out, and am very impressed with its performance. I bet it would be no problem to set it to 13+ with a good loader.

And with such things as the Tungsten Hammer Pro PB is handling now the cycle speed of the bolt/back block can be faster, because he uses a hammer spring that is suppose to be 1/10 the strenght of a a Nelson yellow. That could cut off up to 10 ms on the Open times on a lot of cockers. Yes that will add some time to the Shot dwell, but not 10 ms.

Also on the bolt/vent feedback issue, the ram won't be empty until the bolt is ALL the way back, right? And it might take a MS or two for the air to vent all the way into the the air assist feed. I could see where there is a window for the ball to be pushed into the breech. I am not saying it DOES happen, just that I see a potential window.

And I would also like to thank AGD for this forum. I like it here quite a bit too.

Josh

[Butterfingers]

the tungsten hammer also weighs a ton and a half. More reciprocating mass.

[Paladin]

Originally posted by Butterfingers
the tungsten hammer also weighs a ton and a half. More reciprocating mass.

Extra heavy hammers can have some benifits to consistency but can also lead to some interesting issues in tuning and timing the equipment. A very heavy hammer with a very light drive spring can in fact generate enough energy to get the valve open effectively but the time it takes for the hammer to get from the cocked position to the valve pin when released is increased significantly. Hence requiring signicantly different timing configuration to achieve decent shot performance.

[nerobro]

In other words you need to compensate for the "lag" it takes to open the valve.

Now.. what about going the other way. Using really really light hammers and going for efficancy.

didn't you use to sell light nelson hammers? And don't you try to have the spring totally exteneded by the time it hits the valve?

(I think I'm going for another thread here... ultimate sheriden efficancy...)

[Paladin]

Originally posted by nerobro
In other words you need to compensate for the "lag" it takes to open the valve.

Well, yes and it gets to be an interesting balancing act with the hammer and spring, as well as the size of the valve seat and the vavle spring to get the right opening distance and dwell. Then letting the valve do it's job before further cycling action.

Now.. what about going the other way. Using really really light hammers and going for efficancy.

"Really light" is usually too light. Especially with todays larger valve seats. Too light and you can't get the valve open against the pressure behind it without extreme overdrive with the hammer spring. Which in turn screws up dwell needs.

didn't you use to sell light nelson hammers?

Not really. That's probably Colin Thompson, LAPCO that you are thinking of. He even made them out of aluminum.
However I did use some of his lightened SS hammers in certain circumstances. The standard Nelson valve setup has many limitations as to what can be done with it so you had to be constantly changing springs to accomodate pressure changes from varying tempreatures. On the other hand, a nelson hammer has a very long fall before hitting the valve so you can get away with a lighter hammer.

And don't you try to have the spring totally exteneded by the time it hits the valve?

Yes. Actually, I try to get the spring fully extended about 1/8" before the hamer contacts the valve stem. That way the hammer can bounce off the valve and the valve is fee to work on it's own without the hammer/spring trying to hold it open when it wants to be closing. Allows for very accurate metering of air flow. If the hammer is too light or the valve seat too large, that is very hard to accomplish. Hammer weight variables as little as 1/2 gram or less can make a big difference in energy displaced on impact with the valve. The weight of the hammer and the distance that it travels are critical to accurate tuning. Keep in mind that the hammer has to work against the pressure in the valve and the valve spring actually only effects opening distance and valve dwell. There are many little tricks available for tuning valve output. like using a short, stiff little bumper spring inside of a light valve spring to allow for a large opening and short dwell on the valve.


(I think I'm going for another thread here... ultimate sheriden efficancy...)

Not at all. The same principles apply to all but a few of the guns in the game. There are only a few out there these days that do dot utilize a poppit style valve. Of course the Amag is one of those few