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Thread: How many times can an autococker cycle per second?

  1. #61
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    Cocker

    The main thing about a cocker is trying to overcome the inertis of the back block moving. this creates a problem since the forward motion is because of air pressure. then when to bolt moves back it will compress the air even more causeing a little lag there.
    noonagon@hotmail.com

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  2. #62
    Okay,

    I have seen the Back block take any where between 16 and 45 ms to open. This is timed on a Racegun Frame. And to close normally is 5-10 ms less.

    It was due to the Pressure input, ram, the linkage arrangment, bolt friction, spring weight, and also interia. Change any of these you can change the open/close time.

    Air trapped between the BackBlock has so little to do with it, it is funny. With the cocking rod out and decent components the back block goes back in about 15ms or less. Without the bolt it takes even less time.

    Josh
    "If you build it they will run" - pbjosh
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  3. #63
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    well, if u have to account for all that to get a cocker to shoot really fast what about the sandridge force 5 cocker, it was an electro cocker and they were saying how they could shoot so very fast. So does that mean when u have an electro frame or whatever it affects the moving parts of the gun? How can they make the cocker like that if they cant get it to shoot faster than one that isint electro?
    Skittle- Your partner in crime.

  4. #64
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    Originally posted by Skittle
    well, if u have to account for all that to get a cocker to shoot really fast what about the sandridge force 5 cocker, it was an electro cocker and they were saying how they could shoot so very fast.
    It IS an electrococker, and it does shoot fairly fast. It's a gun that's depenant on it's eye, and without it being set right, you often slow the gun down signifigantly.

    So does that mean when u have an electro frame or whatever it affects the moving parts of the gun? How can they make the cocker like that if they cant get it to shoot faster than one that isint electro?
    "electro" Doesn't really effect the operation of the gun. Just the trigger feel. the "electro" parts are just how soem people here are choosing to measure their guns.

    right now we know that a cocker can fire more than 20 times a seccond with palladins testing. So I suppose we are just down to the ponit of gettign a reg that can recharge that fast (the stabilizer can do 20... )

    I'm wondering waht fatter hoses will do for how fast the gun can be made to cycle. Currently I just crank up the pressure on my rock to keep the gun cycling as crisply as I like. (I use that term becasue that's the way the gun feels when a LPR is adjusted "right" Just like the blazer) Hmm... still need to build a test rig...
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  5. #65

    actualy

    Actualy some guy on PBC set his race frame to do 294.5 BPs and it cycled that fast.. if we are talking cycling as in the bolt cocking then firing then that is what i've heard.. ok now back to reality the feeding rate and trigger pull effect how many times a second.. i have gotten my cocker to 10 BPS and others with electro frames have gotten better just depends on the person....

  6. #66
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    ER and the rest of the new guys,

    You have posted in Deep Blue where we limit the discussions to factual and theoretical applications of physics to paintball. If you post something you MUST be ready to defend it with facts or a well thought out line of reasoning why it is true. If you post something you just HEARD was true, expect to get shredded here in this forum.

    ER, you claim that someone on PBNation had his cocker to 300 cycles per second. I counter with this line of .
    calcualtions.

    In order to have the bolt travel 1" forward and then 1" back 300 times as second it has to move at least 55 FPS with no accell, decell. Considering the regular cocker bolt speed is about 4 fps this means you need 10 times the bolt speed right off the bat.

    1" of forward travel at 55 FPS happens in about 1.65 milliseconds. This requires an accleration rate of about 16,000 feet per second, per second.

    To accelerate a 3 oz. bolt at this accel. rate you need 90 lbs of force.

    Cockers have a 1/4" piston for the bolt ram. To get 90 lbs of force out of it you would have to put 1900 psi air into the ram.

    Unless the ram was hooked directly into the main compressed air tank there is no way the gun could EVER cycle 300 times a second.

    So I claim the guy that posted that was either lying to get you to believe him or too stupid to figure it out for himself and is just passing down the myth.

    Please hang around and help us dispell the myths that permiate paintball.

    AGD

  7. #67
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    Physics is phun(nice job by the way, TK!), but I have a much simpler explanation - misplaced decimal.
    294.5 = 29.45?
    Perhaps it takes someone who is as bad at typing as me to think like this. I hope against hope that noone is ignorant enough to claim 300 cycles per second on a cocker.
    Last edited by einhander619; 05-28-2002 at 10:06 AM.
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  8. #68
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    it is SO hard to get a cocker over 9pbs. now i admit that i dont own one. but i have tried my friends old one, and the trigger and bolt just wont allow u to fire anything close to what er has stated. i am not a math/physics wizz like tk, but i can say this with complete assurance. this could be different w/ a racegun however.
    Arggggh

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  9. #69

    hey

    all i was saying was some guy set his to that on the race.. he said it didnt look like it was moving so it probably wasnt.. but there are also guys that set their cockers to 90 on FA and the back block was a blur according to them.. now am i saying this is a fact no.. just what i have heard. i cant say the facts because for me the fastest i have gotten my cocker with sliding slotted trigger was 10 bps...

  10. #70
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    90 bps sounds a little more plausible, still nuts, though! I think I'm going to forward this thread to my physics prof, he'll probably make a test question out of it. Even if a cocker did 90 bps, it probably couldn't sustain it for more than a few seconds before it would simply fly apart! Now, Tom, I didn't do the math, but following your example, 90 cycles a second would take something on the order of around 600 psi input pressure to the ram, correct? So much for low pressure...

  11. #71

    mike

    ok i worked out your calculations and my ff with an input of under 300 which cycles at 30 psi is able to cycle at 47.5 bps so why would it be that impossible?? also at 90 it wouldnt fly apart.. cockers are built sturdy they arent the beasts many of you think they are...

  12. #72
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    Using Tom's explanation as a basis, I've come up with the following set of calculations. I included acceleration of the bolt since it wasn't too difficult to calculate. I will use the example provided by ER FFballa 8 to illustrate:

    Take your cycling pressure (30 psi) and convert it to atmospheres by dividing by 14.7 psi/atm.

    30 / 14.7 = 2.04 atmospheres.

    Take this value and convert it to Pascals (a.k.a. N/m^2) by multiplying it by 101325 Pascals/atm

    2.04 * 101325 = 2.07x10^5 N/m^2

    We will assume that this pressure is constant against the cocker's ram piston. According to Tom's post, the piston is 0.25 inches in diameter (6.35x10^-3 meters). Calculate the area occupied by the piston.

    (3.1415 / 4) * (6.35x10^-3)^2 = 3.167x10^-5 m^2

    Calculate the force on this piston as a result of the gas pressure.

    2.07x10^5 N/m^2 * 3.167x10^-5 m^2 = 6.56 N

    F = m * a, a = F/m, calculate the acceleration of the bolt, assuming a weight of 3 ounces (mass of 0.0850 kg)

    6.56 N / 0.0850 kg = 77.2 m/sec^2

    Find how long it takes for the bolt to move 1 inch (0.0254 meters) with the acceleration calculated above.

    x = 1/2 a t^2

    t = sqrt(2 x / a)

    t = sqrt(2 * 0.0254 / 77.2) = 0.0257 seconds

    Multiply this time by 2 to cover an entire bolt open/close cycle.

    0.0257 * 2 = 0.0514 seconds

    This is the time required for one cycle of the bolt. Take the reciprocal of this number to determine the number of cycles per second, assuming zero delay between changes in bolt direction.

    1 / 0.0514 = 19.5 cycles/second

    At 30 psi, the max rate I calculate is 19.5 cycles per second. Using the 1900 psi in Tom's post, I get a max rate of 155 cycles per second. The max cyclic rate varies with the square root of the pressure, all other factors (bolt mass, piston diameter, bolt travel) being constant. Quadrupling the pressure increases the max cyclic rate by a factor of two.

    BJJB

  13. #73
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    Originally posted by MrMag
    it is SO hard to get a cocker over 9pbs. *snip* and the trigger and bolt just wont allow u to fire anything close to what er has stated. *snip* this could be different w/ a racegun however.
    Your difficulty in getting a cocker over 9 bps is your hand, not the gun.

    The trigger is something you can tune to allow yourself to shoot the gun as effectivley as YOU can. the bolt has little to do with the rate of fire of th gun, at the ROF you're mentioning.

    Using the racegun frame has almost no effect on maximum rate of fire. All it does is use a solinoid for the sear and one for the 4way. As the parts of the gun see it, the differences are negligable at best. The sear drops faster... and that's about it.

    As paladin said earlier, he has had one of his guns up to 20bps... so we know THAT number for sure.

  14. #74
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    IIRC the piston in a stock cocker is 3/16" not 1/4" That changes things singifigantly. the only ones with the 1/4" or smaller are the clippard minirams...

  15. #75
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    If I am reading my own calcs correctly, the max cyclic rate varies proportionally with piston diameter. In this case, a 3/16" piston should yield 75% of the cyclic rate obtainable by a 1/4" piston, all else being equal.

    BJJB

  16. #76
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    1/4"= .25"

    ok.. radius times radius time pi..

    .125x.125x(pi)=0.04908 square inches...

    3/16"= wait.... eep... the math in my head just glitched really badly. I was thinking 3/8" *crawls back into his hole*

    http://www.clippard.com/store/displa...asp?sku=3SD-3T

    Isn't that what the clippard rams are? not the minirams..... the fittings look the right size. if that's true... then it has 2x the piston aera.

    3/8" gives us .1sq inch of aera... Doubble what the ram in the calculations gave us.. so we get doubble the force for the same pressure.

  17. #77
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    Re: actualy

    "At 30 psi, the max rate I calculate is 19.5 cycles per second. Using the 1900 psi in Tom's post, I get a max rate of 155 cycles per second. The max cyclic rate varies with the square root of the pressure, all other factors (bolt mass, piston diameter, bolt travel) being constant. Quadrupling the pressure increases the max cyclic rate by a factor of two. "

    155 cycles/sec. now lets calculate bolt mass into that. it is going to be harder to move taht block of aluminum back iand forth, tehre is a thing here on earth called gravity. In a vacuum, thats another thing. So that will slow down the cycles , but also teis thing has to reciprocate and therefore it has to accelerate in the beginning of each stroke, deccel when it is about closed,and accel again, etc etc. That will shave soem time off there. \


    But what wetre looking for here is this:

    A object with a mass of 500g when moving at 1 m/s is goign to have more kenetic energy than a object with a mass of 250g moving at 1m/s. i.e. it takes longer for a 18,000 poung 18 wheeler to stop than a 2,000 pound Nissan. Now taht recipricationg mass should be semi good, becuase at a certain spot it should start to help keep the cycling going thtat fast, i.e.bouncng back and forth. So makign hte bolt lighter will increase the cycle rate .. but how light is too light? will a medium wieght bolt give the cycling more enerygy than a lgiht bolt and therefore allowing the gun to cyccle faster?

    I dunno. Now that I think about it, not really. But maybe if the bolt and linkage rod was lengthened, and there was a spring put between the block and hte body, so at high speeds it would bounce? no... thats nto a real good idea.. teh gun wouldnt stay in the cocked position.

    just brainstorming here ppl dont kill me.

  18. #78
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    neobro wrote:
    >
    > 3/8" gives us .1sq inch of aera... Doubble what the ram in the
    > calculations gave us.. so we get doubble the force for the same
    > pressure.

    3/8" is 1.5 times 1/4". The area will be 1.5 * 1.5 = 2.25 times that of a 1/4" piston, and will be able to push with 2.25 times the force at the same pressure. This means that the acceleration is 2.25 times as fast, which means that the time required to travel one inch is the square root of 2.25 times faster than for a 1/4" piston. The square root of 2.25 is 1.5, which is identical to the ratio of the two piston diameters. The cyclic rate varies proportionally with piston diameter, all other things being equal.

    On the topic of max cyclic rate with an input pressure of 1900 psi, vegeta wrote:
    > 155 cycles/sec. now lets calculate bolt mass into that.

    I used a total reciprocating mass of 3 ounces, as stated by Tom.

    > it is going to be harder to move taht block of aluminum back iand
    > forth, tehre is a thing here on earth called gravity.

    Gravity should not affect the reciprocating speed unless you're starting to talk about frictional effects against the bottom of the bolt's chamber.

    > In a vacuum, thats another thing.

    I'm confused. This did not follow from your previous sentance regarding gravity.

    > So that will slow down the cycles , but also teis thing has to
    > reciprocate and therefore it has to accelerate in the beginning of
    > each stroke, deccel when it is about closed,and accel again, etc
    > etc. That will shave soem time off there.

    I took into account acceleration from a resting position for each direction of the stroke. Deceleration at the end of each stroke is the result of a hard stop, particularly in the case of the forward stroke. Because I treated the deceleration as a hard stop, I assumed it was effectively instantaneous.

    > Now taht recipricationg mass should be semi good, becuase at a
    > certain spot it should start to help keep the cycling going thtat
    > fast, i.e.bouncng back and forth.

    The only way you're going to get a bouncing back and forth effect is if you can find a means to store the kinetic energy at the end of each stroke and can vent the pressure that caused each stroke quickly.

    > So makign hte bolt lighter will increase the cycle rate .. but how
    > light is too light?

    Absolutely. A lighter bolt should increase the max cyclic rate in proportion to the square root of the old bolt/new bolt ratio. As for how light is too light, I'd have to say so light that it affects the structural integrity of the bolt.


    BJJB

  19. #79
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    When I mentioned gravity, i was talking about the bolt having wieght. And when I said vaccum i mean space, not vacuum... thats totally diffrent, sorry.

    Now friction on the bottom of the bolt from gravity itself I wasnt directly talking about but could be an issue. I mainly meant that mass of bolt moving back and forth. What if the gun was cycling in a zero gravity enviroment? what effects would this have on the parts?

  20. #80
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    Well, things got lively didn't they?

    AGD

  21. #81
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    well i was just thinking and came upon this thought. running a pball gun at 90 fps would require constant oil on the bolt and internals to prevent too much friction. now unless he was pouring oil down into the gun durring the entire time, i dont see how this would be plausbale. the bolt and internals would create so much friction everything would simply be destroyed.

  22. #82
    Okay, this is all fun and such, but a couple of comments,

    Yes this got nice and busy fast. Way to go guys.

    Uhm, 30 psi in a ram is rarely enought to cock it. Try 60-90 as the standard.

    Also most Rams are made to run at 125-250 psi for a million cycles without lube.

    The limiting factor for the total speed has more to do with other factors such as side load, hammer spring tension, total mass, and other junk. Just running the bolt back and forth at 70 psi or so still takes 15-20 ms each way on most guns without the cocking rod. I have tested an Open time to be reliable and cocking at the 20 ms level. But that was a really smooth setup. And at medium pressure.

    If you set the Racegun to 7 ms for the open time the back block jumps about 1/2" to 3/4". Without a cocking rod it ALMOST might move close enough to load a paintball, if the back block was screwed out enough for the bolt to be almost at the breech opening when the the bolt was all the way forward.

    Also if you use Racegun's RIP software the highest setting, at 1 ms for each or the 5 areas, you get 250 bps. The gun doesn't cycle at those settings boys. Just barely makes some really cool clicking noises.

    I can get a gun to dry cycle at 18-22.5 bps, but that is with 1 ms to load paint. There is NO floating of the valve or anything, just a really fast angel scaring sound.

    And the Racegun's Half-Blocks hammer, bolt, and top-block weight about the same as the standard fomieless bolt I have in my mag. I don't have #s, but it was darn close. I will try and measure when I get mine in.

    As for timing the cockers with the Racegun Frame, You can test and set every portion of the grip to match EXACTLY how fast your gun does go. And sometimes that is alot slower than we think. I have sent guns out that could do 11.95 with a good VL and faster with a HALO. And ones that have an Eye that do even better than that. Most of them? 9.5 bps MAX. About 60% can do better than that. But I haven't seen any that run at less than 9.0 bps. Not a 1.

    I will let everybody know what my Halfie does with an Eye and the Warp feed. AGD, got any any you want to donate for testing? I might not be able to hit 20 bps, but something close.

    Josh

  23. #83
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    Josh

    Im running racegun at 9bps. I am running a stock ram at 25 or its maybe around 28 ish PSI stock hammer just some special springs. I play all day like that and test it at home and it runs fine at that PSI loads fine doesnt pinch or chop in the whole day. running 250 shooting 290 stock bolt everything is stock besides the cocking rod P reg and the raceframe everything else is stock. Im feedinging it with a maxflow tank. and I dont even have a heavy hammer just stock.
    orangejulius

  24. #84

    as for weights..

    a 2k1 STO backblock, bolt, and recocking rod are right at 109 grams. i actually made a bolt, backblock and recocking rod that weigh 27 grams, which is pretty much the same as the 25-30 grams of the shortblocks'.

    with the stock STO 109 gram setup and a 74 gram tungston FF hammer, my race will shoot at 11 bps all day. have yet to try pushing the 27gram setup for speed, but it will do 13bps.

    btw- PP/RaceGuns had some pretty nice setups at skyball 5 this year:
    http://home.viptx.net/~colin/day2/03020039.JPG
    pbjosh were you there??

    out!
    ColinMoritz

    Chord, Chord V2, Dallara, Karta, current project: (coming soon)

  25. #85
    Nope, I was at Vegas, and should be at Chicago. And I will have a working Halfie there with one of Tom Kaye's Warps on it. I am hoping for 15+.

    I should be hitting all the Major tourneis and some other events here and there this next year, and after that I will be VERY busy next year. I currently plan on hitting NWTS, Pan-Am, NPPL/PSP, and maybe all the fun ones inbetween, like Skyball, Mardi Gras, IAO, plus a couple of Racegun Events. Hopefull I will get to play in a big game or two, maybe some thing fun and senario. Right now I am busy getting everyting setup, but I will let ya know.

    And hopefully I can see your gun.

    Josh

  26. #86

    well

    that is a vertibrate with a race i believe (actualy allmost positive..).. best race cocker i have seen/shot was ethans (from lockout) millenium race.. that thing was amazing.. mitchs son was lighting people up with it and hes like 10 it was funny as hell.. anyways back to the subject yeah like i said i run 30 psi to the ram and about 270 to the 'gun i get 10 on a slider.. planing on getting a race then pushing it to its ultimate max and then ill tell you guys what i got it to.. btw my cocker is a 2k2 boxxer ff.. next time i think of it ill throw the back block and bolt on the digi scale and tell you guys the wieght of it...

  27. #87
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    Damn this did get hot fast. I wish I had a cocker/racewframe so I knew more about this stuff.

  28. #88
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    I've had 4 RaceGuns, that all max dry-cycle'd at around 16-19bps.

    They've been two Milleniums, Spanky Fishbone Mini, and Works, so we're talking fairly light markers & components.

    Just from my personal experience, I'd say 30 or 300 is impossible, but we'll see where the halfie leads.

    PBJosh, what inline were you using to get 22bps? I found that after about 14bps an ANS Gen-X couldn't keep up, and switched to a MacDev Gladiator.

    Just as an aside to other RaceGun owners, I'm comfortably shooting 12bps, without any real need to see if I can tweak it to play faster. I didn't realize I could shave off some time on the Close, I might fiddle w/ that

    Also, is anyone doing shot or dwell lower than 6?
    ------------------
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  29. #89
    Well, the guys at Compulsive Paintball Shot this vid and let me host it.

    So, please, use 'Save Target As' to keep from slowing down the server.

    http://www.amped-markers.com/video/racemovie1.avi

    This is a Merlin Racegun with the Eye, running FA fed by a HALO. Notice he starts shooting at 10 sec, and stops at 21, and only has a couple of paintballs in the loader. The gun is set to 15.5, and he said it was hardly breathing, might have to open it up a bit more.

    I have heard of a Warp fed gun going 18+ with paint, but at that speed you start worrying about parts falling off. as soon as I get my Half-Block, that is what I aim to shoot. I got the Warp, just need the Halfie.

    Josh

  30. #90
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    the boston paintball reflex trigger is capable of 14 a second. i know this becouse i just ordered mine. ohh god i cant wait
    micromag
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