Lurker27
07-18-2004, 01:29 PM
Cross Post form tinkerers guild.
I was thinking of another project to do, when an idea popped into my head. For prototyping, it can be based on a spyder.
The idea is to chop off the front of a spyder bolt (delrin would be best, since it needs to slide nicely) and make a small (delrin) plate to seal the breech from the feedtube (trap door design, pretty standard). Air is constantly fed through the body hole of the spyder via a plugged blowback port in the valve and lack of a valve pin/cupseal assembly.
The cycle is run through the ACE. When a ball is detected, the breech is sealed by the plate, which, since it doesn't require much force, could be run directly by a low-power solenoid (solenoid could be held closed via spring and energized to open to save batteries).
The firing cycle itself would use a vertically oriented ram to rotate the bolt assembly , briefly lining up the inlet of the valve with the body hole and allowing a burst of air through. I'm thinking enlarged body ports are in order, and the the body hole would be lined with 'liquid gasket' to provide a good seal. Because only one ram is needed to trigger the firing cycle, any old board would do.
You might be thinking that the problem you'd run into is efficiency, but, if one were to have a bolt with 2 ports and a ram stroke such that the rotational action was ratcheting and turned the bolt 180*, you'd have a dwell that was transitive, rather than reciprocating. This would lead to shorter dwell times, but at full flow. Creative structuring of the port could help to even out the graph of flow over time during a syzygy of the 2 holes. (Naturally, it is a bell curve with the most flow in the middle)
I think that this could help to solve the efficiency problem, by packing a very short dwell in. in most other markers, short dwells decrease valve dwell, but also can decrease flow by not opening the poppet as far. In theory, LP air could be dumped quickly and allowed to expand adiabatically behind the ball, while the bolt continues rotating to seal off the barrel making for an extremely efficient marker. Hopefully you could get the air dumped and the valve closed again before the ball leaves the barrel.
Also, because there is no obstruction in the breech, in lieu of detents one could create a C-shaped UHMW barrel insert (running the entire length of the barrel) that clamps when the ACE sees a ball (again, the default position could be closed, set with a spring and relaxed via a solenoid when a ball is not detected). The clamping UHMW insert would provide for a perfect paint to barrel match with each shot, improving consistency, accuracy and efficiency. UHMW is a flexible but reasonably strong, slick and hard material (harder than a paintball) that would be good for this application. since you know the relationship of the bore in relationship to the paintball with every shot, you can do interesting things like applying internal rifling and be sure the ball is taking the spin, or purazor blades set ever so slightly out of thwe UHMW sleeve to slit paintballs ever so slightly, increasing their chance of breakage on target.
The characteristics I can see provided by this design:
Speed. No reciprocating mass in the pneumatic cycle, so CPS is limited only by the ram.
Kick. Should be nonexistant, as the only reciprocating part is the breech sealing plate, which should weigh no more than a paintball.
Efficiency. If leaks can be avoided, you can the potential for a very short dwell at high flow rates. That spells efficiency, to me.
Accuracy. This has more to do with the barrel concept, but if rifling could be successfully applied, (and there's no reason it can't, in theory) you'd have a deadly accurate marker, since every paintball had the barrel clamp specifically to it.
Size. The bottom tube is not required. If the ram was located in the frame (not unrealistic since it sits veritcally) and no LPR wa used (ala SP) you could have a complete valving system aobut the size of a mag valve.
Complexity. A definate disadvantage, here. The face seal that the rotating valve necessitates is hard to accomplish. The ACE would control so much, you'd have to have them super reliable and be able to see through paint. WAS eyes do half of that. the ratcheting system would have to be very reliable and consistent, as well. Teh trap door must be carefuly placed as to not become a ball guillotine.
Battery Life. Using solenoids to open the breech and relax the barrel/detent system will suck up juice, but probably no worse than an E-spyder since neither enterpise takes much work (Force x distance) I don't imagine electrical shootdown would be a big problem.
Choppage. Since nohing solid contacts the ball, there shouldn't be any. Since the barrel will size even to the odd balls in the batch you shouldn't get too many breaks. The ACE should help too.
I'd love to hear what you guys think of this pipe dream.
I was thinking of another project to do, when an idea popped into my head. For prototyping, it can be based on a spyder.
The idea is to chop off the front of a spyder bolt (delrin would be best, since it needs to slide nicely) and make a small (delrin) plate to seal the breech from the feedtube (trap door design, pretty standard). Air is constantly fed through the body hole of the spyder via a plugged blowback port in the valve and lack of a valve pin/cupseal assembly.
The cycle is run through the ACE. When a ball is detected, the breech is sealed by the plate, which, since it doesn't require much force, could be run directly by a low-power solenoid (solenoid could be held closed via spring and energized to open to save batteries).
The firing cycle itself would use a vertically oriented ram to rotate the bolt assembly , briefly lining up the inlet of the valve with the body hole and allowing a burst of air through. I'm thinking enlarged body ports are in order, and the the body hole would be lined with 'liquid gasket' to provide a good seal. Because only one ram is needed to trigger the firing cycle, any old board would do.
You might be thinking that the problem you'd run into is efficiency, but, if one were to have a bolt with 2 ports and a ram stroke such that the rotational action was ratcheting and turned the bolt 180*, you'd have a dwell that was transitive, rather than reciprocating. This would lead to shorter dwell times, but at full flow. Creative structuring of the port could help to even out the graph of flow over time during a syzygy of the 2 holes. (Naturally, it is a bell curve with the most flow in the middle)
I think that this could help to solve the efficiency problem, by packing a very short dwell in. in most other markers, short dwells decrease valve dwell, but also can decrease flow by not opening the poppet as far. In theory, LP air could be dumped quickly and allowed to expand adiabatically behind the ball, while the bolt continues rotating to seal off the barrel making for an extremely efficient marker. Hopefully you could get the air dumped and the valve closed again before the ball leaves the barrel.
Also, because there is no obstruction in the breech, in lieu of detents one could create a C-shaped UHMW barrel insert (running the entire length of the barrel) that clamps when the ACE sees a ball (again, the default position could be closed, set with a spring and relaxed via a solenoid when a ball is not detected). The clamping UHMW insert would provide for a perfect paint to barrel match with each shot, improving consistency, accuracy and efficiency. UHMW is a flexible but reasonably strong, slick and hard material (harder than a paintball) that would be good for this application. since you know the relationship of the bore in relationship to the paintball with every shot, you can do interesting things like applying internal rifling and be sure the ball is taking the spin, or purazor blades set ever so slightly out of thwe UHMW sleeve to slit paintballs ever so slightly, increasing their chance of breakage on target.
The characteristics I can see provided by this design:
Speed. No reciprocating mass in the pneumatic cycle, so CPS is limited only by the ram.
Kick. Should be nonexistant, as the only reciprocating part is the breech sealing plate, which should weigh no more than a paintball.
Efficiency. If leaks can be avoided, you can the potential for a very short dwell at high flow rates. That spells efficiency, to me.
Accuracy. This has more to do with the barrel concept, but if rifling could be successfully applied, (and there's no reason it can't, in theory) you'd have a deadly accurate marker, since every paintball had the barrel clamp specifically to it.
Size. The bottom tube is not required. If the ram was located in the frame (not unrealistic since it sits veritcally) and no LPR wa used (ala SP) you could have a complete valving system aobut the size of a mag valve.
Complexity. A definate disadvantage, here. The face seal that the rotating valve necessitates is hard to accomplish. The ACE would control so much, you'd have to have them super reliable and be able to see through paint. WAS eyes do half of that. the ratcheting system would have to be very reliable and consistent, as well. Teh trap door must be carefuly placed as to not become a ball guillotine.
Battery Life. Using solenoids to open the breech and relax the barrel/detent system will suck up juice, but probably no worse than an E-spyder since neither enterpise takes much work (Force x distance) I don't imagine electrical shootdown would be a big problem.
Choppage. Since nohing solid contacts the ball, there shouldn't be any. Since the barrel will size even to the odd balls in the batch you shouldn't get too many breaks. The ACE should help too.
I'd love to hear what you guys think of this pipe dream.