How do high level PCP guns work?

[jhatfie4]

Brand new member here. When I was a kid, I made an 12' long pneumatic potato gun. It had a 10' power section of 4" CPVC (wrapped with old blue jeans, bc I couldn't access pressure rated), with a one way piston check valve made from scratch with PVC drains, rubber diaphragm, and spring. This valve would seel the barrel from the pressure chambers. Once the rear pressure chamber was dumped, the piston would slide back and expose the barrel entry to the main power chamber.

If this isn't how the nice guns work, then I'm going to make my own with this style, because it was capable of making dehydrated potato flakes at above 120psi.

 

[6gun]

Brand new member here. When I was a kid, I made an 12' long pneumatic potato gun. It had a 10' power section of 4" CPVC (wrapped with old blue jeans, bc I couldn't access pressure rated), with a one way piston check valve made from scratch with PVC drains, rubber diaphragm, and spring. This valve would seel the barrel from the pressure chambers. Once the rear pressure chamber was dumped, the piston would slide back and expose the barrel entry to the main power chamber.

If this isn't how the nice guns work, then I'm going to make my own with this style, because it was capable of making dehydrated potato flakes at above 120psi.

It's even more nuanced than that. There's many valve types. High end pcps are far better than a pneumatic spud gun with a diphram valve that dumps all of its propellant charge indiscriminately..... Except for vacuum canons. You have much reading to do if so inclined. Fwiw I could disintegrate potatoes or send them super sonic if sufficiently hard and green and frozen with an 8 foot gun I made in my teenage years with a coil spring and a ball valve(very rudimentary valve) . I had a smaller version that shot dead c batteries incredibly far too.

Precision and consistency are the point of high end pcp guns... And nice fab work. I've got a challenge for you if you want to make something. Make a spool valve gun with electric eyes on it that won't let the breech close till you have ammo loaded. I've got a gun design I want to try when I've got balanced and cobra chamber valves securely understood. Air waste, dirty air behind the projectile and shot count is another part of high end pcps. If it's raw power you want, it's thick wall seamless tubing and tig welder time with energy levels that are hard to wrap the mind around. Even I skipped making a 3k psi pool ball mortar

Check out some of the creative systems used in high end paintball guns over the years too.

 

[jhatfie4]

It's even more nuanced than that. There's many valve types. High end pcps are far better than a pneumatic spud gun with a diphram valve that dumps all of its propellant charge indiscriminately..... Except for vacuum canons. You have much reading to do if so inclined. Fwiw I could disintegrate potatoes or send them super sonic if sufficiently hard and green and frozen with an 8 foot gun I made in my teenage years with a coil spring and a ball valve(very rudimentary valve) . I had a smaller version that shot dead c batteries incredibly far too.

Precision and consistency are the point of high end pcp guns... And nice fab work. I've got a challenge for you if you want to make something. Make a spool valve gun with electric eyes on it that won't let the breech close till you have ammo loaded. I've got a gun design I want to try when I've got balanced and cobra chamber valves securely understood. Air waste, dirty air behind the projectile and shot count is another part of high end pcps. If it's raw power you want, it's thick wall seamless tubing and tig welder time with energy levels that are hard to wrap the mind around. Even I skipped making a 3k psi pool ball mortar

Check out some of the creative systems used in high end paintball guns over the years too.

Cool! I found the exploded view of the Benjamin Bulldog. Where can I go to get schematics of other PCP's? Also, my education is Aerospace and Mechanical, but I can do a little bit with microcontrollers/programming/sensors, and even can build simple neural networks from scratch. A neural network could find patterns between operating parameters and performance.

 

[beerthief]

Cool! I found the exploded view of the Benjamin Bulldog. Where can I go to get schematics of other PCP's? Also, my education is Aerospace and Mechanical, but I can do a little bit with microcontrollers/programming/sensors, and even can build simple neural networks from scratch. A neural network could find patterns between operating parameters and performance.

sounds like you can be a cool addition to the forum . Welcome to the best A G N

 

[jhatfie4]

sounds like you can be a cool addition to the forum . Welcome to the best A G N

Thank you! I've been pondering how to use converging/diverging nozzles to increase performance, but unfortunately the simulation in my head says that any supersonic flow would undergo conversion back into heat once the flow met the projectile. I'm not 100% sure tho. You'd need a ton of pressure to choke a flow that has a projectile. I suspect that shotgun chokes may do this. I'm pretty new to guns that don't shoot vegetables.

 

[sb327]

Welcome to agn.

Things to keep in mind when comparing potato canons to PCP’s.

1. Larger calibers can make more power but at what point is it just too big?

2. Longer barrels can make more power, but again, see above.

3. We try to use a very high density projectile so we can impart as much energy as needed. Potato’s aren’t very dense in relation to lead. Point being, it wouldn’t take much to get a .22 caliber potato up to speed but the power itself would be low.

Good luck with your endeavors down the pcp rabbit hole, especially with valve design. There are too many types of valves to go over in one post here but there are some cool ones. Besides the common knock open poppet, search for balanced valve. It is a variation of the knock open and is used in several newer platforms.

Dave

 

[boscoebrea]

Relax and have a open mind.Read up on all the information you can.There have been advances and maybe in time you may come up with some of your own. It is better to read all the information you can before you ask.....

 

[6gun]

Cool! I found the exploded view of the Benjamin Bulldog. Where can I go to get schematics of other PCP's? Also, my education is Aerospace and Mechanical, but I can do a little bit with microcontrollers/programming/sensors, and even can build simple neural networks from scratch. A neural network could find patterns between operating parameters and performance.

Google image search fx impact exploded diagram. That's a good one a bunch of conventional thoughts rearranged. When I read your post I thought of the bulldog valve I saw last night. Looking at the 20 mm helium powered 1 off gun might be fun too.

 

[jhatfie4]

Welcome to agn.

Things to keep in mind when comparing potato canons to PCP’s.

1. Larger calibers can make more power but at what point is it just too big?

2. Longer barrels can make more power, but again, see above.

3. We try to use a very high density projectile so we can impart as much energy as needed. Potato’s aren’t very dense in relation to lead. Point being, it wouldn’t take much to get a .22 caliber potato up to speed but the power itself would be low.

Good luck with your endeavors down the pcp rabbit hole, especially with valve design. There are too many types of valves to go over in one post here but there are some cool ones. Besides the common knock open poppet, search for balanced valve. It is a variation of the knock open and is used in several newer platforms.

Dave

perfect that's what I will look at!

 

[jhatfie4]

Google image search fx impact exploded diagram. That's a good one a bunch of conventional thoughts rearranged. When I read your post I thought of the bulldog valve I saw last night. Looking at the 20 mm helium powered 1 off gun might be fun too.

sweet thanks! FX's are cool

 

[oldmojo]

Aeaairguns.shop and fox air power have prints on aea guns, im not a fan of there power wheel design FYI. But if your going for potato flakes there no need to adjust power down so I'd omit that from the design

 

[jhatfie4]

Aeaairguns.shop and fox air power have prints on aea guns, im not a fan of there power wheel design FYI. But if your going for potato flakes there no need to adjust power down so I'd omit that from the design

I'm looking for ultimate efficiency. I want the energy of every pump that I perform with my muscles to be imparted into the target. Thanks! I want to understand how to make the AEA guns reliable.

 

[6gun]

sweet thanks! FX's are cool

My recent wormhole has been making basic poppet valve guns perform better than they should. The cobra air spring valve is one im learning about with captured hammer springs and some hammer free flight. I have a mill and a small lathe and get bored easily. My fx guns are "too easy" to make work well. The pursuit of as near to perfection as possible is more their strong suit.

I like making things that shouldn't do stuff do it well. So next I'm going to borrow from the paintball gun world myself for behind the valve components

 

[6gun]

Aeaairguns.shop and fox air power have prints on aea guns, im not a fan of there power wheel design FYI. But if your going for potato flakes there no need to adjust power down so I'd omit that from the design

I'm still bitter about their half cooked engineering on the hpss poppet I had to fix with 1 more machine operation

 

[Gerry52]

WELCOME ABOARD! "I want to understand how to make the AEA guns reliable." You & a lot of other people who've bought them!
Most airgun manufacturers have exploded diagrams under support if you go directly to their websites. (You inquired about schematics. ) "A neural network could find patterns between operating parameters and performance." That basically sounds like Daystate electronic guns. They do all the figuring for you.

 

[sb327]

I'm looking for ultimate efficiency. I want the energy of every pump that I perform with my muscles to be imparted into the target. Thanks! I want to understand how to make the AEA guns reliable.

Efficiency can be measured in fpe/ci of air used. Air volume is at atmospheric pressure.

If you are going to start making pcp valves, I suggest getting a compressor. Hand pumping and design/fabrication don’t go together in my opinion, lol.

As for AEA….they are basically just overdriven, meaning they generally use a knock open poppet driven extremely hard to produce as much power (selling point) as possible. They, imo, are just hotrodded too much for that type of valve. They could be made just as powerful with a more elegant valve but then they would lose their price point.

Dave

 

[jhatfie4]

Efficiency can be measured in fpe/ci of air used. Air volume is at atmospheric pressure.

If you are going to start making pcp valves, I suggest getting a compressor. Hand pumping and design/fabrication don’t go together in my opinion, lol.

As for AEA….they are basically just overdriven, meaning they generally use a knock open poppet driven extremely hard to produce as much power (selling point) as possible. They, imo, are just hotrodded too much for that type of valve. They could be made just as powerful with a more elegant valve but then they would lose their price point.

Dave

ahh... great info! Yeah I'm only doing hand pump because I like the exercise, and this is how I'll have to do it in a survival situation most likely. Also, I haven't built my aluminum CNC yet, but perhaps a resin printer will provide the accuracy and strength needed for many components