Airgun Theory Pressure Washer PCP Airgun Fun

[Tims]

I was thinking about PCP airguns. I had just installed a new Carbon Fiber tank and upgraded valve on my Airforce Texan. I now had my original tank and valve to use for a project! What I noticed about the Airforce system is its efficiency and simplicity is fantastic! So where does the power washer come in you ask? The short answer is that I like the simplicity and efficiency concept and the power washer offered cheap, simple, and fairly efficient means to deliver air to a barrel of my choosing. Hydraulic hoses make for decent durable pathways for air and they are fairly inexpensive. power washer valves are suitable for controlling plenum loading and they are rated at 300 bar or higher and they are cheap. So what happened to the Texan tank and valve? Didn't need it. The pressure washer gun valve and trigger are already to go. The input hose to the pressure washer gun(PWG) serves as the plenum. The discharge hose from the PWG output side delivers the plenum air to the barrel when the trigger is pulled. At this point I am loading via a hollow through bolt that screws into the barrels breech plug. barrel is a 26.5"CVA Firebolt Ultramag,.51 Cal, 1:28 twist, inline black powder barrel. Not my first choice because of the slow twist rate; it was cheap and I am cheap and this is a cheap project (if ya know ya know!) I machined an adapter to carry the fill nipple, pressure gauge and Plenum charging valve that attaches to a .38L tank that holds apt 2-3 full power shots at 3200psi. I tether to a regulated tank to keep the gun filled to 3200psi(regulated sort of). Today I embarked on a mission to increase airflow by removing restrictions where possible. As of this writing I have discovered that the swivel hydraulic fittings are very restrictive, the JIC fittings are very restrictive, the PWG fittings are very restrictive, The quick connect fitting on the through bolt is horribly restrictive, etc...... That said; This Air Rifle already worked well. Can't wait to correct these restrictions and see the improvements(I Hope!)

 

[Awl In]

I was thinking about PCP airguns. I had just installed a new Carbon Fiber tank and upgraded valve on my Airforce Texan. I now had my original tank and valve to use for a project! What I noticed about the Airforce system is its efficiency and simplicity is fantastic! So where does the power washer come in you ask? The short answer is that I like the simplicity and efficiency concept and the power washer offered cheap, simple, and fairly efficient means to deliver air to a barrel of my choosing. Hydraulic hoses make for decent durable pathways for air and they are fairly inexpensive. power washer valves are suitable for controlling plenum loading and they are rated at 300 bar or higher and they are cheap. So what happened to the Texan tank and valve? Didn't need it. The pressure washer gun valve and trigger are already to go. The input hose to the pressure washer gun(PWG) serves as the plenum. The discharge hose from the PWG output side delivers the plenum air to the barrel when the trigger is pulled. At this point I am loading via a hollow through bolt that screws into the barrels breech plug. barrel is a 26.5"CVA Firebolt Ultramag,.51 Cal, 1:28 twist, inline black powder barrel. Not my first choice because of the slow twist rate; it was cheap and I am cheap and this is a cheap project (if ya know ya know!) I machined an adapter to carry the fill nipple, pressure gauge and Plenum charging valve that attaches to a .38L tank that holds apt 2-3 full power shots at 3200psi. I tether to a regulated tank to keep the gun filled to 3200psi(regulated sort of). Today I embarked on a mission to increase airflow by removing restrictions where possible. As of this writing I have discovered that the swivel hydraulic fittings are very restrictive, the JIC fittings are very restrictive, the PWG fittings are very restrictive, The quick connect fitting on the through bolt is horribly restrictive, etc...... That said; This Air Rifle already worked well. Can't wait to correct these restrictions and see the improvements(I Hope!)View attachment 22859View attachment 22860View attachment 22861

OK that is freaking awesome!!! What could possibly go wrong?!

 

[Chief55]

I am looking for a high-pressure valve to replace the standard valve that came on the Talon tank so I can use the top hat kit. Where did you get your high-pressure valve?

 

[Pumacarl]

That would be great if l lived on the moon, I think most of my airguns are too heavy to begin with. It is a super cool project though, great use of what you have and know, to make your own fun! Kudos!

 

[Tims]

I am looking for a high-pressure valve to replace the standard valve that came on the Talon tank so I can use the top hat kit. Where did you get your high-pressure valve?

The Airforce Carbon Fiber tank upgrade came with a new valve

 

[Tims]

I have discovered that there were many many sources of air flow restriction in my design. some were simple to remedy; some not so simple. I dreamed up a new design utilizing the same basic parts. Had to order some new parts in order to proceed. While I waited for parts I was able to assemble another Pressure washer Parts PCP Air Rifle in 9mm. I incorporated the lessons learned from the .51 caliber gun into the new 9mm gun. The Plenum is no longer a hydraulic hose. There is a plenum tank connected to the input of the pressure washer gun that holds a one shot, full power, amount of air. the 9mm barrel threads into the output side of the pressure washer gun; eliminating another hose from the .51 cal design and eliminating lots of air flow restriction. I'm anxious to rework the .51 cal gun since I have base line results that will help me determine if the new design is an improvement or not!
I am experimenting with the barrels and slug friction in both of these guns. I have machined different sizing dies. I believe that the .51 cal slugs are too tight for the CVA black powder barrel that I am using. I am concerned about the 9mm barrel having too tight of a twist? I will have to experiment with slug sizes to see what works. I will have a great collection of 9mmish sizing dies when I'm done!
I attached some not so good photos of the new 9mm project

 

[Tims]

I have discovered that there were many many sources of air flow restriction in my design. some were simple to remedy; some not so simple. I dreamed up a new design utilizing the same basic parts. Had to order some new parts in order to proceed. While I waited for parts I was able to assemble another Pressure washer Parts PCP Air Rifle in 9mm. I incorporated the lessons learned from the .51 caliber gun into the new 9mm gun. The Plenum is no longer a hydraulic hose. There is a plenum tank connected to the input of the pressure washer gun that holds a one shot, full power, amount of air. the 9mm barrel threads into the output side of the pressure washer gun; eliminating another hose from the .51 cal design and eliminating lots of air flow restriction. I'm anxious to rework the .51 cal gun since I have base line results that will help me determine if the new design is an improvement or not!
I am experimenting with the barrels and slug friction in both of these guns. I have machined different sizing dies. I believe that the .51 cal slugs are too tight for the CVA black powder barrel that I am using. I am concerned about the 9mm barrel having too tight of a twist? I will have to experiment with slug sizes to see what works. I will have a great collection of 9mmish sizing dies when I'm done!

 

[Pumacarl]

I have discovered that there were many many sources of air flow restriction in my design. some were simple to remedy; some not so simple. I dreamed up a new design utilizing the same basic parts. Had to order some new parts in order to proceed. While I waited for parts I was able to assemble another Pressure washer Parts PCP Air Rifle in 9mm. I incorporated the lessons learned from the .51 caliber gun into the new 9mm gun. The Plenum is no longer a hydraulic hose. There is a plenum tank connected to the input of the pressure washer gun that holds a one shot, full power, amount of air. the 9mm barrel threads into the output side of the pressure washer gun; eliminating another hose from the .51 cal design and eliminating lots of air flow restriction. I'm anxious to rework the .51 cal gun since I have base line results that will help me determine if the new design is an improvement or not!
I am experimenting with the barrels and slug friction in both of these guns. I have machined different sizing dies. I believe that the .51 cal slugs are too tight for the CVA black powder barrel that I am using. I am concerned about the 9mm barrel having too tight of a twist? I will have to experiment with slug sizes to see what works. I will have a great collection of 9mmish sizing dies when I'm done!
I attached some not so good photos of the new 9mm project

I love your work area! It just screams of a 1000 past projects. Figuring it all out is so rewarding. Stuff like what you are doing is the heart and soul of a hobby that makes it more than just a pastime. It's an adventure, and you're working without a net. Kudos. I really miss reading all of Bob Sterne's projects he used to do. Everybody bringing a different take to it makes it interesting. Keep it up, I appreciate you taking the time to post about it too.