is it the seals

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   Theory would have it that if your piston has enough force to load the pressure chamber through the port, it's probly going to be strong enough to seal the chamber and no none return valve needed. 

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kruzaroad Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 02 Jul 2022 Location: Hastings 4 now Status: Offline Posts: 1686	Post Options Post Reply Quote kruzaroad Report Post Thanks(0) Quote Reply Posted: 26 Aug 2022 at 2:44am
	Theory would have it that if your piston has enough force to load the pressure chamber through the port, it's probly going to be strong enough to seal the chamber and no none return valve needed.

xyon Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 20 Dec 2016 Location: Canterbury Status: Offline Posts: 133	Post Options Post Reply Quote xyon Report Post Thanks(0) Quote Reply Posted: 26 Aug 2022 at 6:28am
	Don't want kill your creativity 😜 But there are a couple of reasons why the valved springer would not work well. If you store the air at the end of the piston stroke. Then you do have a single stroke pneumatic, which we all know is quite a bit less powerful than a spring rifle. Why is that? Can you guys tell me 😁 The pellets in a spring rifle acts as a kind of valve. The pellet holds in the breech until the pressure is high enough to force it into the barrel. The volume of the transfer port on a springer must be as small as possible for high efficiency. If you go adding valves and crap between the piston and the pellet, the efficiency and power will suffer.
	--- My favourites springer - Diana 52 PCP - FX Wildcat III

kruzaroad Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 02 Jul 2022 Location: Hastings 4 now Status: Offline Posts: 1686	Post Options Post Reply Quote kruzaroad Report Post Thanks(0) Quote Reply Posted: 26 Aug 2022 at 9:19am
	I thought that's what we were talking about. A single shot. I be keen to know why a high pressure chamber storing the equivalent amount of air as the piston chamber ( more actually as there's the air in the chamber before compression) would produce less power than a piston alone. But I guess pump action take more than I stroke. Still larger piston chamber to smaller the pressure chamber higher the pressure. Don't worry about stifling my creativity, I'm just throwing ideas out. Just a mind exercise. I'll look further into air compression facts see what I'm dealing with.

kruzaroad Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 02 Jul 2022 Location: Hastings 4 now Status: Offline Posts: 1686	Post Options Post Reply Quote kruzaroad Report Post Thanks(0) Quote Reply Posted: 26 Aug 2022 at 11:46am
	From what I've managed to piece together from the Web the compressing air to chamber is sweet, it's a simple formula. I'll do some calculations later probly from hw97@45cc and Diana 350@70.8cc. The real energy sapper seams to be the heat produced between the piston and reciever and the port. They reach really high heats, 700+ this expands the air, converts energy to heat, (tighter the port more the heat) when that cools in the chamber, its of a lesser volume. Actual lose still to be found out. I'll post a link to a boyles law calculator for anyone interested http://www.endmemo.com/chem/boyle.php Edited by kruzaroad - 26 Aug 2022 at 11:50am

xyon Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 20 Dec 2016 Location: Canterbury Status: Offline Posts: 133	Post Options Post Reply Quote xyon Report Post Thanks(0) Quote Reply Posted: 26 Aug 2022 at 1:58pm
	You're right, the springer makes the air very hot, but it does not have much time to transfer the heat anywhere, so the pressure peak acting on the pellet is very high, but as the pellet moves down the barrel the air expands and cools again. For a single stroke pneumatic, the heat is lost, that means part of your pumping energy is lost. So when you pull the trigger on a SSP the air is expanding and getting cold and decreasing in pressure more quickly. Edited by xyon - 26 Aug 2022 at 1:59pm
	--- My favourites springer - Diana 52 PCP - FX Wildcat III

kruzaroad Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 02 Jul 2022 Location: Hastings 4 now Status: Offline Posts: 1686	Post Options Post Reply Quote kruzaroad Report Post Thanks(0) Quote Reply Posted: 26 Aug 2022 at 4:26pm
	Any idea of the equation or a site I can use, to find out what the temps get too? Knowing that I could work out the decress in air. I have a simple design in my head to keep heat to a minimum entering the pressure chamber. At 45cc the the air compressed to a third made 2bar approx.( no loss from friction or cooling in that) If I can alculate the loss I can adjust the storage volume for when cooled. Oh a barrel has been sent to me today free of charge. Off a returned gun with mag problems. sweeeeet

mercs Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 24 Apr 2020 Location: Stratford Status: Offline Posts: 243	Post Options Post Reply Quote mercs Report Post Thanks(0) Quote Reply Posted: 26 Aug 2022 at 5:47pm
	Good luck with the barrel, and sensible option from Gamo supplier, I am pleased they followed through. Look forward to a much improved rifle. My fusion is a scope buster so I was interested in what you found with the spacer washer. Mine is a .177 and actually shoots quite well using fixed sights. Agree I would rather lose energy to gain accuracy and scope longevity. cheers

kruzaroad Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 02 Jul 2022 Location: Hastings 4 now Status: Offline Posts: 1686	Post Options Post Reply Quote kruzaroad Report Post Thanks(0) Quote Reply Posted: 26 Aug 2022 at 6:01pm
	I'm more than happy with the spacer washer out. It's 5mm and it added thump to the forward stroke. It was a noticeable difference. I had to use a gclamp and washers to recompress it. So there is pressure there from the start. I actually hate to think how much harder it was hitting. I was just reading an artical I stumbled on looking for friction info, about the affect of a harder springs (and gas rams in particular) having more effect on recoil when the initial jolt of the ram releasing, the than the end of stroke.

Billbobnz Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 13 Jun 2020 Location: Ashburton Status: Offline Posts: 778	Post Options Post Reply Quote Billbobnz Report Post Thanks(0) Quote Reply Posted: 26 Aug 2022 at 9:12pm
	Pauly5, you have actually brought up another idea I've had.... I've also thought for a long time at having the piston firing backwards a bit like a rifle sized version of a Webley pistol but having a fixed barrel and side lever would be easy to make a bullpup version and still have a full length barrel.

Billbobnz Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 13 Jun 2020 Location: Ashburton Status: Offline Posts: 778	Post Options Post Reply Quote Billbobnz Report Post Thanks(0) Quote Reply Posted: 26 Aug 2022 at 9:20pm
	Xyon, yes you are right it would have a big impact on power output. But I would rather a slower accurate pellet (say 550-600fps in .22) over a faster inaccurate shot. The thing that wouldn't work is having a regulator that would allow the high flow during the shot cycle, Nothimg would be worse than having a delay in the shot cycle Does anyone know the pressure that the piston builds up in a brake barrel?