Author Topic: HPA Project .. a dilema  (Read 1078 times)

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Offline dezyboy

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HPA Project .. a dilema
« on: January 28, 2012, 02:26:03 PM »

As some will know I have been doing a ratchatch high pressure air project , the air tank is slowly coming from America in the shape of a 3000psi in and a regulated 1400psi output bottle.

Everything I have wanted to do so far has not been a problem , as I have either known what to do or have been able to work it out.

The dilema..

Right , with 1400 psi constantly in the rifle .. if I get it right, then each shot will not vary by much at all (in theory as good as any regualated pcp)

So what would work better .. ?

Hard Hammer Spring and a hard valve spring  (a hard hammer hitting a light valve spring may cause valve bounce, leaking air each bounce)
Soft Hammer spring and soft valve spring the theory being the 1400psi behind the valve would shut the valve and have enough force to keep it shut without bounce occuring.  Making for a smoother quieter action.


What would you go for ?  and does my reasoning sound along the right lines to you ?

Gareth the Welsh Lamb sexpert.

Offline Gambo

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Re: HPA Project .. a dilema
« Reply #1 on: January 29, 2012, 10:45:03 AM »
It's all going to depend on the design/flow of what the exhaust valve will give.

If you go with too heavy a hammer spring, you will have to use a small transfer port to keep it under 12ftlbs, than as the cylinder pressure drops, the port cannot flow enough  volume of the lower pressure air to maintain that power, and so the gun will drop off it's charge early.

Likewise, the opposite will happen with too weak a hammer spring.


So, it's a bit of a balancing act to try to get the hammer spring, valve spring, and the transfer port size all correct, to best enable control of the air volume/pressure being passed on to the pellet.......so it's probably going to take a fair bit of trial and error to get it just right.

All three components must work in harmony with each other.

You might be lucky though, and find a good setting straight away....fingers crossed for you mate.......as it can be VERY frustrating constantly emptying/stripping/rebuilding/refilling the gun all the time, just to shoot a full charge over the chrono to see how it goes.

Offline dezyboy

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Re: HPA Project .. a dilema
« Reply #2 on: January 29, 2012, 07:31:51 PM »
hmm yeah , a selection of springs required and a few spares to butcher.

Gareth the Welsh Lamb sexpert.