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0.22" mini piston hybrid

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Unread postAuthor: POLAND_SPUD » Fri Sep 09, 2011 1:36 pm

Why would this work
there are no orings on the piston so it should equalise
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Unread postAuthor: ramses » Fri Sep 09, 2011 2:05 pm

POLAND_SPUD wrote:
Why would this work
there are no orings on the piston so it should equalise


You will still probably need a spring, otherwise the piston will never be motivated to move forward to seal (until you depressurize the fill rig). There would be equal force on both sides of the piston.
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Unread postAuthor: POLAND_SPUD » Fri Sep 09, 2011 3:06 pm

You will still probably need a spring, otherwise the piston will never be motivated to move forward to seal (until you depressurize the fill rig). There would be equal force on both sides of the piston.
Hmm I guess you're right

A spring would be useful... though the filling rig would neeed a pin for depressing the piston as the cartridge is filled



Personally I think that a detent based cartridge would be better...

though it's hard to tell what is better a detent based cartridge that has issues with sealing or a more complicated and difficult to build piston based cartridge
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Unread postAuthor: Labtecpower » Fri Sep 09, 2011 3:48 pm

A spring would be useful... though the filling rig would need a pin for depressing the piston as the cartridge is filled


The spring doesn't have to be unnessecarily strong. It only has to hold the piston forward, it doesn't need to hold back ignition pressure. Due to the relatively large piston surface, it won't take much pressure to move the piston in order to fill the cartridge.
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Unread postAuthor: POLAND_SPUD » Fri Sep 09, 2011 4:18 pm

Due to the relatively large piston surface, it won't take much pressure to move the piston in order to fill the cartridge
mind you the ID of the barrel is 5.5mm

for a pneumatic it wouldn't be a big deal... but a spring will have an effect on fueling
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Unread postAuthor: jackssmirkingrevenge » Sat Sep 10, 2011 1:30 am

Here's the basic idea for filling:

1) cartridge placed in rig, and fuel (calculated to give a correct ratio for a correct mix taking the fill rig volume into account as well) is injected

2) the rig is capped and taken up to correct pressure. There are no airtight parts in the cartridge so both chamber and "pilot" are pressurised.

3) the rig is depressurised through the schrader, and the pressure imbalance causes the piston to shut, sealing off the cartridge.

A weak spring keeping the piston shut would be helpful with reliability though...

Will try to conjure up a prototype today.
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Unread postAuthor: Moonbogg » Sat Sep 10, 2011 2:47 am

Sounds like a creative and new idea to me. I'm looking forward to seeing it come together or at least see it in an experimental stage.
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Unread postAuthor: jackssmirkingrevenge » Sat Sep 10, 2011 5:53 am

POLAND_SPUD wrote:Personally I think that a detent based cartridge would be better...

though it's hard to tell what is better a detent based cartridge that has issues with sealing or a more complicated and difficult to build piston based cartridge


That fact is inescapable. A coaxial piston cartridge of given dimensions will invariable be more complex to put together and be less powerful than a "valveless" cartridge of equivalent size.

Hmmm...
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Unread postAuthor: POLAND_SPUD » Sat Sep 10, 2011 8:00 am

yup... orings


orrrrr

if it works for copper it should work for lead :-D
Image

not sure if it would be better to use the projectile itself as the seal or would you need a seperate olive...

the more I think about this the more the better the idea seems
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Unread postAuthor: Brian the brain » Sat Sep 10, 2011 1:58 pm

Why not fill the cartridge through the barrel port?
Thread it and you don't need the rig thing.

You might even be able to put it in a compression fitting whilst filling....

I would throw in the spring though.
It will keep that portion of the gas from escaping that split second of decompressing the barrel port.
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Unread postAuthor: jackssmirkingrevenge » Sun Sep 11, 2011 2:53 am

Brian the brain wrote:Why not fill the cartridge through the barrel port?
Thread it and you don't need the rig thing.


I had contemplated this for another design but the fill rig is a one time build and allows for a much cleaner cartridge

I would throw in the spring though.
It will keep that portion of the gas from escaping that split second of decompressing the barrel port.


For the piston design a small spring would definitely be helpful.

POLAND_SPUD wrote:the more I think about this the more the better the idea seems


I proved it works a while ago.

No need for compression fittings though, the projectile should be forced into a smaller bore. Airgun pellets are typically oversided for their calibre to ensure a good seal.

Here's a thought, avoiding threaded fittings instead having a "full bore" rear plug o-ringed and held by pins for full access and the ability to load the projectile from behind, which would also work for a silicone seal.
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Unread postAuthor: jackssmirkingrevenge » Sun Nov 06, 2011 12:16 am

Giving this a bit of thought again for a pen gun cartridge for starters, looks like it has reasonably good prospects, especially compared to the equivalent HPA pen gun.
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Re: 0.22" mini piston hybrid

Unread postAuthor: hectmarr » Fri Jul 22, 2016 2:54 pm

I'm new around here, and after reading this, I have been admired by the passion they put into their work without any doubt, I have learned a little, since I'm just initiating me in this of hybrid gun
Despite cost me a lot to understand the language, my English is very basic, the translator helps me to read and write, I would love to discuss this. I keep reading and watching ... Greetings
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Last edited by jrrdw on Sun Jul 24, 2016 5:14 pm, edited 1 time in total.
Reason: Edited for content.

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