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 Post subject: Combo springer/pcp
PostPosted: Tue Apr 05, 2016 6:47 am 
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Joined: Mon Aug 24, 2015 4:56 pm
Posts: 462
Location: Tecumseh, Ontario in South Western Ontario
First I'd like to say I read the 'Sonic Choke or Sonic Joke' thread on the GTA and was totally humbled. I don't think I can contribute there but appreciate the level of sophistication these guys are adding to our sport science.
I do have a good imagination though and whether it's sound or just amusing I hope you find this post worth reading.
My latest idea is a combination springer and pcp. For a pcp to be efficient it needs to let in no more air from the tube than is necessary to propel the pellet most of the way down the barrel at a reasonable velocity. The problem is the pressure might start out pushing the pellet with say 3000psi but quickly drops of to no beneficial pressure by the time the pellet gets to the muzzle.
Now imagine a basic springer gun. In this case the piston isn't being pushed back by a lever but by the air pressure in front of it from an air tube so that it's ready to shoot forward when the pressure is released. The pressure in the chamber and the sprung piston is held back by a trigger activated, quick release dump valve as near the pellet as possible.
Now the sprung piston will help keep up the pressure to push the pellet all the way down the barrel.
--Ed.


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pcp springer combo.png
pcp springer combo.png [ 9.13 KiB | Viewed 986 times ]

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 Post subject: Re: Combo springer/pcp
PostPosted: Tue Apr 05, 2016 9:00 am 
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Posts: 3320
Location: Central West River Nova Scotia
Let me be the first to congratulate you for submitting your design idea. If, for no other reason, it shows you enjoy the sport and are wanting to make it better. Whether or not your design is good or a waste of time, is irrelevant. It inspires others to think outside the box, and, initiates discussion, either positive or negative, which bring,s to light, technical issues with compressed air driven projectiles, that everybody should know, who takes this sport seriously. I'm sure there are thousand,s of closet inventor,s, who never get past the idea stage, or, they simply give up when technical issues come up, and aren't willing, or aren't capable of working past them. My mantra is "you wont know till you try". Good luck.

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 Post subject: Re: Combo springer/pcp
PostPosted: Tue Apr 05, 2016 10:47 am 
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Joined: Sat Nov 03, 2007 4:19 pm
Posts: 8978
Location: Coalmont BC
Somewhat similar to the Webley Paradigm, except instead of a PCP reservoir, it was a pumper.... The spring was a stack of Belleville washers, which a piston loaded up, storing energy in addition to that in the compressed air, both of which are released during the shot.... It can be made to work on a small scale, but when you scale it up, you run into two issues.... The spring required becomes massive, and therefore heavy, and the piston also gets big and heavy, and you have to deal with stopping it at the end of the shot.... You can solve the former by using a chamber of compressed air instead of the spring, and in fact you can use a piston of two different diameters to boost the pressure in the system as well.... but you still have to deal with stopping the mass of the piston without damaging it or the gun....

As in most ideas like this, the devil is in the details.... but well done thinking about it.... Perhaps you will be clever enough to solve the peripheral issues and make it practical.... Good Luck !!!!

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
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 Post subject: Re: Combo springer/pcp
PostPosted: Wed Apr 06, 2016 4:15 pm 
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Joined: Mon Aug 24, 2015 4:56 pm
Posts: 462
Location: Tecumseh, Ontario in South Western Ontario
joe hickey wrote:
Let me be the first to congratulate you for submitting your design idea. If, for no other reason, it shows you enjoy the sport and are wanting to make it better. Whether or not your design is good or a waste of time, is irrelevant. It inspires others to think outside the box, and, initiates discussion, either positive or negative, which bring,s to light, technical issues with compressed air driven projectiles, that everybody should know, who takes this sport seriously. I'm sure there are thousand,s of closet inventor,s, who never get past the idea stage, or, they simply give up when technical issues come up, and aren't willing, or aren't capable of working past them. My mantra is "you wont know till you try". Good luck.

Thanks Joe,
The fact is I've been a construction and a factory worker all my life and have no more machining tools than a hack saw and a hand drill. I guess I like throwing out my ideas hoping someone finds them interesting. As Bob says the 'Devils in the details' and I believe that's true. I finally have an idea I can build and test so stay tuned.
I feel bad about the RobertMcC incident. I guess one advantage of being an old cute is our skin has thickened considerably.
--Ed.

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 Post subject: Re: Combo springer/pcp
PostPosted: Wed Apr 06, 2016 5:07 pm 
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Joined: Sun Jan 29, 2012 7:31 pm
Posts: 696
Location: Halifax, NS
^^x2 thinking outside the box. Interesting post & concept, shall definitely try & follow .. hope you continue with updates!

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 Post subject: Re: Combo springer/pcp
PostPosted: Wed Apr 06, 2016 8:52 pm 
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Joined: Sun Jan 09, 2011 8:07 am
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Location: Central West River Nova Scotia
Tools are going to be essential.

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 Post subject: Re: Combo springer/pcp
PostPosted: Wed Apr 06, 2016 10:08 pm 
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Joined: Sun Jul 15, 2012 10:49 am
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Location: Victoria, BC and Clarkston, WA
Ed, do you have the link to that conversation on the other forum?

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 Post subject: Re: Combo springer/pcp
PostPosted: Thu Apr 07, 2016 1:01 am 
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Joined: Mon Aug 24, 2015 4:56 pm
Posts: 462
Location: Tecumseh, Ontario in South Western Ontario
rrdstarr wrote:
Ed, do you have the link to that conversation on the other forum?


Yes it's,

topic72008.html

I see they have locked out the thread.

Also Joe and Goodenough, when I said 'I finally have an idea I can build and test so stay tuned.' I must have forgotten what thread I was on because I didn't mean I could build the gun I attached above. Actually I have a NEW idea for a type of pellet/bullet that I don't need special tools to make.

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 Post subject: Re: Combo springer/pcp
PostPosted: Thu Apr 07, 2016 5:11 am 
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Joined: Sun Jan 09, 2011 8:07 am
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Location: Central West River Nova Scotia
That,s too bad. I wanted to see how you overcome the dump valve and trigger setup.

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 Post subject: Re: Combo springer/pcp
PostPosted: Thu Apr 07, 2016 6:41 am 
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Joined: Mon Aug 24, 2015 4:56 pm
Posts: 462
Location: Tecumseh, Ontario in South Western Ontario
Actually Joe I've been thinking a lot about a reusable fast opening mechanical dump valve that doesn't seem to exist yet or at least I can't find one on the net.
The first thing I thought of was a heavily sprung, heavy duty camera aperture. The pellet could be right up to it but the HPA on the other side would cause a lot of friction between the plates and the air would leak through.
The second idea which I like the best so far is a barrel sized hinged trap door that snaps open from the HPA when the latch is released. The pellet would have to be a little further away but it might be a good compromise. It would seal well up against an O ring.
The third would be like the double sliding doors we regularly walk through in stores. Again the pellet could be right on the other side and again the friction from the HPA would be a challenge. Maybe the doors could be supported by roller barings but leaks would be hard to stop.
What we need Joe are some of these clever machinists I know are on this site that like to tinker instead of watching reruns on the TV.
When we create a short list of ideas we could draw up some basic plans and maybe someone will build and test them.
--Ed.

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 Post subject: Re: Combo springer/pcp
PostPosted: Fri Apr 08, 2016 5:20 am 
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Joined: Sun Jan 09, 2011 8:07 am
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Location: Central West River Nova Scotia
That's the reason I asked. Dump valves that can handle 1500 psi and up, are difficult to design. Then you have to find a way to open the valve with linkage to a trigger, then you have to figure a way to close the valve again and reset the trigger. What looks and sounds like a good idea on paper, get,s a lot more complicated, when you try to figure out how to build, how to install it and how to make it work.
The bleed valve in your design, is easy enough to make, and would serve OK for filling the chamber for each shot manually. However, the dump valve is another matter. You could use a ball valve, but finding one small enough to withstand the pressure, and still be able to open it, would be the hard part. Also, a ball valve can't really be opened fast enough to be affective for high speed projectile,s. Many have tried using springs and such. Finally, you have to figure out, how you would load the pellet.
I'm sure, with the right minds behind a design like yours, and with the right machinery, it could be done, but a closet inventor with no tools, and limited knowledge in fluid mechanic,s, might be in over your head.
I mean no disrespect. I'm speaking from experience.

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 Post subject: Re: Combo springer/pcp
PostPosted: Fri Apr 08, 2016 6:07 am 
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Joined: Mon Aug 24, 2015 4:56 pm
Posts: 462
Location: Tecumseh, Ontario in South Western Ontario
The design below would open instantly when the latch is spun. It would fall back into position when the pressure equalizes and the latch can be reset for the next chamber fill.
No I don't have the tools or skills to build it but I enjoy throwing my ideas out there for discussion.
--Ed.


Attachments:
Dump valve.png
Dump valve.png [ 9.19 KiB | Viewed 772 times ]

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