 |  | | | |  | |  |  | Regulated Disco Valve |  | |  |  | |
 Posted: Thu Feb 23, 2012 3:47 pm |
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| rsterne |
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| Joined: 15 Jan 2008 |
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| Location: Coalmont, BC |
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Last year I made a regulator that attaches directly to a Disco valve.... I was working on different ways to produce a non-PAL PCP (ie under 500 fps).... It did the job by using a shortened 2240 valve spring.... Here's what it looks like....
It replaces the front end of the valve, and is long enough to cover the roll-stamped area on a 22XX tube.... I used the piston and spring from a Ninja regulator, so the parts are easy to obtain, in fact I just bought a Ninja rebuild kit to get them.... The back half of the valve, including the poppet and spring, are stock....
I installed it into a 2260 tube for testing.... I found the velocities more consistent with a lightened hammer (I went all the way to 30 gr. - 50% of stock).... Here is the shot string....
It appears that the regulator setpoint with just the spring (no shims) is about 650 psi.... I was quite pleased with the flatness of the shot string, 55 shots averaging 492 fps with 14.3 gr. JSB Express pellets, and the efficiency worked out to 1.21 FPE/CI.... I also tried it with a stack of Belleville washers (disc springs), and with a setpoint of about 1350 psi it gave 10 shots averaging 773 fps (19 FPE) with an efficiency of 1.13 FPE/CI.... The limited number of shots at higher power is because of the 2000 psi fill limit.... It only left 650 psi available, which is only 168 CI (at 1 bar) with a 2260 tube.... You could double that shot count by using a Disco tube.... but in reality there is little point.... Regulators are at their best when the setpoint is low enough to utilize a much wider range of pressure.... Having said that, shimming the coil spring a bit and bringind the setpoint up to about 1000 psi should give a good shot count and velocities in the high 600s.... Adjusted the way it is would produce a non-PAL Disco with over 100 shots per fill....
Bob |
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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal: Too many to count! |
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| Posted: Thu Feb 23, 2012 4:15 pm |
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| radar |
| Silver Status Member |
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| Joined: 13 Nov 2011 |
| Posts: 1138 |
| Location: Des Moines, Iowa, USA |
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Now that has potential! What a beautiful string. I'm thinking it could be marketed as either a PAL or non-PAL for shot consistency.
You sir, are a steely-eyed airgun genius! |
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It's never too late to have a happy childhood. |
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| Posted: Thu Feb 23, 2012 5:54 pm |
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| domer_pyle |
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| Joined: 17 Sep 2009 |
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| Bob is my airgun idol lol, he seems to know everything I want/need to know |
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| Posted: Thu Feb 23, 2012 8:34 pm |
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| robert w |
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| Joined: 12 Feb 2012 |
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| Location: usa |
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,crosman 400,gamo big cat in .22, diana 5g,diana 54 air king, diana 34 in .22 diana 34 in .177, wilrauch hw-55,and a romainian pioner training rifle , and a huge collection of powder burners 35 last count . 1 would think i have a gun store |
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