 |  | | | |  | |  |  | A closer look at the powermax-hipac |  | |  |  | |
 Posted: Thu May 13, 2010 5:51 pm |
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| Jaxom |
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| Joined: 06 Aug 2008 |
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Honestly this thread could go in several different forums. I thought it bes to put it here so more folks could contribute.
I am aware the orginal designer has posted on here and was eventually banned because he didn't ask to post commerical advertizment and even more so refused to answer any questions about his product.
I do however like the concept. I'm wondering if we could make something simlar that wouldn't have the same safety issues as the powermax has. Most notibly is his advertisment of increase power, "with no other modifications nessary". As we've discussed in multiple threads, I would be leary of his product alone because he never disccuses that a stock 22xx valve only has one mounting screw.
Another issue of great importance that we here have discussed is how 22xx tubes are roll stamped. Should the seal on the powermax fail, this could cause a potential critical falure as the tube explodes sending bits of metal flying. Still, I think we could come up with something simlar here that would be safier then the powermax.
Before I continue, let's take a closer look at the powermax. Here'a close up photo that's been posted on the net....
Although I don't have first hand expirence doing machine work. It looks to me this was made from frome a single piece of round bar stock. Machined down to fit insdide the 22xx's gas tub and threaded where needed inorder to install.
Since I'm most interested in using a modified version of this in my 2300kt, there's a few things I want to point out. I'll be replacing the valve from my discovery with a modified valve from Croooked Barn. I'll then install the discovery valve in my kt, mounting it with 3 screws! Also of note the gas tub on my kt has all the lettering laser etched rather then roll stamped.
Unlike 22xx's that use co2 carts, like my kt is set up now, the discover valve does away with needing to punchure the cart. I can do away with all that extra bit that goes inside the tube. I would mainly need an extention of sorts that was machined to the same diameter as the current tube, and then threaded so I can just screw it on.
To make sure there was no leaking where the current tube and the extention meet, add in some O-rings. I also noticed on the end of the powermax there's a nut that the quick connect is screwed into, I could use that nut to really tighten down the extention make sure there was no leaks.
About the only other thing I would see nessary, because this would extend the tub another 7" beyond the current end of the gas tube would be adding another barrel strap. I sappose we could get fancy and add in a pressure guage and maybe even thread the end so a discovery type cap could be screwed on to cover the quick connect.... But all in all I don't see this as being a very difficult project. I just wish I had more expierence doing machine work...and well, having the tools would be nice!
Suggestions? Comments?
Jax |
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.22 2300kt Crosman Custom |
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| Posted: Thu May 13, 2010 7:58 pm |
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| rsterne |
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| Quote: |
| It looks to me this was made from frome a single piece of round bar stock |
I disagree, it looks to me like there is a joint just outboard of the threaded portion.... this would shorten the distance needed to be bored as there is no practical way to make a vessel a larger ID in the middle than at the ends.... The only other alternative is to bore it out from the very front end which I think unlikely.... A boring bar long enough would have way too much flex....
Since your proposed project would use a Disco valve and the tube does not have the roll-stamp issue, we can make the assumption that you can safely pressurize the tube to a maximum of 2000 psi.... That is the safe working limit for 7/8" OD x 0.065" wall mild steel tubing.... It is also the design pressure for the Disco valve installation (assuming that all three screw heads take an equal load).... The only thing wrong with this assumption is that we do not know the specifications for the tubing that Crosman uses.... so as always, only YOU can decide whether to proceed or not safely....
There are fill adapters made which can screw right into the threads on the front of your tube.... B&A also make an extension tube (8 3/8" long) that threads in and increases the volume.... It is intended for CO2 use, but assuming a reasonable safety margin.... and the fact that CO2 pressures can reach 1900 psi at 120*F.... that should work OK.... You can find both the bulk-fill adapter and the extension tube here:
http://www.bryanandac.com/default.htm
Both the B-F adapter and the extension tube are sealed with O-rings.... purchasing them would be cheaper than making your own.... A standard male foster fitting will screw right into the B-F adapter.... 
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: Sat Sep 11, 2010 9:55 am |
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| justforfun |
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| Joined: 08 Aug 2007 |
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I found this thread and wondered about the item. I contact Alex and ask him some questions.
WOW what a guy, he almost bi my head of, saying "of course to a question", guess he thought I already should know the answer.
People like that should not try to be in business.
Needless to say, he will never see any of my money.
Roy |
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| Posted: Sat Sep 11, 2010 1:50 pm |
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| broommaster2000 |
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Welcome aboard Roy!  |
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| Posted: Sat Sep 11, 2010 6:43 pm |
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| kanyon |
| Silver Status Member |
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| Joined: 09 Aug 2008 |
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| Location: New Zealand |
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hi..
Yer right bob..looks like it made in 2 sections...
Now these 22xx valve that give people nightmeres about how they are held in....they are held buy the screw & port...at 2 points not one..
If you have 3000psi in the bottle/tube what ever yer wish to call it..
There is NOT 3000psi trying to push the valve out the rear of the gun..
the surface area in the valve is WAY less than 1 square inch..
In fact there would be less than 1000psi of pressure trying to push the valve....Most lightly only a few hundred pounds..
Its the same as a bleed valve in yer 3000psi pcp fill unit...
How can you turn the bleed valve/screw with your fingers if there 3000psi of presure forceing against it.....well theres NOT 3000psi forceing against it...It has a VERY small surface area...so theres only a few lbs of presure on it...
If the bleed hole has a surface area of 1 sq/mm..and theres 3000psi of presure.....lets do the numbers...
area...1sq/inch = 645.1 sq/mm
3000psi devided by 645.1 = 4.6lbs per sq/mm...
and thats why yer can open the bleed valve with yer fingers..
same applys to the 22XX valve trying to be shot out the rear of the tube..
It just an't going to happen...probly over tighting the powerlet front cap
will apply more pressure on the valve the the air dose..
Pete |
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Career Infinity PCP .22
Webley Patriot .25
Hatsan mod 75 .22
Hatsan mod 99 .177 (Quattro & SAS)
Kral underlever .177
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| Posted: Sat Sep 11, 2010 7:42 pm |
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| rsterne |
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I agree with your numbers 100%.... unless the seal in the front end of the valve fails.... IF that happens suddenly the tube would be pressurized.... Yes, it can leak out around the valve through the sear and hammer slots.... What happens if it can't past the valve fast enough?.... IMO it could result in catastrophic failure.... This is the argument I had with the inventor of the HiPac....
If you assume the seal area is about 1/4" across the end force is about 147 lbs. @ 3000 psi.... The safe working load of the 6-40 screw in shear is about 176 lbs.... Since the transfer port only presses on the side of the valve I don't think it does much to anchor it.... IMO it's a safety issue as the 29 lbs. of safety margin could easily be used up by the force of tightening the HiPac into the gun.... The manufacturer disagrees....
I try to err on the side of safety....
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: Sat Sep 11, 2010 7:53 pm |
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| kanyon |
| Silver Status Member |
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| rsterne wrote: |
I agree with your numbers 100%.... unless the seal in the front end of the valve fails.... IF that happens suddenly the tube would be pressurized.... Yes, it can leak out around the valve through the sear and hammer slots.... What happens if it can't past the valve fast enough?.... IMO it could result in catastrophic failure.... This is the argument I had with the inventor of the HiPac....
If you assume the seal area is about 1/4" across the end force is about 147 lbs. @ 3000 psi.... The safe working load of the 6-40 screw in shear is about 176 lbs.... Since the transfer port only presses on the side of the valve I don't think it does much to anchor it.... IMO it's a safety issue as the 29 lbs. of safety margin could easily be used up by the force of tightening the HiPac into the gun.... The manufacturer disagrees....
I try to err on the side of safety....
Bob |
Good point..
maybe a releif hole in the tube just incase of seal failer... |
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Career Infinity PCP .22
Webley Patriot .25
Hatsan mod 75 .22
Hatsan mod 99 .177 (Quattro & SAS)
Kral underlever .177
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| Posted: Sun Aug 21, 2016 12:08 pm |
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| Bob La Londe |
| Veteran Member |
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| So, I seem to recall there were some failures with the HiPac adapters and he shut down. What exactly happened? Where can I read some first hand accounts? |
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| Posted: Sun Aug 21, 2016 4:15 pm |
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| AirGunEric |
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| Posted: Mon Aug 22, 2016 9:48 am |
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| Bob La Londe |
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I certainly respect Bob's opinions, but he has never owned one. Has anybody posted a first hand account of a failure? |
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| Posted: Mon Aug 22, 2016 10:39 am |
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| rsterne |
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Is 19 pages of discussion enough?....
http://www.gatewaytoairguns.org/GTA/index.php?topic=97121.0
The primary problem was that the guys who built the gun didn't use the HiPac properly and only used one retaining screw, resulting in the valve ending up in his leg.... However, the HiPac also broke in half where the two parts are joined, through the thin metal below the O-ring groove.... This exposed a weakness which had nothing to do with the discussion above.... I understand they may no longer be available, no idea if that is the case or not....
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 Aug 25, 2016 12:32 pm |
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| Bob La Londe |
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| rsterne wrote: |
Is 19 pages of discussion enough?....
http://www.gatewaytoairguns.org/GTA/index.php?topic=97121.0
The primary problem was that the guys who built the gun didn't use the HiPac properly and only used one retaining screw, resulting in the valve ending up in his leg.... However, the HiPac also broke in half where the two parts are joined, through the thin metal below the O-ring groove.... This exposed a weakness which had nothing to do with the discussion above.... I understand they may no longer be available, no idea if that is the case or not....
Bob |
Thanks, I'll use my proxy to check the G link later. I've been playing with the idea of making something similar for myself and I wanted to know about actual failures. I'm pretty sure they are no-longer available. Both of his website are gone and his Facebook page has been inactive for over a year.
Except for the easy ability to expand them I never understood why he made them the way he did anyway. There is another better way that does not require that nasty join in the middle. |
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