This Is What Can Happen.....

[rsterne]

Call me naïve, but I don't like pointing the finger at people based on nothing but guesses, and even accusing them of lying.... Continuing in that direction, instead of sticking to the facts we are given, even if they don't make a lot of sense to us, will likely end up with this thread being locked.... If anyone has any proof that contradicts the story we have been told, then please present it.... Otherwise, let's just investigate the facts as they are presented, using the Physics we know, and reasonable suggestions where things don't make sense.... Is anyone actually disputing these facts, and if so, what are you basing that on?....

1. The (single) valve screw sheared, resulting in the valve ending up in his leg, after exiting the rear of the tube.... The video supports this....
2. The HiPac broke through the thin section below the O-ring groove, and ended up imbedded in the ceiling.... The video supports this....
3. Unless you think they are lying, their testimony is that the gun ended up on the floor, near the source of the explosion....

You can, as I did, propose that the gun flew out of his hand, collided with something, and that impact broke the HiPac, but I asked them that, and they deny it.... Were you there?.... Do you have proof they are lying?.... If not, then I think we should accept those facts and try and figure out what happened and how to avoid it in the future.... The valve seems simple enough, use three screws.... Anyone have anything to say about the HiPac?.... If you own one, are you going to measure the thickness at the O-ring groove?....

Bob

[Doug Wall]

All this speculation about the valve coming out the front of the tube is BS. Although he claims that the valve went in face first, I doubt that he was in any shape to watch the surgery to see which end was which. If you look at the video, as he was under EMT care, he mentions the valve "sticking out of the back" of his leg. The video shows a bulge under the skin on the back of the leg. The bulge looks a bit pointy, like there is a valve stem under the skin, just waiting to come out. Unless someone can prove otherwise, I'm convinced that the valve retention screw sheared while he was holding the butt of the gun against his thigh, and the valve blew right into his leg.
Seems like a good nomination for a Darwin Award!

[Gerard]

Of course I wasn't there. But I can think. And my understanding of basic physics tells me that no 'shock wave' or 'steel quake' possible within the system in question could possibly explain an EXACTLY simultaneous separation of the valve retention bolt and the HiPAC at its thinnest point. Further, my HiPAC has no O-ring groove at the point of entry into the Crosman tube, so if theirs failed at that point then this O-ring groove is an introduced feature. Mine screws into the Crosman tube with plain threads, a fact thoroughly established by countless HiPAC owners and by Alex, and anyone looking at one installed can see that there is a small gap between the OD and the Crosman main tube in any installed HiPAC. It's not a sealed joint. If the HiPAC (or 'Hipacs') in question broke at an O-ring groove in that location, they cut that O-ring groove, and weakened the wall by overly thinning it in an already thin area, probably the thinnest on the whole product. I can see why they'd do that given the fact they hacked off the business end which is supposed to seal against the valve and instead sealed the HiPAC to the main tube, because they'd need an O-ring in that location to form a seal. But carving a groove for an O-ring in a thin steel tube not designed to be thinned further in that location is foolhardy, putting it politely.

That said, there's no engineering principle nor law of physics which seems likely to explain how that thinnest part of the tube and the one retaining bolt could possibly be IDENTICAL in mechanical weakness such that they would just happen to fail at the same precise instant, driving a valve through his leg and the HiPAC into the ceiling/wall of another room. If anyone knows of such a law or principle which contradicts this statement I should be most happy to entertain it and perhaps eat my words. But as I understand this universe, the weakest point in a pressurized system fails and the release of said pressure obviates any further mechanical failure in the same system, regardless of weakness, as the entire pressure has been instantly dumped. A mechanically unsound .50BMG does not explode the barrel AND fire the bolt back into the shooter's face. it's one or the other. A burst hydraulic line doesn't spray fluid all over a machine AND simultaneously eject a loosely fitted piston out of its sleeve. The pressure just isn't there to do the second job.

Looking at the shakey, distant video footage of that embedded HiPAC as the only provided evidence (their testimony being in question, in my opinion, due to inconsistencies and what seems a deliberate retention of verbiage - guy's long on blah blah blah about the 'community' but very short on actual facts and close-up pictures of the embedded HiPAC) I am left with little alternative but to conclude that either it broke off as an after-effect of the initial acceleration of the gun out of his hand then an impact with some intervening hard surface (the vise?) then a flight to the point of impact, or that they inserted it into the ceiling manually. If the latter, shame on them. If it's merely a misinterpretation of the chain of events, their own intellectual failure to properly interpret the chain of events Bob spelled out earlier regarding the gun having impacted something and broken the thinnest point on the HiPAC, then that's perfectly understandable, but they ought to cease blaming the product as they again are doing. A drastic user modification such as cutting an O-ring groove is NOT something for which Alex nor his product ought to be blamed!

[rsterne]

Gerard, you must have a different HiPac than anyone else.... The O-ring groove is outboard of the shoulder, and seals the two parts of the HiPac together.... That is exactly where the HiPac broke.... Perhaps you should examine a stock HiPac before making such nonsensical statements in the future.... When you add an Extension to the HiPac, that is where it is installed, and carries it's own O-ring, so then you have two....



Bob

[BigTinBoat]

... If anyone has any proof that contradicts the story we have been told, then please present it.... Otherwise, let's just investigate the facts as they are presented, using the Physics we know, and reasonable suggestions where things don't make sense.... Is anyone actually disputing these facts, and if so, what are you basing that on?....

Well the angle that the HiPac entered the ceiling disputes the fact that it "sheared" off and went directly into the ceiling........unless he was sitting on a chair that was one some type of platform attached to the wall at least 1/2 way up off the floor.

Look at the below sequence of pics taken from the video.
Notice the "wall" in the first photo. This is not the wall you see when you see the HiPac in the ceiling
Notice where table is, notice where victim is laying with Medic's and notice where HiPac is. NO way that Hipac went "straight" into the ceiling from where the victim was.

[rsterne]

BigTinBoat.... I have an alternate theory for the angle of the HiPac.... It entered the ceiling at a shallow angle, after flying across the room, and impacted a joist.... If the part of the HiPac sticking out of the ceiling is heavier than the part inside, then it could easily end up sitting at a different angle than it entered at, without falling out of the ceiling.... Or alternately, the other way around, entered steeply and ended up on a shallow angle.... My point is that the angle it ended up on is not PROOF of it's trajectory.... only that it left the gun....

Unless you are saying that they staged the whole event, broke the HiPac off the gun and rammed it into the ceiling, and are lying about everything.... Do you really want to claim that on a public forum?.... I certainly don't....

Bob

[Gerard]

So Bob, you're saying this was not the failure point?



This is where I've seen it pointed to in a couple of forums. Between the fine Crosman threads and the shoulder. Approximately even with the end of the Crosman tube. Where there is no O-ring groove. It's a threaded fit, just as is the Crosman CO2 cap in a stock setup. No seal wanted or needed, nor provided. As it happens I slapped a skinny O-ring over that spot on mine to even out the appearance of it, filling in the gap when I went to paint mine after everything was sealed and reliably working. But there's no seal there.

BigTinBoat; thanks for the screenshots, which only go further to confirm the HiPAC must have deflected off something in that working area to rebound into that far corner.

[rsterne]

Nope, it failed the other side of the shoulder.... You can see the shoulder, albeit poorly, in some of the first video.... It is duller than the rest of the tube, and a slightly different colour.... You don't notice it easily unless you are looking for it, because it is the same OD as the tube, designed that way for appearance.... You can CLEARLY see where the HiPac failed in the cover photo for the 2nd video a couple of pages back, in post #173.... The shoulder couldn't be more visible, still attached to the Crosman tube, than in that photo....

It is entirely possible that the HiPac deflected off something before imbedding into the ceiling.... However, that does NOT mean it was still attached to the gun when it hit whatever it deflected off of.... Their testimony is that it was NOT.... Can you prove otherwise?....

Bob

[BigTinBoat]

BigTinBoat.... I have an alternate theory for the angle of the HiPac.... It entered the ceiling at a shallow angle, after flying across the room, and impacted a joist.... If the part of the HiPac sticking out of the ceiling is heavier than the part inside, then it could easily end up sitting at a different angle than it entered at, without falling out of the ceiling.... Or alternately, the other way around, entered steeply and ended up on a shallow angle.... My point is that the angle it ended up on is not PROOF of it's trajectory.... only that it left the gun....

Unless you are saying that they staged the whole event, broke the HiPac off the gun and rammed it into the ceiling, and are lying about everything.... Do you really want to claim that on a public forum?.... I certainly don't....

Bob

Bob -  I NEVER made claim to anyone staging anything. They just have no idea what happened. I will say, are not very good "investigators".

Remember - they were "knocked back by the explosion"

[rsterne]

Not very good investigators.... I agree....

Knocked back by the explosion.... I would think so, that's a lot of energy being released by the expanding air.... Did you see what it did to the stock on the  FD-PCP, and the case it was in?.... He probably dropped the gun, too (I sure would have!), which would explain it ending up on the floor "at his feet".... That is why I specifically asked if the gun (not the HiPac) flew across the room, or impacted anything.... They said no.... We weren't there, so I feel we have no reason to not investigate it from the assumption they are telling the truth....

Bob

[Gerard]

Without the guy who did the work being a LOT more forthcoming with information, offering real dialogue not just snippets and half-answers and no supporting documentation (clear, close-up photos of the damaged parts), all any of us has is conjecture and the power of thought. So asking me repeatedly for proof is just spinning your wheels really. Of course I don't. Of course I wasn't there.

So it broke on the other side. That's even more strange. How? There could be no significant stress there after the valve retention bolt had sheared, sending the valve into his leg. And I think anyone with a grain of sense understands that there's no potential for the valve having gone forward, out the front of the gun's tube, as the mechanic involved has stated. His ignorance in that regard alone brings his entire testimony into question, as he plainly has no understanding of basic physics. A valve can not fly AGAINST the pressure source. Miracles like that just don't happen. Unless of course he hid a higher pressure tube behind the valve somewhere... but no, that's just silly. So a HiPAC supposedly broke in an area where there are both inside and outside threads containing the pressure, providing mechanical stiffness?

So I downloaded the video, and am playing through parts frame by frame. One thing which stands out is that the parts embedded in the ceiling are poking vertically into the ceiling, at an angle slightly back towards the work station. It looks like it deflected off the wall before stabbing into the ceiling drywall. The work station is just below and a couple of feet back from the wall. So it the gun was pointed muzzle towards the wall at an upward angle, which it would be since the valve went at a downward, backward angle through his leg while seated at that work station, it makes sense that it would have bounced off the wall and/or the vise before stabbing the ceiling.

I'll add another theory to the mix here. What if the guy was, as has been suggested a few times in this thread, actually trying to unscrew the one retaining bolt from the valve? Had a brain fart, forgot that 2,000psi was being restrained by only that one bolt, and tried to unscrew it. Hey, most of us will forget stuff while talking to a camera... or to a phone for that matter, hence the laws against doing so while in control of a vehicle. For whatever reason, if he were unscrewing that bolt it would not be easy. He's not presented us with a sheared-off bolt head, so either it's lost in his house or he's decided not to show it. What if it didn't shear? What if he managed to partially unscrew it, even most of the way out? If that were the case, and given that doing so would be very difficult owing to the enormous pressure pushing the valve backwards in the tube, wouldn't he have to push very, very hard on the gun to support it while pushing in very hard with a tool to unscrew that bolt? I'd venture to guess he might even have been pushing the gun, actually the HiPAC itself, against his bench vise. With that sort of angular pressure, isn't it probable that the HiPAC could have split through its weakest point, under a stress which it was never intended to bear? And following that... as the HiPAC, assisted by 2,000psi of air pressure, parted with itself and the gun and headed towards the ceiling... the tool he was using to push into the bolt lurched a bit, exerting extra force on that almost-loosened bolt, which then broke free from its threads and allowed the valve to shoot backwards?

While still very difficult to imagine these two events happening at exactly the same instant, it seems somewhat more plausible. The peak force applied would have been at the instant of greatest exertion by the mechanic as he pushed very hard towards the bottom of the tube, to prevent slippage of the tool while turning it, and that peak force would also manifest against the HiPAC if he was bracing it against something solid as I describe.

And then in hindsight, wouldn't it be perfectly understandable human nature to pretend the lateral force needed to perform such an obviously foolish operation was not part of the equation? Which of us would easily admit to doing something THAT stupid? If I had been involved, you can be dang sure the video would never get uploaded in the first place. Unless I somehow failed to understand (as his friend might have failed to understand) the depth of foolishness involved in attempting to un-secure the valve while under pressure... And I take it the friend was the one who uploaded the video, not the mechanic himself, is that correct?

And lastly; the gun being on the floor at their feet, their close proximity to the gun when it went off and their having been blown backward... all that seems to further point to the idea that a tremendous physical effort was being undertaken at the moment of the explosion, that a screwdriver was being pushed into the bottom of the tube while bracing the HiPAC against something, the back of the tube pressing against his upper thigh. The gun would naturally go down, towards the legs of the bench.

[BigTinBoat]

. We weren't there, so I feel we have no reason to not investigate it from the assumption they are telling the truth....

Bob

I generally conduct "my" investigations with an open mind. Weighing the "facts", possibilities and probabilities. If we were to investigate this with "the assumption they are telling the truth" wouldn't we still be trying to figure out how the valve went into his leg "face" first?

[BigTinBoat]

One thing which stands out is that the parts embedded in the ceiling are poking vertically into the ceiling, at an angle slightly back towards the work station. It looks like it deflected off the wall before stabbing into the ceiling drywall. The work station is just below and a couple of feet back from the wall.

Gerald. The Hipac is in the ceiling nearer to the wall that is "opposite" where the work station is. That Hipac had to fly completely across the room. Look at my sequence of pics. The Hipac is nearer a wall with green cloth, the "workstation wall has a window in it, with brown shades. It across the room, closer to the "kitchen", where he winds up "on the floor". That's why I say "NO WAY" that HiPac went "straight" into the ceiling.

[rsterne]

Gerard, I am glad to see that you have tempered your position somewhat.... You had an experience with a HiPac that all logic says should never have taken place.... I'm sure that it didn't (doesn't) feel very good when people say it didn't happen the way you said it did.... It would be nice to give these guys the same break, and assume that they didn't just make it all up, or have some ulterior motive.... I do agree that a significant side force on the HiPac, during an attempt to remove the stock (ie the front trigger screw), which would have been under significant force, if the (single) valve screw was already compromised (as I proposed much earlier).... could have caused the HiPac to fail.... So could falling on it, if the area under the O-ring is too highly stressed, because (for instance) it is thinner than spec.... The area where the O-ring groove is, is subject to hoop stress from the internal pressure.... and also longitudinal stress from the end load (664 lbs. at 2200 psi)....

In terms of the direction the valve was going when it ended up in his leg, I just chalk that up to emotion, and being convinced at the time (of the first video) the valve "must" have come out the front of the gun.... Since the rear of the HiPac is still screwed into the Crosman tube (in fact glued in place, they admit it can't be removed), we all know (including the guys who said, mistakenly, in the first video it went out the front) that it went out the back, into his thigh.... Harping on a simple mistake, since corrected, has no point.... There is a big difference between lying and making a mistake, IMO....

Bob

[Gerard]

Gerard. The Hipac is in the ceiling nearer to the wall that is "opposite" where the work station is. That Hipac had to fly completely across the room. Look at my sequence of pics. The Hipac is nearer a wall with green cloth, the "workstation wall has a window in it, with brown shades. It across the room, closer to the "kitchen", where he winds up "on the floor". That's why I say "NO WAY" that HiPac went "straight" into the ceiling.

That's what I'd been thinking too, that the wooden blind and the green sheet were indicative of different areas of the house. Largely owing to the fact that several contributors to this thread have indicated as much. But looking through the video, I see that there are food items and a microwave oven on the table where they choose to show the bloody valve on a paper towel. The table surface is different from that of the work bench. There's no vise, no gun rest. Look at these two screenshots, one of the place they're showing the bloodied valve, the other a few seconds later showing the distant green sheeted window, where there seem to be both a vise and a gun rest in place.




Apples, a bag of something like tea bags, a can of pop, all manner of food-related items. Not on the workbench in the earlier video, are they?

[BigTinBoat]

... There is a big difference between lying and making a mistake, IMO....

Bob

I agree 100%....and I think he is mistaken when he say  "it was the HiPacs that failed first and the massive rapid change in air hit the air valve like a hammer and then it let go", don't you?

[BigTinBoat]

The table surface is different from that of the work bench. There's no vise, no gun rest. Look at these two screenshots, one of the place they're showing the bloodied valve, the other a few seconds later showing the distant green sheeted window, where there seem to be both a vise and a gun rest in place.




Apples, a bag of something like tea bags, a can of pop, all manner of food-related items. Not on the workbench in the earlier video, are they?

I agree that the table it NOT the workbench, but the "window blind" his is working on is not on that wall with green sheet (unless they decided to put the sheet up to cover the blind between the explosion and the medics getting there. Look at the 3:13 minute of 1st video. There is no "window" between that "light" in front of the green sheet and the door behind the medic. My thought is that the "workbench" is on the opposite wall. If sitting at that kitchen table it would be to your "right", the wall he is lying next to when the medics are tending to him.

Basically the far left of this pic

[rsterne]

This part of the statement....

massive rapid change in air hit the air valve like a hammer

doesn't make a lot of sense, but I can't disprove it.... It is possible that a shockwave from the first part that failed triggered the second one to fail.... and that shockwave could have been transmitted through air or steel (my "steel-quake" idea).... It is also possible that the gun "rang like a bell" vibrating violently in several directions, and a harmonic did in the second part.... I suppose it's even possible, if the valve failed first, that the sudden lack of hoop stress in the O-ring groove in the HiPac caused it to reverse or flatten it's curvature and fracture before the air pressure dropped low enough to not blow it off the end of the gun.... The point I have been trying to get across is that it is POSSIBLE for both parts to have failed at so close to the same instant in time that the air pressure had not dropped to the point it could not occur.... and that is the story we have to work on....

While I understand the "sleuthing" of trying to dissect the video, the layout of the building and furniture, etc.etc.... I still think it only valid if you don't believe the basic statement that the HiPac departed the gun before rocketing off to end in the ceiling.... If it departed the gun during the event, and not as a result of a secondary collision (which they say didn't occur), then its trajectory after the fact doesn't matter....

Bob

[Gerard]

Seems likely to me that for whatever reason (the blind damaged by the HiPAC hitting it, for example) they hung the green sheet over the blinded window behind the work station after the event, before filming the homecoming portion. And it seems likely that the force exerted into the side of the gun, somewhere near the middle, would easily account for the HiPAC breaking at its weakest point. No shock waves required. Steel vibrates when hit with sudden force. Like a tuning fork. It doesn't just break in half. If the pressure were extreme enough to cause the separation, wouldn't we see some 'peeling' back of the steel somewhere? Failed steel air cylinders usually show that sort of damage.

Nope, I'm sticking with the new theory of bending stress from trying to undo the valve retaining bolt, or the forearm bolt if the valve bolt was already sheared and the forearm bolt was the last remaining restraint which does seem to make more sense. 'Cause hey, no one's THAT stupid to undo the valve bolt, right? He just didn't (doesn't?) understand that the forearm retention bolt could have been the only thing holding the valve in place at the time (and now?).

[chekbone]

My bad.