Leshiy 2 explodes

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sb327 said:
I’m not saying 2.5sf is right, it’s just midway of what the gentleman in the video said…2 to 3

Dave
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2 to 2.5 for yield, 3 to 3.5 for burst for people that build their own is certainly acceptable, but industry standard for any pressure vessel is 3.5 for burst.

Plus as the gentleman in the video mentions these HPA tubes are not vessels that have testing measures imposed on them, ever. They should be built to higher standards to last multiple life times without deformation, also to be able to withstand drops/dings being their use case.
 
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For example, this is a my cheap old marauder's tube specs, as you see its designed with a SF of 3.5, and a fill pressure of 3k psi. Taking the SF to 2.5 gives 4200 psi, which you don't see marauder owners going around doing, or announcing publicly that they do, nor would anyone recommend it. I personally don't mind overfilling some but..I respect HPA, and so should anyone buying OR selling these guns.
 
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if there is a chance that all the edguns this model or all models, I'm not an expert, have a compromised metal thickness, which we believe one has exploded, he should put a statement out warning others to not use them until he can work through this. Wouldn't that be the competent thing to do? Instead I see a guy acting like Putin with his chest puffed out on a beach. Remember Putin on his horse, someone said he was a child molester at the time. That whistleblower is dead now I believe. Where are these guns made?
 
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sb327 said:
What material does the marauder tube use?

Dave
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My tube is 2024-t3 aluminum custom made before JSAR did their runs. Although marauder tubes use DOM steel which is closer to 85k tensile strength IIRC.

I don't believe there is any certainty in what material the L2 uses...but at the 2k+ price point, I would want nearly any storage vessels within the gun to be made of titanium, the cost of the material isn't that much, but its superiority gap to aluminum is almost doubled in tensile strength.


Deltaman said:
if there is a chance that all the edguns this model or all models, I'm not an expert, have a compromised metal thickness, which we believe one has exploded, he should put a statement out warning others to not use them until he can work through this. Wouldn't that be the competent thing to do? Instead I see a guy acting like Putin with his chest puffed out on a beach. Remember Putin on his horse, someone said he was a child molester at the time. That whistleblower is dead now I believe. Where are these guns made?
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Too early for a statement, would need definitive proof of how this failure (if true) resulted...
 
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Stubbers said:
My tube is 2024-t3 aluminum custom made before JSAR did their runs. Although marauder tubes use DOM steel which is closer to 85k tensile strength IIRC.

I don't believe there is any certainty in what material the L2 uses...but at the 2k+ price point, I would want nearly any storage vessels within the gun to be made of titanium, the cost of the material isn't that much, but its superiority gap to aluminum is almost doubled in tensile strength.




Too early for a statement, would need definitive proof of how this failure (if true) resulted...
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I was simply wondering exactly what the marauder used for the FACTORY material because you referenced them for an example of an ‘industry standard’. I’m not sure if I’ve seen any standards written for airguns nor have I seen them marked. (There may be an example I’m unaware of) I can only assume the manufacturer (whatever country) follows their own design standards. I am aware that bottle manufacturers are generally labeled with the standards they conform to, for example CE and DOT.

Dave
 
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sb327 said:
I was simply wondering exactly what the marauder used for the FACTORY material because you referenced them for an example of an ‘industry standard’. I’m not sure if I’ve seen any standards written for airguns nor have I seen them marked. (There may be an example I’m unaware of) I can only assume the manufacturer (whatever country) follows their own design standards. I am aware that bottle manufacturers are generally labeled with the standards they conform to, for example CE and DOT.

Dave
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The factory material meets or exceeds ASME standards for pressure vessels.

Industry standard I stated was an American Society of Mechanical Engineers standard for pressure vessel. It's a factor any engineer *should* include in their design. I don't see anywhere it is acceptable to go down to 2.5 for a FoS but again, its quite the grey / unregulated area and I conform personally to pressure vessel standard.

info.thinkcei.com

ASME Section VIII BPV Code & the Pressure Vessel Safety Factor

ASME Section VIII standards regulate design safety. Understand how material properties impact pressure vessel allowable Stress, materials and safety factor
info.thinkcei.com info.thinkcei.com
 
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Stubbers said:
The factory material meets or exceeds ASME standards for pressure vessels.

Industry standard I stated was an American Society of Mechanical Engineers standard for pressure vessel. It's a factor any engineer *should* include in their design. I don't see anywhere it is acceptable to go down to 2.5 for a FoS but again, its quite the grey / unregulated area and I conform personally to pressure vessel standard.

info.thinkcei.com

ASME Section VIII BPV Code & the Pressure Vessel Safety Factor

ASME Section VIII standards regulate design safety. Understand how material properties impact pressure vessel allowable Stress, materials and safety factor
info.thinkcei.com info.thinkcei.com
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How do you know it (the marauder tube) meets those standards?

Again, I never said 2.5 was good, only the gentleman in the video….



Dave
 
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The safety factor discussion is interesting but I don't think it helps explain a burst air chamber. If it is designed to yield at twice the pressure it should see in use, then it won't fail without something else bad happening. If it is designed to fail at 110% of working pressure, it will not yield without something else happening. I think the question is what the "something else" is. Could be a hidden flaw in the material, a manufacturing glitch, or something the user did to the gun. Or multiple improbable things which all added up to result in stress above the limit for the material.
 
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sb327 said:
How do you know it (the marauder tube) meets those standards?

Again, I never said 2.5 was good, only the gentleman in the video….



Dave
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The stock / factory marauder tube is likely made from common DOM steel with 85,000 psi tensile strength, while no one but Crosman knows the exact grade, it certainly isn't going to be of weaker tensile strength than any aluminum counterpart.

The reason I included a marauder tube as an example is because of my experience with them and having one on hand, their maximum fill pressure is written on their documentation and the rifle itself as 3,000 psi and the air tube is designed to withstand more than that at a FoS of 3.5 as any pressure vessel should be designed. Both factory and aftermarket tubes were tested to failure by lloyd-ss iirc and made it slightly beyond what barlow's formula calculated as burst pressure prior to failure. Also, to that note, what I believe failed was an area of the tube around the valve retainer screws, allowing the valve to push back and the tube to vent...adding a 4th screw would make them likely even more capable..although I prefer the factory mode of failure. Having your mode of failure designed into the rifle is most ideal.
 
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JimD said:
The safety factor discussion is interesting but I don't think it helps explain a burst air chamber. If it is designed to yield at twice the pressure it should see in use, then it won't fail without something else bad happening. If it is designed to fail at 110% of working pressure, it will not yield without something else happening. I think the question is what the "something else" is. Could be a hidden flaw in the material, a manufacturing glitch, or something the user did to the gun. Or multiple improbable things which all added up to result in stress above the limit for the material.
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There is a good reason you adhere to general guidelines, especially safety factors for pressure vessels. Who wants to have their air rifle compromised by a simple .005" deep scratch or gouge, or as you say a flaw/defect in the material. My custom air tube had a minor defect that concerned my machinist when I sent it to him, I simply asked if that area of the tube could be set into an area of the tube that only sees atmospheric pressure (ie: between the regulator or hammer area) and he measured it out and determined that it could be, so we proceeded, otherwise that tube would of been scrapped.
 
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sb327 said:
I’ll quit…I’m only trolling along to point out that a LOT of assumptions have been made (even by the YouTube engineer with a weak battery in his caliper).

Dave
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Lol he isnt just some random youtube engineer.. he have actually build worlds most powerful airgun, only person that have been confirmed to exceed Mr Bob Sternes lofty goals etc.. his track record is long and notable..
 
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SlugmasterABC said:
Lol he isnt just some random youtube engineer.. he have actually build worlds most powerful airgun, only person that have been confirmed to exceed Mr Bob Sternes lofty goals etc.. his track record is long and notable..
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There is no disrespect intended. Even he will have to make assumptions.

The biggest question will always be what led up to the event.

Dave
 
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SlugmasterABC said:
Lol he isnt just some random youtube engineer.. he have actually build worlds most powerful airgun, only person that have been confirmed to exceed Mr Bob Sternes lofty goals etc.. his track record is long and notable..
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Exceeding Bob Sterns lofty goal is easy because his calculation assumes only 50% of the barrel volume is used before the valve no longer produces usable air to the further increase velocity of the projectile, but with SHORTER barrels this is far from the truth....its a awful calculation that I personally vastly improved upon that takes barrel length into consideration among other factors.

Marko is a smart guy.
 
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sb327 said:
There is no disrespect intended. Even he will have to make assumptions.

The biggest question will always be what led up to the event.

Dave
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Well thats good since he is honest guy and he has zero motivation to do anything else than hand out truth. I personally dont trust manufacturer in such case. Im sure he will post followings in near future since he have alrdy posted some more results in our own national forum.
 
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