Leshiy 2 explodes

I've just examined 3 buttstock extensions AKA upper reservoir tubes from my Leshiys.

1 long extension, came from a complete gun from Edgun West from one of the first runs: conical bottom of the tube, some machining marks on the bottom, but smooth transition from walls. Hard to tell but there could be a small radius there.
1 shorter extension, came from Edgun Spain as a part of complete EAR rear assembly around 1 year ago: conical bottom, also a smooth transition.
1 shorter extension, came recently from Edgun West as a separate part: flat bottom, sharp corner. Also no anodizing on the bottom of the tube.

So yes, there are clearly at least 2 variations of the shorter buttstock extension out there.

poopty pictures from my phone, but you get the idea.

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I don't have any skin in this debate, but I would not be pleased if that was the interior machining/finish on almost all of those tubes. I'd expect that kind of finish from a crosman. Eeesh
 
Are those of you familiar with the many PCPs out there that use aluminum pressure vessels/tubes is there a history of them failing and if so were there conclusions made that resulted in design changes to make them safe? Surely Leshiy 2 is not the first example of this type of failure? Assuming this is a design error, have other manufacturers made the same mistake in the past? I sure hope there are efforts to add some safety margins to this part. Even if the officially gun is safe, corrective action on Edgun’s part certainly could make it safer? Perception should not be ignored. I know in my case I have limited my L2 to 250 BAR and even a little more careful how I handle it. No butt bashing etc…
 
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I’m still in the camp some external force was in play here coupled with the design. Let’s face it, the tube in Marko’s testing did not fail at containing a very high test pressure. Design flaw, yes from a safety factor and a lifespan standpoint. Very concerned for those who own these? Sure I am. But to be honest, looking at an AEA (or similar), brings up the same concerns.

Dave
 
I know in my case I have limited my L2 to 250 BAR and even a little more careful how I handle it. No butt bashing etc…
Personally, I will not be using that tube with the flat bottom and sharp corner, period. Now that we have an idea what difference it makes. I'll take my chances with the other 2 with the same precautions.
 
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@MJP If you would please, take a few extra minutes to also completely disassemble the plenum/regulator chamber to take all the dimensions of that to input them into your CAD program for determining the stress there. I ask this because if there's anything that needs to be addressed there, it is best to know now before a failure occurring with that part as well. Thank you for your dedication to the safety of the people of the airgun community.
 
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1 long extension, came from a complete gun from Edgun West from one of the first runs: conical bottom of the tube, some machining marks on the bottom, but smooth transition from walls. Hard to tell but there could be a small radius there.
1 shorter extension, came from Edgun Spain as a part of complete EAR rear assembly around 1 year ago: conical bottom, also a smooth transition.
1 shorter extension, came recently from Edgun West as a separate part: flat bottom, sharp corner. Also no anodizing on the bottom of the tube.
According to the simulations done by Marko it seems that conical bottom with smooth transition is good enough assuming the right alu was used. But we don't know which air tube is which without disassembling. What we know from your post is that the EDgun machinists do not pay much attention to that detail hence the differences.
 
Another thing which comes to my mind - what if some tubes are manufactured like that:

Screenshot_2023-04-29-17-21-34-020_com.google.android.apps.photos~2.jpg

Flat bottom. A little deeper.
 
@MJP If you would please, take a few extra minutes to also completely disassemble the plenum/regulator chamber to take all the dimensions of that to input them into your CAD program for determining the stress there. I ask this because if there's anything that needs to be addressed there, it is best to know now before a failure occurring with that part as well. Thank you for your dedication to the safety of the people of the airgun community.
I will see what i can do. But this is taking alot of time to reverse engineer the design for simulation.
The gun at hand wont have any other pressure related parts left original than the valve block and buttock.

I'm designing a completely new modular cylinder with threaded end plugs and a crmo tube.

Marko
 
Are those of you familiar with the many PCPs out there that use aluminum pressure vessels/tubes is there a history of them failing and if so were there conclusions made that resulted in design changes to make them safe? Surely Leshiy 2 is not the first example of this type of failure? Assuming this is a design error, have other manufacturers made the same mistake in the past? I sure hope there are efforts to add some safety margins to this part. Even if the officially gun is safe, corrective action on Edgun’s part certainly could make it safer? Perception should not be ignored. I know in my case I have limited my L2 to 250 BAR and even a little more careful how I handle it. No butt bashing etc…
Most manufacturers use tubing with threaded ends, it's the most common type. And easies to manufacture.
Making a tubing from solid is kind of stupid.
Just my point of view.

Marko
 
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I will see what i can do. But this is taking alot of time to reverse engineer the design for simulation.
The gun at hand wont have any other pressure related parts left original than the valve block and buttock.

I'm designing a completely new modular cylinder with threaded end plugs and a crmo tube.

Marko
I understand where you are coming from with regards to doing the reverse engineering the plenum/regulator area for only a simulation.

Because you already have the dimensions for the rear air cylinder, manufacturing a safe and potentially larger air reservoir and offering them for sale is a great idea and would be welcomed.
 
I don't care for the factory LOP on my REPR L2 so I ordered what was supposed to be a shorter air tube late 2022.

Not sure where the confusion was but it was the same length as my REPR air tube
I never requested a return, never installed it.

It has a conical bottom. Maybe a slight radius at transition. The lighter colored area just past 12:00 has no anodizing & transfers slightly up the tube. At least to my untrained eye. See picture #2.

20230429_101442.jpg

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I have thought about ordering one of the two compact air tubes from Spain but couldn't decide on what length to get. Needless to say I will probably hold off.

My L2 was purchased new late summer 2022. If it's helpful I can remove the factory air tube that came with it & take the same picture.