Flyng Dragon PCP Air Tube Failure

[Ribbonstone]

Really do like my FDPCP (xs 60c) and do use it more often than most of the expensive toys.


There are reasons for that.

1.   Shoots 20 “good” shots per fill (about 1500 – 900/850psi).  Energy is between 18 and 19 foot pounds per shot (depending on pellet weight, with heavier earning more than lighter).
2.   Shoots cheap tinned 14.3gr. Crosman pellets well (which are not only chap, but locally available).
3.    Running pretty efficiently and with the home-brew LDC, it is very quiet.
4.   Accuracy has been quite good.  Not “match” good, but much better than the price would lead you to believe.
5.   Been a bit over a year and the Chinese pump still works fine.  Call it 23-24 pump strokes to fill it back up to 1500psi (and 2-3 of them just go to pressurizing the hose before the tube starts filling).

Mods?
1.   Striker adjustment backed out to “zero” in order to run well on a 1500psi fill.
2.   A barrel/tube spacer ahead of the barrel band to keep the barrel from touching the end cap.

3.   LDC
4.   Transfer port on the barrel slightly reduced in order to slow it down/extend 4% shot count to 20 shots.


Tested it today with 3 fills/ 20 shots per fill.



Shot 20 little (about ¼”) circles once each (and missed one).  Not sure what I did for the miss, but the odd shape of the hole indicates a tumble.  I might have managed to load that pellet backwards (honestly, with the scope mounted that low, that kind of thing can happen).

Shot the same circles 5 shots each (4 5-shot groups)
Shot the same circles 20 times each  (2 10-shot groups
So out of 60 shots at 20yards, can consider just 1 miss out of 60 shots.   This will certainly do the job .

Now if the blown-off-tube shows a weakness that can be improved, I’m going to improve it (even to the point of a new, ticker walled/less volume) air tube and keep on shooting.  It is seems to be a one-off happenstance, then will just take care.

Caution and familiarity are opposing forces.  Am comforted that this 1st generation hasn’t had any problems from day one, but if something seems to need improvement, I’ll find a way to improve it.

[avator]

Worse case senario... I think I read back in the thread that there was a body of water nearby. That would be tuff to locate and recover.
Whether it be found or not.... whether the root cause is uncovered and proven or not.... this needs to be a wake up to all of us that it can and DID happen. PLEASE BE CAREFUL WITH ANY AIRGUN !!! The less threads I read like this the better.
And once agian... soooo glad nobody was hurt.

[Tater]

Hi just a thought
What are the odds that the air tube landed on the roof of the house and rolled into a gutter?
Had it happen when I was a kid with a water rocket.
Just an idea

Dave

Oh, was that you? STAY OFF MY LAWN!!!     

Shot the same circles 5 shots each (4 5-shot groups)
Shot the same circles 20 times each  (2 10-shot groups
So out of 60 shots at 20yards, can consider just 1 miss out of 60 shots.   This will certainly do the job .

Excellent shooting there sir! I wouldn't have even guessed they were 5 shot groups unless you pointed it out. Some looked hole in hole.

[Kailua]

Good advice Avator
I am thinking without the tube there is noways to say what happened.  My wondering mind was thinking it could be user error.  We or I will never know.  Being that the FDPCP had no fill pressure gauge could be if filled from a tank user may have miss read the fill pressure.  Even the most experienced may make a careless mistake (talking from personal experience).  Anyways Happy Shooting  JMO

[williesurvive]

http://www.network54.com/Forum/275684/message/1440511558/MWP+Of+Chinese+PCP%27s  This is well worth reading

[ezman604]

Curious WHY the post wasn't made HERE.
Hmmm.....

[SpiralGroove]

Boy ..............,
I'd sure like to hear Bob (rsterne) thoughts regarding the QB Air Cylinder/Tank Block & Valve Integrity, relative to a 1300/1500 PSI Ninja HPA tank set-point.  Yikes ............
Kirk

[Gippeto]

JMO, but if you're going to re-post something...at least take a couple minutes to make it moderately more legible. I typically ignore large, rambling "block" posts..kind of doubt I'm alone in that.

Curious about "which" hydrotest standard is 8/5 MWP. 1.5x and 1.3x design are common with vessels and piping systems while paintball, scuba, scba seem to employ a 5/3 standard.




(C&P was deleted due to not getting permission FIRST. We're not in the habit of copy & paste something but editing it also. It's called plagiarism?)

Might I inquire permission from whom? If by editing, you mean "separating paragraphs"...guilty. Left the content of the post intact, including Tims signature. Certainly wasn't claiming Tims thoughts/words as my own.

Be that as it may, will let it be.

Al

https://www.google.ca/search?q=plagarism&rlz=1C1CHWA_enCA599CA599&oq=plagarism&aqs=chrome..69i57l2j69i59j69i65l3.2302j0j8&sourceid=chrome&es_sm=122&ie=UTF-8#q=plagiarism

[rsterne]

Most of the comments are directed at QBs, and my only comment would be that I agree with Tim @ Mac1 that running a CO2 rifle on HPA without a 1.8K burst disc (which limits the pressure to ~1500 psi) isn't a good idea.... unless you rework the weak points to survive a higher pressure.... The standard hydrotest pressure I am familiar with is 5/3rds of the Maximum Safe Working Pressure.... but pressure reservoirs under 2" diameter and 2' long don't require that, so they are typically designed with a MUCH higher safety margin of 3:1 or greater.... One of the reasons for that is metal fatigue, which on steel becomes a concern if the stress is greater than 50% of the yield strength.... That means that if the safety margin is less than 2:1 of the yield strength, fatigue may eventually bite you.... Hence the 3:1 figure, to avoid that.... If a gun has a 1500 psi MSWP, and a 3:1 safety margin, it should not fail until the pressure exceeds 4500 psi, IMO.... As Tim says, if you make a mistake, you should allow for whatever pressure is in the tank to end up in your gun.... without catastrophic failure....

Bob

[tkerrigan]

I'm wondering if the receiver could have cracked longitudinally allowing the air tube to exit and the receiver threads not to be stripped due to an air cushion while the tube was leaving then snapped shut afterwards.  Cracks can be very hard to see it you aren't specifically looking for them.  I would suggest the owner try to gently pry the receiver threads open in a few different ways and see if a crack shows up.  Something to try.  Regards, Tom 

[Kailua]

Well my offer still stands as when the rifle first came out.  I will throw in a few bucks into a pot to buy and test one of these rifles if any will take the lead.   

[ezman604]

(C&P was deleted due to not getting permission FIRST. We're not in the habit of copy & paste something but editing it also. It's called plagiarism?)

Might I inquire permission from whom? If by editing, you mean "separating paragraphs"...guilty. Left the content of the post intact, including Tims signature. Certainly wasn't claiming Tims thoughts/words as my own.

Be that as it may, will let it be.

Al

https://www.google.ca/search?q=plagarism&rlz=1C1CHWA_enCA599CA599&oq=plagarism&aqs=chrome..69i57l2j69i59j69i65l3.2302j0j8&sourceid=chrome&es_sm=122&ie=UTF-8#q=plagiarism
[/quote]

Hey Al, was not speaking about you.
The post was copied and pasted here before getting the authors permission. Was not talking about you doing the C&P. And I would not edit anything in a C&P, even the grammar errors.
Must keep things like that original. 

[ronbeaux]

Just a thought.

We had a 1/2" thick 20" pipeline rupture and fling sections of pipe over 200yrds in three directions that was transporting methane. It was idle at the time and only had 600 psi contained. It was a 2200 psi rated line. After gathering and analyzing the pieces we found , it was determined that a corrosion pit that reached 70% of the thickness was the intitial cause of failure. Since the pipe contained a gas the rupture was many times more violent than one containing liquid. A Chevron pattern pointed to the intial point of failure.


Sooo. What if the gun had moisture in the tube and sat long enough in one place to start the corrosion and when it failed it failed so dramatically that the section of threads were not "pulled free" but instead simply deformed enough to loose contact.

And looking for one piece is why you are not finding multiple pieces instead? We found 13 individual pieces.

Very interesting 7 pages of info here. Just haven't seen this line of thought.

The pieces we found looked like torn paper and it was 1/2" steel.

[Sfttailrdr46]

  My apologies for the copy and paste of the authors post without his permission I was just attempting to provide further safety information . Unfortunately I engaged my fingers before my brain

[nervoustrigger]

Don, I don't see the problem at all.  It is an internet posting in the public domain and you made no claim that it was your original material.

[Tater]

Interesting thought there ronbeaux. The gun was unused for quite a while.

[Bill G]

Has anyone thought of doing a magniflux on the receiver? The pics that we have seen don't have enough resolution to be nearly as good as in person and in person, a fine crack in the aluminum could be very hard to detect.  That same, nearly undetectable crack, could also flex enough to allow escape of components with out much damage to threads.  Its a thought although it doesn't seem likely since the gun had no real service. Anyway, at this point, any avenue of discovery is worth while especially since parts are missing.  I would imagine, from the view point of the manufacturer, I'd want to have that test done.

Bill 

[SpiralGroove]

Thanks Bob for the clarification ,
Even though he briefly mentioned the 1.8K burst disc in his post, I missed that "it" was the Trump Card for all his (TimmyMac1) QB concerns?  His tone was pretty foreboding
Whew .................. I was starting to have Other thoughts
Kirk

[GLPalinkas]

Just a thought.

We had a 1/2" thick 20" pipeline rupture and fling sections of pipe over 200yrds in three directions that was transporting methane. It was idle at the time and only had 600 psi contained. It was a 2200 psi rated line. After gathering and analyzing the pieces we found , it was determined that a corrosion pit that reached 70% of the thickness was the intitial cause of failure. Since the pipe contained a gas the rupture was many times more violent than one containing liquid. A Chevron pattern pointed to the intial point of failure.


Sooo. What if the gun had moisture in the tube and sat long enough in one place to start the corrosion and when it failed it failed so dramatically that the section of threads were not "pulled free" but instead simply deformed enough to loose contact.

And looking for one piece is why you are not finding multiple pieces instead? We found 13 individual pieces.

Very interesting 7 pages of info here. Just haven't seen this line of thought.

The pieces we found looked like torn paper and it was 1/2" steel.

Just thinking out loud here, no real experience in this type of work, but wouldn't the fact that it was in a gun case and the hole in the case shows that a single point of exit was made indicate your idea that it fragmented not logical. ps without searching all of this thread, I may have seen the photo of the gun case from the yellow link.

[Poorman Plinker]

Ronbeaux may have hit the nail on the head. Nothing like personal experience to provide useful information that can be generalized to another situation. My experience with Crosman parts (A US company that also has some parts made overseas) is that not all parts have the same quality or condition. For example Gas tubes of the same part number come with different color and quality of craftmanship. What is to say that one part could have a flaw that 100,000 parts would not share. EG: A small pinhole rust spot that could grow over time.

And this is really off topic but has filled a lot of the discussion:
As for the discussion on plagerism... might want to include a discussion on liable (falsely accusing someone of something that causes damage to their reputation). As stated by the accused party he did give the source of the quote and is not plagerism. Is it a violation of copyright? Probably not, even though electronic publication is protected by copyright a violation is determined by quantity of material copied and the intent of the copying and the damage to the author. Peace is the answer!