AIRGUNNER PUBLIC SAFETY ANNOUNCEMENT: DO NOT USE THIS PRODUCT FROM PCP TUNES

[UpNorthAirGunner]

AIRGUNNER PUBLIC SAFETY ANNOUNCEMENT: DO NOT USE THIS PRODUCT FROM PCP TUNES - Airforce Texan Regulator with Dual Gauge V1!!!! I just got off the phone with a trusted airgunner who informed me there has been a catastrophic failure of one of these devices. I just received the photos and it is scary.

You may have seen me recently test this regulator on a video and on social media posts. This kind of failure is a zero tolerance issue in my book. If you have one of these - TAKE IT OFF. If you just ordered one - CANCEL YOUR ORDER. If you have one - DO NOT INSTALL IT!

Thank GOD no one was hurt. I am going to let the machinists and engineers in our airgunner community reading this explain theories of why this failure occurred, but I just wanted to make sure I let everyone know about this as soon as I got word of it.

Bigger picture statement... It is important for us as a community to inform each other of these kinds of failures to protect each other. IMMEDIATELY!

O-rings fail, guns leak, and stuff happens that we may not always share openly when things go bad with gear or brands we love, but when it comes to failures like this - YOU MUST SHARE.

Even if something was working great for you 9 times out of 10 - if something like this happens - SAY SOMETHING RIGHT AWAY. This goes not only for failures like this or bottle failures or failing safeties and trigger mechanisms, if something happens to you that is this level of a safety issue - TAKE ACTION.

Information is still coming in about this catastrophic failure and we will be providing more information as it comes to light.

[TrinityMaker]

Are you following up with Paul at PCP Tunes to see is he can explain why the regulator failed? Interesting it's made from cast aluminum. You can tell it's cast that has been milled by the way it broke. Not from a solid piece of bar stock like it should have been. It also seems too thin for 4500 psi pressures. I have the small regulator from PCP Tunes on my Condor. It's made from steel that's been powder coated. Too high of pressure is never a concern for me with that reg. The o-rings will fail before the body of  the reg fails.

Just out of curiosity, what was the pressure of the bottle when the reg blew out? Was it beyond 4500 psi?

[cobalt327]

Is this the regulator? https://www.pcptunes.com/airforce-texan-regulator-with-dual-gauge-v1.html

[TrinityMaker]

So I spoke with Paul from PCP Tunes regarding this failure, and he brought up some FABULOUS points. I will cut and paste the email I got from him. But before I do, I want to bring up some potential scenarios for "failure" of this regulator.

#1- The manufacturers suggested setting for the plenum side of the regulator is 200 BAR or less. Since the plenum is huge, you don't need higher pressures. You set up the rifle for a longer stroke of the tophat, which leaves the valve open longer and dumps more air from the plenum. When you read the stats from the PCP Tunes website (i.e. FPE, shot count, velocities) they are on a 140 gr slug. Probably in .308 caliber. The velocities are around 1000 fps. But if you step up the caliber to .45, and you're shooting a 220+ gr slug, your velocities are going to drop. You're not going to hit the same velocities that you will with a .257 or .308. But the regulator is adjustable. You have the ability to turn a delrin screw on the inside to raise or lower the bottle pressures. So you can potentially exceed the 200 BAR recommended setting on the plenum side of the reg. But just because you can doesn't mean you should. I can see where someone shooting the non-regulated Texan in .45 (who's achieving velocities of 950-1000FPS at the muzzle) would want to achieve the same thing with the regulator on it. Well, If you're not hitting those velocities at 200 BAR, turn up the reg to 210 or 220 BAR on the plenum side until you do hit those velocities.

 I have a 2 cylinder DAVV dive pump at home that I use to fill my CF bottles. The manufacturer recommends that you run it no longer than 15-20 minutes at a time, and let it rest for 15-20 minutes before running it again. Well guess what I did? I "ignored" the manufacturers suggestions, and I ran it for 35 or 40 minutes and exceeded (intentionally) the 4500 psi suggested pressure limit. I heard the sound of the compressor change at the 30 minute point, and I saw the temperature ont he high pressure side of the compressor drop drastically. After ripping the compressor apart, I realized I had broken the aluminum cylinder on the HP side, and I had to wait 3 weeks to have another one arrive. It was all my fault.

So was this failure do to a failure of the regulator because of poor manufacturing? Or was it due top operator error? And if was due to operator error, would the operator (knowing he ignored manufacturer suggestions) admit that he messed up? Now I'm not saying the guy this reg failed on is lying. BUT, given the testing done on these regulators, and given the materials, manufacturing standards, and QC, there's a probability that this reg failed due to operator error.

Those regs are made from 7075-T6 grade aircraft aluminum. If you're familiar with metal, that aluminum is almost as hard and durable as steel. There is no "casting" done. All components are machined from bar stock and sheet plates of aluminum. Here is a copy of the email from Paul at PCP Tunes. I have deleted some of the information he attached that talked about his "disappointment" in how this was handled. He can't understand why the concern wasn't brought to him before the video was pulled and he could ask questions and have the opportunity to defend himself and his product. But I only wanted to include the fact, not the emotion in his response.

Removed - direct violation of GTA Forums Rule #15.
15- Private Messages (pm) are just that, PRIVATE. As private emails are too. If any private communication from pm's or emails are posted in the gates the poster may be banned and message deleted.

[dyotat100]

Well you can't believe what they say because of the lies and lack of knowledge.

"With the reg set at 150 bar we shot the lyman 150gr collar button at 940 fps, and they were mighty accurate at long ranges"

150 bar is 2175 psi. A 308 texan with a 3000 psi fill would be lucky to get those numbers. That's 294 fpe on 2175 psi.

Next is the fact that he has said all along that the AF valve has a 3000 burst disc. They have always had a 5000 psi one. So the chamber was under built with the warnings of never go over 200 bar. But if the reg failed it would send 4350 psi into the chamber. Testing to a pressure does no good. They need to test until it fails. They could have been 10 psi away from failure when they tested to 300 bar.

Plain and simple they built something that wouldn't hold if the reg failed. Relying on the 3000 psi burst disc that didnt exist.

The chamber isn't large enough for a 257 let alone a 308 or 457. Chris's chrony numbers were down like 75 fps from shooting with no reg. That means it is not large enough for a 257.

I have a setup on my 50 cal and it makes 730 fpe. Shoots 375 gr at 936 fps on 3150 psi. I have 3 reg setups for my bigbores. They don't work unless they are large enough.

[UpNorthAirGunner]

He can't understand why the concern wasn't brought to him before the video was pulled and he could ask questions and have the opportunity to defend himself and his product. But I only wanted to include the fact, not the emotion in his response.

He can't understand why I deleted the video and posted the warning?  WOW.  Paul was very responsive and helpful during my testing of that regulator and as a person seemed nice to work with.  But Nice doesn't bring back people from death or being severely injured.  The person who actually relayed this info to me about what happened is a very trusted mutual friend to the person who this happened to.   The information was also relayed to Doug Noble as a technical resource to try and determine what caused the failure.  I am NOT an engineer nor the technical background to do an autopsy on what happened.  Doug and others are.  What I am though is a shooter and airgun advocate with a small but growing following. With that - it was 100% the right call to remove that video and to post the warning to all other airgunners.  If that somehow hurt PCPTunes' bottom line for sales or company reputation - that is NOT my concern nor focus.  Using gear that works and is safe and demonstrating that gear for other airgunners is my focus.  If Paul and PCP Tunes wants to bring another regullator to market I would highly suggest they send a reg to a trusted source for testing and technical / engineering review- but having that other one fail in such a dramatic and potentially deadly way 100% made me take a step back and realize I am NOT going to be someone's guinea pig.  Hope that makes sense.

[TrinityMaker]

I completely understand your points (both of you guys). I never even thought about the burst disc. I don't own the Texan regulator, so I've never held it my hand to inspect it. But I think the shape of the plenum in and of itself lends the design to weakness. It blooms out to a flat bottom on one end. I don't want you guys to think that I was insinuating that anyone was lying. I was just curious about the specifics of the incident regarding whether all manufacturer suggestions and specifications were followed.

According to Paul, they have beefed up the new version. He said the bottle side of the reg AND the plenum can handle 500 BAR now. I think the only way to test it is to put it through extremes. Pressurize the reg with a 4500 psi bottle and a valve assembly on it, and let it sit for a few weeks. Put it in a safe (explosion proof container). Then let it get extremely cold for about a week. Then let it get 120 degrees for about a week. If it survives those parameters, I think it should hold up. I FULLY understand your trepidation in even considering this.

Again, sorry if you guys thought I was insinuating lying or dishonesty. I know there are 2 sides to every story, and I'm grateful for the clarity.

I know you pulled the video Chris, so I have no reference, but what were your velocities with the reg. What did you have it set for? What were you shooting (projectile weight), and did you find the shots to be consistently accurate? Admittedly, I was super excited about this regulator. Now..... NOT SO MUCH!

[Pigboy1537]

Hello
    Thanks for the heads up. Something like this can can really hurt someone.

[mr3D]

Seeing as how no one else has tried to speculate on the cause of the failure I’ll take a shot at it. For qualification, I do have an ME degree, but my airgun experience pales compared to some of the other members here. As a DISCLAIMER I am not legally qualified to offer engineering advice. These are just my thoughts/opinions.

I would guess that this failure is the combination of:

1. The shape of the plenum. With any pressure vessel, the design goal is to eliminate any bending stress. This is why high pressure bottles have rounded end-caps. For any high pressure vessel, visualize what would happen if the vessel was made out of a flexible material like latex. If the SHAPE of the vessel would change with applied pressure it’s a poor design. Based on the photos of this plenum, it appears that the entire back section is flat, with a sharp corner transition between the body and back cap. If we apply the “made of latex” thought experiment to this shape, it’s easy to see that the entire back cap would balloon out into a rounded shape. To compound the issue, the sharp internal transition between body and back cap would act as a stress riser which brings us into:

2. The material of the plenum. According to the website, this part is machined out of 7075 aluminum. While aluminum can be very strong, fatigue will always be an issue, and is exacerbated by geometry that acts as a stress riser. Steel parts (like valve springs), can last infinitely if not stressed beyond a certain point, but aluminum will only last a certain number of cycles, regardless of how much it is stressed. Because of this, thorough testing of the part would have to include fatigue testing for a certain number of cycles and not just a max pressure test.

If anyone is interested, I could rummage around and attempt to do some calculations to estimate how many cycles this part would last for, but my bottom line is that I would like to at least see some design changes made for this to eliminate the bending stress incurred by having the flat end-cap. However, if this has already been beefed up it could very well be safe for many more cycles than it would realistically ever be used for. This is a situation where each buyer should do their best to understand the facts and make their own decision.