Nitrogen rig question

[icefr8dawg]

not bigger or stronger just smarter. I don't know what piper was thinking using cheap thin galvanized metal in a hot exhsust area... Stainless was the fsdo's idea

 

[avbug]

Not necessarily smarter.

The manufacturer can approve material substitutions, whereas the FSDO can't.

Field approvals are not a local approval any more, either.

Remember that a patch made of dissimiliar metals means corrosion, to say nothing of strength, and in some cases with proximities of different coatings and materials, embritlement and other issues, too.

While a change to a commonly used firewall material like Stainlessmight sound smarter, it's not necessarily so.

 

[icefr8dawg]

I suppose one could have fixed the problem with $20.00 of NAPA exhaust wrap fifteen years ago but, oops, that's almost 100% non pma isn't it?
These planes just weren't made to last the way we've demanded.

 

[avbug]

PMA isn't really relevant. The airplanes were made to last indefinitely, so long as they're maintained.

 

[icefr8dawg]

Perhaps made to last forever with a total and complete teardown every now and then. My point was they, Piper and Cessna really messed up in the old days when they chose inferior materials in certain areas. 1960's and 70's mostly.
And my J-3 has a 4130 repair where it had good old 1943 mild steel, no engineering or stress analysis, just "better" and there isn't a fed that would fault me for welding it in that way. Most couldn't light a gas torch without blowing themselves up for that matter.

 

[avbug]

Also not particularly relevant. Further, if you think you're successful because the local FSDO doesn't bust you, remember that whereas the FSDO doesn't have the authority to interpret regulation or grant liberties not available from the manufacturer or national, another FSDO certainly has the right and opportunity to pursue enforcement action or declare a repair unairworthy...an important point during a sale, later inspection, or in the event of an incident involving any legal action (such as an insurable event).

Simply substituting something because you think it's "better" is isn't bright, nor legal. The subject is a whole lot more complex than such simplistic thinking.

 

[erj-145mech]

My point was they, Piper and Cessna really messed up in the old days when they chose inferior materials in certain areas. 1960's and 70's mostly.

Do you think that Cessna and Piper built thousands of aircraft inferior materials, and the Federal Government turned its back?

The materials and the processes met the standard at the time. Just like your private pilot checkride, it also met the standards at the time. Now a days, the applicant must be proficient in radio communications and VOR navigation.:laugh:

The Volkswagon Beetle, thousands were sold in the US in the 60's and 70's. Until recently, they were built in Mexico and Brazil, but none were sold in the US. Do you know why? Answer is that they didn't meet the current standards. If the new Piper company were to certify your J-3 under the current standards, it wouldn't pass muster either.

 

[Frozen Ronin]

For kids sake, Avbug! What you ought to be asking this guy is if he is using high pressure nitrogen or if he's got a step down regulator!!!! He's made up his mind, and the FAA really won't care.

Nitrogen rigs can be either high pressure, for using on 121 type struts, or low pressure, such as for GA struts (amoung other things). The bottles used are the same, 3000 psi. The difference is in the regulator rig, and that's where the pressure is stepped down for GA stuff, tire servicing and the like. You could really hurt yourself, no, you can KILL yourself if you use the wrong one. This, in my opinion, is far more important than if you use shop air versus nitrogen, no?

I know of more than one mechanic that died because he hooked up a high pressure rig to a low pressure strut. This is no joke, don't dismiss it, do not pass go and do not collect 200 bucks.

Be safe.

Ronin

 

[avbug]

I believe we already addressed the issue of putting too much pressure to the strut, right off the bat. A regulator is a regulator...perhaps you're talking about strut pumps. The poster was never asking about that. The poster wasn't asking about a strut pump, or a regulator,though I did caution him or her about putting too much pressure to whatever he or she is pumping (particularly if they think it isn't moving because the shraeder valve isn't open...).

What the poster was asking about was a threaded adapter to attach at the shraeder valve or filer valve...and that adapter fitting won't change the pressure at all.

A strut pump is a horse of an entirely different color.

 

[Frozen Ronin]

Ah, now we shift the focus to debating my facts. If you'd like, I'll go into how regulators are drastically different for high and low pressure. Maybe in a different thread. Most of these differences stem from loss of life. I wonder if those who were injured or killed thought that all regulators were the same? I think the point is being missed on this one.

The adapter is very important as far as pressure, as well.... many operators are going to a larger shrader or filler valve to show the difference between high and low pressure applications. This goes for tires to accumulators to e bottles to struts. It's all in the name of safety.

Strut pumps are fun, when you don't have high pressure available. I've not read any loss of life related to them, but that doesn't mean it hasn't happened.

Ronin