Stearman project

Ewkearns,

What you say is true ONLY for those STCs that have been granted "duplication" approval. Most STCs nowadays are "One Time" STCs that apply ONLY to the aircraft it's written and approved for. (There's a LOT that's changed in Part 43 that you old-timers :grin: used to take for granted!)

I was lucky to recently find a duplicable STC that did exactly what I was trying to do!

Harvey
 
Ewkearns,

What you say is true ONLY for those STCs that have been granted "duplication" approval. Most STCs nowadays are "One Time" STCs that apply ONLY to the aircraft it's written and approved for. (There's a LOT that's changed in Part 43 that you old-timers :grin: used to take for granted!)

I was lucky to recently find a duplicable STC that did exactly what I was trying to do!

Harvey

No. If the paperwork was approved by a Designated Aircraft Maintenance Inspector(DAMI) (not an IA) it is good for all. DAMIs ceased to exist in 1956, but from around the end of WWII until then, their signature carried an ENORMOUS amount of weight. If you can find any of Bill O'Brien's writings on this, you'll have the full explanation. I think one of them was titled something about a "... 500 Pound Gorilla..." Your IA should know this....

I was teaching Part 43 up until 3 years ago, so I don't think I'm that out of touch. Don't lose sight of the fact that the certification basis for your aircraft is CAR Part 3, NOT FAR Part 23. Once you start "improving" the aircraft to Part 23 standards with Part 43 methods, you start down a slippery slope that allows the FAA to require any expensive and unwarranted alterations to airframe, powerplant, appliances, and anything else they can dream up.
 
ewkearns,

I AM an IA. Being a CAR3-certified aircraft only allows me greater leeway in parts substitution. Engine changes are another story and don't fall under the protection of CAR3 anymore.

I met and talked with Bill O'Brien about a dozen or so years ago at an IA renewal Seminar in Houston. He politely listened to my dilemma and just shook his head and apologized for not being able to help me because the FAA's lawyers had his, and the FSDO inspector's hands tied. Engine changes above/below 10% of the original horsepower can no longer be approved at the FSDO level but only in the FAA's Ok-City engineering offices, and they won't even touch such a request without pre-approved DAR and DER evaluations already attached.

It was Bill who made the statement that I quoted earlier about "...every engine known to man was bolted to the Stearman airfarme...".

Aviation lost a good man when Bill passed away!

Harvey
 
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Yeah, I liked Bill a lot.... and met him fairly often, as the school I taught at hosted pilot and mechanic FAA events. I remember his distaste for the lawyers. It really got under his skin that they would never actually define the term "airworthy" because they (in their words) wanted "wiggle room." That fuzzy math concept is probably a lot of what you are running uphill against. I'll bet that the 10% foolishness is more "policy" or "interpretation" than law. But, I saw this coming, years ago, as some FSDOs began to just flatly refuse to do field approvals. Period. That created a frenzy of FSDO shopping until the old hands, who took field approvals in stride, retired. Now, the FAA newbies look at it as something Regional, Oklahoma City, DERs, and DARs need to worry with, not them. I let my IA go when I retired. Don't miss it a bit....
 
Guys,

I've recently done some extensive repairs to my rudder frame (made up of welded 4130 steel tubing) and now I need to get the whole thing normalized (stress relieved). I've never had this done before. Can someone walk me through the process?

Thanks,

Harvey
 
Heat with a torch until it is red then let it air cool...that is all I do when doing 4130 repairs. Did you Tig? if so did you preheat? That is common when tig welding to do also. Tim
 
The term Airworthy is not speciffically defined in the FAR's, but it has been litigated to mean: Meets Type design and is in condition for safe flight
 
Love the project. I built a scale nitro powered model with my grandfather when I was a young boy. Partly because the Stearman was the first plane he learned to fly at the age of 19 during WWII. After training with the Stearman, he moved on to the SNJ-T6. Then he went into cargo type planes like the DC series and others.

I have always wanted to acquire a Stearman or SNJ but realize the cost to rebuild, maintain, and fly is out not economical right now.
 
Hmmmmm, I see some issues. If indeed, it is true that, "now I need to get the whole thing normalized," that implies heating the *entire* structure to (probably) 1600° F (check with the steel manufacturer). Heating the entire unsupported structure, for this process, is probably more of an exercise in inducing warpage than anything else. You may actually need a normalized and machined fixture to ensure that no warpage occurs sduring heat treatment. Or, you may consider straightening after the heat treatment, which kinda defeats the whole idea.. If the assembly is warped, after welding, and a close inspection can't relate given warpage to obviously induced welding stresses, you may end up with a real mess after normalizing.

It won't be much help, but you will probably need to cite and follow AC 43.13-1B CHG §4-1(c) and documents included by reference.
 
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