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1940 Stearman restoration (moved from Triumph forum so all can enjoy)

drooartz

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Fantastic stuff, thank you for bringing us along on this journey of yours.

Really makes me glad I didn't get into airplanes, the cars are challenging enough!
 

JPSmit

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Fantastic stuff, thank you for bringing us along on this journey of yours.

Really makes me glad I didn't get into airplanes, the cars are challenging enough!
Sometimes the idea of driving something I have worked on seems scary enough - never mind flying something I have worked on.... :D
 

DrEntropy

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I think I'd have confidence in my work on an aircraft, but I'm also so A.R. it'd never get finished! :p
 
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Ah, thanks for moving. Hey, if we get 98 more Stearman owners we can start a Stearman forum!
98 Stearmans flying around, 98 planes in the air. One comes down, lands on the ground.......97 Stearmans flying around! See what you caused there Basil!! LOL :D
 
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CJD

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Hey, thanks for the support guys! Since this got moved I haven't checked on the thread, and am overwhelmed with the interest. I have been working on the old girl regularly, but it's not very interesting. I am finally to the stage that parts can start to go back onto the frame...so I decided that before the building starts, I should have all the small steel parts and nuts and bolts that are in good condition re-cadmium plated. The plating shop charges a minimum job of 100lbs. As you can guess, I have learned that 100lbs of mostly nuts and bolts is a LOT of nuts and bolts! I have to inspect them, toss any that are bent, damaged or worn, and chase the threads. Oh...yeah...the worst part is that the paint has to come off, as that fouls up the plating.

Uhgg. I long for the days behind a welder where I could see progress. I am making progress, but it doesn't show anymore.

It's funny, in that the newer urethanes come off easily. I can fill a jar with stripper and a handful of bolts, and the urethane falls right off. The zinc chromate is immune to all the strippers I have tried, though. And, zinc chromate is the main paint on all the parts! I am therefore spending many hours sitting over the bead blast cabinet, taking paint off. My days are spent removing steel parts, cleaning them in the solvent tank, and blasting them bare. Not very interesting, but necessary before I move on to the assembly.

So, here are some interesting finds I have come across:

AcCksUf.jpg

This is one of the tail flying wire shackles...holding a flying wire to the stabilizer. The blueprint calls for 120kpsi ultimate strength alloy steel. As you can see, someone thought brazing it would be fine (about 30kpsi, or 1/4th the strength). Of interest is that it survived the crash!


ELZ015k.jpg

This is the gearbox for the elevator trim tab. I get the impression it has not been lubed recently, since the grease came out in rocks.


0f1acQB.jpg

This is the original engine mount, post crash. I was actually planning on rebuilding it, but:


NFnUIMz.jpg

When I cut the damaged metal off and looked closely at the mounting ring, the entire ring had been bent in ward, like a cone shape. When I looked closer, the PO had welded a couple spots where the engine had rubbed against the ring and cracked it. If you try to follow me...the engine could only have contacted the ring if the ring was previously bent, and the plane flew for a goodly amount of time to cause cracks and try to weld them. In short, the ring was coned long before the crash I am fixing. Go figure.

But, I could not think of any way to press the cone shape back out of the ring...it was junked.

Bummer.
 
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CJD

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YiNZQC5.jpg

Fortunately a local Stearman fanatic had a replacement engine mount, so I am back in business...with a little less money, but at least 2 weeks of work saved. This is the new (old) engine mount after blasting and coating with that fantastic BRG paint!

Last of all, here is the spindle that holds the tailwheel, allowing the tailwheel to turn.
OhiW9Av.jpg

The inside of the bore should be smooth for a felt seal to ride on, and there is a snap ring groove that holds the whole thing together...only the groove is gone! The snap ring came out, and the plane was flown for some time with the bearings flopping around, causing all this damage. I will attempt to weld up the inside and re-bore it to shape. If I don't succeed it'll have to be replaced.

In closing, I remember flying with a copilot many years ago who had welded the frame on his home-built plane. I told him I was reluctant to trust my life to my welding skills. His response was "maybe your skill isn't as good as you think". I responded that "having been welding for 45 years, perhaps I have been welding long enough to know that a perfect looking weld on the outside can be weak on the inside". The story goes that, although the PT-17 was only rated to +6 and -3 G's...Boeing tested it to +15 and -9 G's...and could not get it to go fast enough to test any higher! Near the end of WW2 a bored instructor decided he was going to pull the wings off a Stearman, just for something to do. All he did was G himself to unconsciousness, and when he came to the plane had righted itself and was putting along straight and level. I am still reluctant to trust my welding, but after seeing how tolerant this old Stearman is to abuse, I feel confident I can at least make it safe again!
 

2002S2000

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I'm enjoying the update and progress John. However, the pictures in the above 2 posts aren't loading very well on my end. I'll give it some time and check back.

Happy New Year!
 
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