Rocketman612

My Feedback: (85)

I purchased a Pilot 1 27% Stinson Voyager used last October. The plane is in excellent condition. I was surprised when I finally got to getting the wing on to do the CG and found the wing tube is bent. It must have happened when the previous owner was taking the wing off and dipped the wing. The tube is aluminum 5/8 in OD by 40.75 in long. I thought a little skimpy for a 109 in WS plane weighing 19 lbs. You can feel a ripple in the tube about 1/4 from the end. The wing half goes in about 1/2 way before you feel resistance. Putting the tube up to a straight edge it's a grunt over 2/16 in off.

I called Hobby Express and they do not sell a tube as a replacement part. TNT and Graphtec sell 5/8 in OD tubes but they are short. TNT is aluminum 30 in long, Graphtec is composite 36 in long.

My thought is to go with the longer composite tube and buy a shorter one then cut 4.75 inches off and splice it to the 36in tube with a dowel and JB weld. The splice is out at the end so stress on it should be negligible at that point.

I can do the same with the aluminum tube but the spliced tube would be longer 10.75in and I thought less desirable.

Any thoughts, suggestions are appreciated regarding either solution.

Pete

otrcman

My first thought would be to ask whether the composite tube is really as strong as the old aluminum tube. Yes, I know that pound for pound the composite is a stronger material, but how about wall thickness ? The composite tube wall thickness should be equal or only slightly thinner than the aluminum. Thin wall tubes are subject to local crippling, which is very much a function of wall thickness and not just material type.

Assuming that the composite tube is adequate in strength, have you considered putting half of the extension on each end of the 36" tube ? That way you would be extending each end only 2 3/8".

Last question: Does the model have load carrying struts, or is the tube the primary bending member ? If it's strut braced, then the tube is far less critical.

Dick

Rocketman612

My Feedback: (85)

Dick,
I had the same thought about the composite tube thickness and it's strength. They could have easily used a 7/8 in OD tube in the wing when designing it.

I did consider doing two splices not a problem that would make it even less of a problem of stress at the splice if any.

The wing does have struts that are made of wood and I'm sure carry some load. They are attached to a single point on the landing gear with a bolt and split to two attachment points to the wing bottom with a screw into a blind nut.

I have considered using either option of "Doubling" the tube by JB welding a smaller diameter (1/2 in OD ) tube into the 5/8 one to add some strength.

Pete

Lone Star Charles

I bent a similar wing tube once. I just replaced it with some 2024T3 tubing from Aircraft Spruce. - http://www.aircraftspruce.com/catalo...mtube_2024.php - It worked just fine.

Gort, klaatu barada nikto

otrcman

I agree with Charles. Buy aluminum of the same wall thickness as the original if you can. But be careful about the alloy. 2024-T3 is the good stuff. Any of the 5xxx or 6xxx series will be soft and easily bent.

Dick

Rocketman612

My Feedback: (85)

Bingo!!!
Had done multiple searches for wing tube material but didn't fine a good option other than TNT and Graphtec. Aircraft Spruce had the exact tube parameters 2024T3 ROUND DRAWN 5/8 in OD, Thickness 0.065 in and I got it at 48 in length for $40 shipped.


Thanks guys saved my keister

Pete
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