Longeron Tubing

[markc]

Hi Folks

Does anyone know the wall thickness on a 1965 Super Cub Longeon Tube??

[Frank T]

.035

[markc]

Thanks Frank

Much appreciated.

[fobjob]

.035 on the top, .049 on the bottom, as I understand it...... :-?

[Wayne Mackey]

.035 top and bottom from the piper factory. There are a few around that peaple have
put .049 on the bottom. Wayne

[fobjob]

By Jove you're right...it IS .035 top and bottom. I staggered out to my shed and applied the caliper to the old tail section I cut out, shortly after buying it 14 yrs ago...(Never throw anything away) Of course, the bottoms were telescoped with another .035 tube, indicating more unlogged major repairs to the airframe. Mmmmmmmm, .035, no wonder those lower longerons broke so easy the last time I pranged it!

[markc]

Fantastic. Much appreciated Folks.

[S2D]

Did they all have a foot of extra tube inside the lower longeron at the rear or just the A models?

[Wayne Mackey]

All the super cubs that I have cut open at that point had the inside sleeves at the
very back. Wayne

[Frank T]

The Liner Tube in the lower longeron at the tailpost end is an 8" piece of 11/16 X .049, turned down to .667/.660

Frank

[Crash]

Frank is correct. The 11/16" tubing size is hard to find. Northland Manufacturing makes the inner liners. I go a little longer on the top ones and roset weld them in place. Crash

[fobjob]

This has been a very interesting thread. Did Piper put those sleeves in to correct/prevent fatigue cracking back there, and more to the point, did Univair reinforce their replacement tail section similarly? Am I waiting for the welds on mine to crack? :o

[Steve Pierce]

I have found these on other rag wing Piper fuselages with nothing in the fuselage drawings.

[S2D]

Frank is correct. The 11/16" tubing size is hard to find. Northland Manufacturing makes the inner liners. I go a little longer on the top ones and roset weld them in place. Crash

What "top" ones? Don't remember seeing top ones or is this just an addition you make?

[Cub junkie]

I use 3/4 .065 turned down in my lathe for the inner sleeves at the splice and in the tail. Usually end up with about .045 wall for the inner sleeve. I rosette them like Crash does. I like to get a snug fit so I turn each one for its paticular location.

[Frank T]

Dillsburg also has the 11/16 X .049 it's like $2.50 per ft. They do now have a minimum order size. Their number is 717-432-4589

Frank

[R. JOHNSON]

Does anyone know a place currently selling 11/16" tubing that does not require a minimum order.

Thanks,

Ryan

[Mark Lund]

Try Air Parts in Kansas City. Sorry I don't have their number anymore.

Mark

[Bushwhacker Air]

Seeing as though 4130N is about 30-40% stronger than the 1025 Piper used in the cabin-aft end (the frugal Mr. Piper trying to save $$ from what Clyde Smith said) do any of you feel the need for the liner with the .035 4130N lower longeron? Using all .049 lower longerongs would weigh about a 3 lb. more, less if you don't use any sleeves (they must weigh a pound or more)

[Jeffrey Flinn]

I do not see that size on Air Parts website but I'd call them as I know we have purchased some before............

https://www.airpartsinc.com/shopexd.asp?id=1058

[nesincg]

Jeff,
Did you ever have any luck finding 11/16, at a reasonable price? I found some that was $13.50 per foot :o.

[R. JOHNSON]

Chris,

Where did you find it for $13.50? I'd be interested even at that price.

Ryan

[cruiser]

On a J-5/PA-12 Piper fuselage frame drawing that I have the liner is noted on the lower longeron at the tail post as view "E", which I do not have and at the front gear fitting as tube #2333, 665-.035 4130 9 1/2" long. Jim

[flybynite]

I found some at http://www.factorysteel.com/aircraft-tubing.htm That was April, 2010. As I recall they did have a minimum order, but 8 ft of 11/16" made the minimum :-(. It was expensive and did not slide right into the 3/4", 035 wall longeron.

If you use 3/4 .049, then you can use 5/8" liner tubes. The 5/8" liner would also work for the .035" wall longeron but would be a sloppy fit.

Wayne

[nesincg]

That link was the same place I found it today. 12 feet + shipping was going to be about $183.