Tubing size

[Elkonastick 10]

Hi all,

After an off airport landing on a dirt road I noticed my tailwheel had sheared off, mount and all. Doing some research it looks like the bottom and angle brace tubing to tailwheel mount on the MkIV’s are known to crack over time. Mine sheared right at the tailwheel cradle and diagonal brace where it attaches to through tube for the tow bar. I’m going to repair and strengthen 

What size tubing will slide inside the 1/2” .035 lower tubing? 

Thank you 

Edited 10 Aug 2020 by Elkonastick
Added pic

[TJay 1041]

You will need a tubing with an OD of .465 Maybe a good time to stretch it too

[Elkonastick 10]

It was stretched by Brett at Airdale in 2012, 13.5" along with adding height to vertical and bigger dorsal. It has a Matco tailwheel and from what I'm finding the bigger tailwheel seems to contribute to the cracking and eventual failure? 

Thanks for the info on tubing size, I have a few sizes buddy is bringing by so hopefully he'll have a chunk of the .465.

Thanks again

[Odysseus 1]

1/2-in OD tubing that has a 0.035-in wall has an ID of 0.43-in (0.5 - (2 x 0.035).  The nearest size of 4130 tubing that I see listed anywhere is 0.438-in, which is 0.008-in larger OD than your existing tube ID.  You may need to either ream slightly, or use a small tubing expander to get it to slip inside.  It looks like the lower tubes snapped right at the forward end of the tail-wheel mounting plate.  My thoughts are that you may need to add gussets to the sides of vertical stabilizer tube joint (lower left side of the image) and add diagonals from the front of the tail-wheel mounting bracket up to the upper tubes for more support.

[1avidflyer 1983]

I have a piece of 7/16" tubing I've used for inner sleeves, it may be .058" wall, but when I make a sleeve,  I cut through it on one side with a thin blade on my 4 1/2" side grinder so it will squeeze down a bit when you slide it into the 1/2" tube.  JImChuk

[109jb 181]

I have a piece of 7/16" tubing I've used for inner sleeves, it may be .058" wall, but when I make a sleeve,  I cut through it on one side with a thin blade on my 4 1/2" side grinder so it will squeeze down a bit when you slide it into the 1/2" tube.  JImChuk

This ^^^^^^

[skelly 12]

When I did my longeron repairs I was in the same boat as you.

I bought some 1/2 OD material with a .083" wall thickness then turned it down in the lathe so that it slid nicely inside the original tubing while retaining around .040" wall thickness.

Skelly.