Shrinking inner sleeve

[mhorowit]

A splice by inner sleeve requires an inner tube with an OD just under the ID of the original tubing.

I've been splitting the tube, removing a 5/16 lengthwise piece and then squeezing the tubing in a vice, trying to keep it round. I'm running a bead along the seam, then grinding it down. Finally, I chuck it in my drillpress and file to fit.

Is there an easier /smarter way to do this? - MikeH

[Guest]

Re: Shrinking inner sleeve

Hi Mike,

I have never had to work that hard at it, I think you have selected the wrong size inner sleeve.

What dia. and wall size are you using?

Dave

[N96337]

Re: Shrinking inner sleeve

Mike, AC43 allows you 1/16" slop in the two diameters (that doesn't sound like much now, but looks like alot when it's in place).... from what you've said, you're not following their instructions correctly, not to mention making alot of extra work for yourself. On very rare occasions, when I needed a snug inner sleeve to keep alignment, I've chucked a thicker walled tube in a lathe and turned the outside down to match the inside of the other tube. AC43 states that you have to have the same material and at least the same wall thickness in both tubes..... they don't address splitting the inner tube anywhere that I could find. You do have an AC43.13-2A there don't you?
John

[mhorowit]

Re: Shrinking inner sleeve

Mike, AC43 allows you 1/16" slop in the two diameters (that doesn't sound like much now, but looks like alot when it's in place).... from what you've said, you're not following their instructions correctly, not to mention making alot of extra work for yourself. On very rare occasions, when I needed a snug inner sleeve to keep alignment, I've chucked a thicker walled tube in a lathe and turned the outside down to match the inside of the other tube. AC43 states that you have to have the same material and at least the same wall thickness in both tubes..... they don't address splitting the inner tube anywhere that I could find. You do have an AC43.13-2A there don't you?
John

I think it was a trick allowed during the time of the CAA - Mike

[mhorowit]

Re: Shrinking inner sleeve

Hi Mike,

I have never had to work that hard at it, I think you have selected the wrong size inner sleeve.

What dia. and wall size are you using?

Dave

Dave - taking the same dia. and wall thinkiness as the original, cutting it down to form an inner sleeve; replacing the last 8" of the bow at the wing-tip. That's a 1/2"OD with a .003-.004 wall thickness. - MIke

[Guest]

Re: Shrinking inner sleeve

Dave - taking the same dia. and wall thinkiness as the original, cutting it down to form an inner sleeve; replacing the last 8" of the bow at the wing-tip. That's a 1/2"OD with a .003-.004 wall thickness. - MIke

Mike, don't do that. I don't recall that being approved in 43.13. Just get the next smaller tube.

Also the wingtip bow is a secondary structure so you can just braze the joint too. Check that out in ;

of metal-joining processes in which the bonding
material is a nonferrous metal or alloy with
a melting point higher than 425 C (800 F), but
lower than that of the metals being joined.
Brazing includes silver brazing (erroneously
called silver soldering or hard soldering), copper
brazing, and aluminum brazing.
NOTE: Never weld over a previously
brazed joint.
a. Brazing requires less heat than welding
and can be used to join metals that are damaged
by high heat. However, because the
strength of brazed joints is not as great as
welded joints, brazing is not used for structural
repairs on aircraft. In deciding whether brazing
of a joint is justified, it should be remembered
that a metal, which will be subjected to a
sustained high temperature in use, should not
be brazed.

4-104. STAINLESS STEEL STRUCTURE.
Repair structural components made
from stainless steel, particularly the “18-8” variety
(18 percent chromium, 8 percent nickel),
joined by spot welding, in accordance with the
instructions furnished by the manufacturer,
DER, or FAA. Substitution of bolted or riveted
connections for spot-welded joints are to
be specifically approved by a DER or the
FAA. Repair secondary structural and nonstructural
elements such as tip bows or leading
and trailing edge tip strips of wing and control
surfaces by soldering with a 50-50 lead-tin solder
or a 60-40 lead-tin solder.

Dave.

[Forrest Barber]

Re: Shrinking inner sleeve

Mike if you see hoof prints don't think Zebras Just select the next smaller tubing and go for it. Wing tip bow? make a new one .

[mhorowit]

Re: Shrinking inner sleeve

Mike, don't do that. I don't recall that being approved in 43.13. Just get the next smaller tube.

Also the wingtip bow is a secondary structure so you can just braze the joint too. Check that out in ;

of metal-joining processes in which the bonding
material is a nonferrous metal or alloy with
a melting point higher than 425 C (800 F), but
lower than that of the metals being joined.
Brazing includes silver brazing (erroneously
called silver soldering or hard soldering), copper
brazing, and aluminum brazing.
NOTE: Never weld over a previously
brazed joint.
a. Brazing requires less heat than welding
and can be used to join metals that are damaged
by high heat. However, because the
strength of brazed joints is not as great as
welded joints, brazing is not used for structural
repairs on aircraft. In deciding whether brazing
of a joint is justified, it should be remembered
that a metal, which will be subjected to a
sustained high temperature in use, should not
be brazed.

4-104. STAINLESS STEEL STRUCTURE.
Repair structural components made
from stainless steel, particularly the “18-8” variety
(18 percent chromium, 8 percent nickel),
joined by spot welding, in accordance with the
instructions furnished by the manufacturer,
DER, or FAA. Substitution of bolted or riveted
connections for spot-welded joints are to
be specifically approved by a DER or the
FAA. Repair secondary structural and nonstructural
elements such as tip bows or leading
and trailing edge tip strips of wing and control
surfaces by soldering with a 50-50 lead-tin solder
or a 60-40 lead-tin solder.

Dave.

Dave -

1. I found the section on brazing in section 4-88. Defining "non-structual elements" (yes, I see it specifically calls out my bow tips!) looks to be a slippery slope; obviously the fuselage is structual. Does this mean all the tabs can be brazed? Is there a good definition of what is considered 'structual?

2. Para 4-104 is discussing Stainless Steel; it talks about soldering, not brazing and I think their discussion is specific to Stainless. Am I incorrect?

Please point out if I'm doing anything incorrect - I"m in one of my "focused" modes, and don't see other solutions. - MikeH

[Guest]

Re: Shrinking inner sleeve

Dave -

1. I found the section on brazing in section 4-88. Defining "non-structual elements" (yes, I see it specifically calls out my bow tips!) looks to be a slippery slope; obviously the fuselage is structual. Does this mean all the tabs can be brazed? Is there a good definition of what is considered 'structual?

2. Para 4-104 is discussing Stainless Steel; it talks about soldering, not brazing and I think their discussion is specific to Stainless. Am I incorrect?

Please point out if I'm doing anything incorrect - I"m in one of my "focused" modes, and don't see other solutions. - MikeH

My point with the stainless section was only that they define bows as non-structural

[mhorowit]

Re: Shrinking inner sleeve

My point with the stainless section was only that they define bows as non-structural

Got ya.
How would you explain to a class what is structural and what isn't? Vertical Stab? - MikeH

[astjp2]

Re: Shrinking inner sleeve

Just replace the bow, It took me 1 hour to make a new one and you have spent more time than that on discussing it on here. The bow is non structural because it is not a load carrying member, it only gives shape. Tim

I know lots of IA's that even can be quoted saying that the ribs are nonstructural. I know that comment will tend to cause a heated discussion.

[mhorowit]

Re: Shrinking inner sleeve

Just replace the bow, It took me 1 hour to make a new one and you have spent more time than that on discussing it on here. The bow is non structural because it is not a load carrying member, it only gives shape. Tim

I know lots of IA's that even can be quoted saying that the ribs are nonstructural. I know that comment will tend to cause a heated discussion.

I hear you.
How do you bend your tubing?
I've been filling it with sand, plugging ends and use as long a lever arm as possible. - MikeH

[astjp2]

Re: Shrinking inner sleeve

I just use a large tire, it wont kink if you work it slow. Another method is to screw down a piece of round wood about 6" diameter to a bench and another block to bend against and form it around. I quit filling with sand because the large radius of a bow should not kink and it was a waste of time for me. Tim

[fearofpavement]

Re: Shrinking inner sleeve

A rib non structural? That's quite a reach in my opinion...

[mhorowit]

Re: Shrinking inner sleeve

I just use a large tire, it wont kink if you work it slow. Another method is to screw down a piece of round wood about 6" diameter to a bench and another block to bend against and form it around. I quit filling with sand because the large radius of a bow should not kink and it was a waste of time for me. Tim

If you wanted to bend two gentle "s" curves in a distance of three feet, how much tubing would you start with? I"m trying to visualize how much lever arm you use. - MikeH