The DIY AOA probe: Bonding to pitot

[LettersFromFlyoverCountry]

I tried the idea of bonding the do-it-yourself probe for an angle-of-attack to the pitot tube the recommended way: with some JB Weld.



Alas, after a short period of time and a few hours of flight, it didn't work. It no longer bonds. So I have two questions (1) who's got an idea for removing old JB Weld and (2) who's got an idea for how to bond these?

[Mel]

That's interesting. I've been flying with mine for several years now and it's just like it was when I installed it. Were the tubes clean when you bonded them?
The only way I know of to remove JB-Weld is with a file or sandpaper.

[ChemGuy]

What metal is that? Al or SS?

I may have an MMA that can bond those.

[rzbill]

Hi Bob,
Instead of removing the JB weld, what about regluing the JB with some other epoxy, filling the gap so it is flush (tangent) to the two tubes. Let it cure. Then wrap the whole area with thread of a color you choose (like whipping the end of a rope) and then soak with epoxy.
I think a "composite" wrap like that would hold well. You could certainly get some carbon or something cool like that from ACS if desired.

[Sam Buchanan]

Originally Posted by LettersFromFlyoverCountry

I tried the idea of bonding the do-it-yourself probe for an angle-of-attack to the pitot tube the recommended way: with some JB Weld.



Alas, after a short period of time and a few hours of flight, it didn't work. It no longer bonds. So I have two questions (1) who's got an idea for removing old JB Weld and (2) who's got an idea for how to bond these?

Make a new one out of copper tubing and solder the tubes together.

I made a pitot-static for the Legal Eagle XL that is very similar to this and used proseal to bond the tubes together.

[rockwoodrv9]

How about a few wraps with some fiberglass tape, then west system epoxy. Flux to finish and shape, paint, done.

[deek]

Originally Posted by rockwoodrv9

How about a few wraps with some fiberglass tape, then west system epoxy. Flux to finish and shape, paint, done.

^^^ This, but I would add a tapered balsa trailing edge before glassing one side, allow to cure and then remove the last 1/4" of balsa to get a strong glass-to glass trailing edge close out. This would offer a sexy looking, strong, low drag, airfoil cross section assembly.

[curtis]

I took a little different approach. I installed two fittings in the access panel this way each probe that is in the airstream is securely held in place with or without the epoxy. I did bond the two together to make the assy one piece so if removed and reinstalled they would maintain the same position.



NOTE: I have since removed the Piper pitot/static probe.

[Andy Hill]

I too a different approach... I think I used ProSeal to bond/fair the pipes, but held them in place temporarily with lockwire.

The AoA line is in a (very) thin plastic tube inside the standard pitot tube, and exits later on via a T piece. I am sure it contradicts numerous standards, but works well except in/after heavy rain.

[Greg Arehart]

Originally Posted by Sam Buchanan

Make a new one out of copper tubing and solder the tubes together.

What about the weight penalty!

Here's mine, two tubes embedded in epoxy (AOA probe is on the bottom) based on Mel's design in another old thread: