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Anna

Active Member
Hi all!

I have the Dynon Pitot Tube and the Pitot Static Kit from SafeAir1. The Kit includes a fitting to connect the aluminum tube from the Pitot tube with plastic tube provided in the Kit.

My Question is how to fix this fitting in the wing?
I think the best thing would be, to fix the fitting in the already drilled holes in the rib.

Do you think I can use a lock nut to install the fitting in the rib?


Best regards
Anna

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It's hard to tell what fitting you have with both ends covered. There is a fitting that is intended to fit in a bulkhead and is longer to accomodate the additional nut to hold it in place. (AN832)

AN832C.jpg
 
Lots of different ways to do it

Anna, I have spent recent weeks mulling over this same question. Some different possibilites are:
1. Mounting an angle bracket to the forward web of the rib to provide a mounting platform for some ADEL clamps securing the aluminum pitot tubing so that the entire fitting assembly fits easily into the big lightening hole

2. Shortening up the pitot tubing so that the fittings are closer to the pitot tube and not anywhere near the rib. Just insert the air lines through the tooling holes after inserting grommets or snap bushings into the same holes in your pic

3. Your suggestion to mount the fitting through the tooling hole.

I have decided to use Option 2. That basically allows me to create a small service loop with the SafeAir1 tubing and then run those lines straight through the grommets or snap bushings in the tooling holes of the rib. What you ultimately decide to do depends in large part on where you decide to mount your pitot tube and if you are comfortable trimming down the aluminum tubing on the pitot tube.

Here is a link to Steve Riffe's build log with pics of his final solution that I really like.

http://www.mykitlog.com/users/display_log.php?user=skyking90200&project=832&category=6117&log=123059&row=69
 
I did mine in the nr 2 option as well. Something I found was the wing skin alone was not stiff enough to support the mechanism, and I had to put a doubler on to make it more steady.
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Thread tape?

I had a question about using teflon thread tape on the brass tubing adapter to an fitting. I know not to use thread tap on AN fittings, but it seems the adapter has a tapered thread and does not seal on the flange therefore requiring thread sealant. I know we're not dealing with very large pressures here (0-2psi maybe) but I would think any leak could be really detrimental to reliable airspeed/AOA info.
 
RVZoomie said:
it seems the adapter has a tapered thread
Click to expand...

Precisely. National Pipe Thread (NPT) is tapered, not straight.

A search here will turn up gazillions of threads (no pun intended) on tapered threads and how they seal, what to use/not use, etc.

If you use a regular straight tap, you'll just tear it all up...
 
If you don't seal pipe (tapered) threads you will have pitot-static leaks. Teflon tape is fine on pitot-static lines.
 
I was mainly commenting because the pictures in the thread as well as the pictures in the kitlog I couldn't see evidence of thread sealant (not that you always can). Mine is currently installed with thread tape.
 
I shortened and staggerd the aluminum tubing coming out of the pitot and have plenty of room to slide the tubing in and out of the SafeAir fittings. YMMV though as I have plenty of room in my -10 wings and I don't know how much is in other models.
 
Sealing Threads

I used Permatex thread sealant where the fittings screw together. I does not show up in the pic on kitlog--think I actually added it later on. I agree that the fittings need some sort of thread seal and the Permatex seems to be easier (at least for me) to work with than teflon tape.
 
Anna, that can work as is...maybe. You can cut a stub of clear vinyl tube the right length (1/2 in.?) and slide it over the AN fitting after you poke it through the bulkhead. When you tighten the brass fitting it will compress the hose and wedge it tight against the bulkhead. Trick is cutting the hose stub the right length so it bunches tight just as your fittings torque up. You can also slip a washer between the vinyl hose and the brass if it tries to slide over the brass.
 
Thank you very much for all this helpfull answers!

Tdk, I think we need a 3/16" NPT.

I would prefer the solution with the AN832 fitting.
 
This all seems like a whole bunch of extra work, and potential leaks.

I just flared the tubes coming out of the pitot tube and bent them to fit around the pushrod, etc., then used the combination flared tube fitting/brass NPT quick-release, and thence plastic tubing in grommets all the way into the fuselage T-fittings (to split it to an EFIS and an ADAHRS).

The guy who did the static/XPDR check (and pitot check) was impressed...no leaks right from the word go.

Why are you complicating things? What am I missing here?
 
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