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GAP26 AOA Probe

R

rv8or

Well Known Member
I'm fitting A Garmin GAP AOA and have a couple of questions.

1. What type of fitting do you use to change from the aluminium tube to the plastic tube, note this fitting needs to pass through the standard pitot tube mount.

2. The power wires are very short so how have you connected them and if you had to extend them, what method did you use.

Thanks Rob
 
Cut the tube to give 1.5" clearance from the top skin (at least) and flare, it is a -3 tube.
Use a 90* -3 flare to 1/8" NPT adapter
Use a 1/4" push fit to female 1/8" NPT connector

Power wires - whatever is needed, crimp on additional wire using an in-line crimp, terminate the ground wire to a nearby ground stud.
 
FYI- if you decide to shorten the aluminum lines where they transition to soft lines, there's a minimum length spec in the garmin installation instructions in order to give some distance between the heated probe and the flex lines. I want to say it's 8" but my memory is a little fuzzy on that so please look it up if you go that route.
 
For the wires, I prefer the knife splice (handshake) terminals. Easy to disconnect and small. You could also use male/female spade connectors - 3/16” ones if you need smaller.
For the pitot and AOA lines there are several options. An easy one is to use the push on connectors if both aluminum tube and nylon tube is the same (1/4”). These work fine under positive dynamic pressure. Some of them don’t works as well under a negative pressure like you would see in a manifold pressure/vacuum line. You could also use a push on connector that has a male or female threaded end on one side, but that might not fit through the pitot mast. Another possibility is just get a piece of silicon hose with an ID that fits snugly over both tubes - it stretches.

www.steinair.com

Insulated Knife Splice Terminal- Splice Discinnect - Steinair Inc.

RED insulated 22-18awg crimp Knife splice disconnect Terminal. Knife splices are used in circuits that may need to be disconnected infrequently.
www.steinair.com www.steinair.com

www.steinair.com

Fitting, Straight Pitot Union Connector - Steinair Inc.

Straight Pitot Union Connector allows you to join 1/4″ tubing together.
www.steinair.com www.steinair.com

www.steinair.com

Fitting, Straight 1/8 NPT - Steinair Inc.

1/8 NPT pitot static fitting, straight connection. 1/4" tubing.
www.steinair.com www.steinair.com
 
rv8or said:
I'm fitting A Garmin GAP AOA and have a couple of questions.

1. What type of fitting do you use to change from the aluminium tube to the plastic tube, note this fitting needs to pass through the standard pitot tube mount.

2. The power wires are very short so how have you connected them and if you had to extend them, what method did you use.

Thanks Rob
Click to expand...
This is how I did it. Electrical will be uninsulated butt connectors, then covered with adhesive heat shrink.
20210828_121311.jpeg
 
Southern Pete said:
Cut the tube to give 1.5" clearance from the top skin (at least) and flare, it is a -3 tube.
Use a 90* -3 flare to 1/8" NPT adapter
Use a 1/4" push fit to female 1/8" NPT connector

Power wires - whatever is needed, crimp on additional wire using an in-line crimp, terminate the ground wire to a nearby ground stud.
Click to expand...
A cautionary note - for the RV 14, if the pitot is mounted in the left wing where Vans has you also locate the magnetometer (Garmin), grounding the pitot heat locally to a rib in the wing “may” cause enough magnetometer interference to fail the test (did in my case). I ran a dedicated ground wire back to the fuselage. Twisted pair of pitot heat wires routed away from the magnetometer may also be beneficial.
 
I must apologise, I realised I haven't replied and offered thanks for the replies, it comes with age.


I will use push fit 3/16 to 1/4 fitting as suggested.

For the electrical connections I will mount a small barrier terminal block that will give easy connections using ring crimps.

Thanks for the replies.

All the best
Rpb
 
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