Homebrew AOA Probe?

[Canadian_JOY]

I've plumbed the wing of our aircraft with an extra 1/4" plastic tube to accommodate a future AoA installation. I recently upgraded our GRT AHARS to the new Adaptive AHARS and included the AOA option.

I'm not in the mood to spend the big bucks for the Dynon heated AOA probe, nor to mount its electronics out in a finished wing. That leaves me with the task of devising a homebrew AOA probe. I've looked at the ingenious method employed by the RV12 gang (love that drilled rivet near the leading edge!) but our finished wing won't allow this option.

I've been giving consideration to installing something very simple immediately adjacent to the existing heated pitot - perhaps offset an inch or so outboard of the pitot so the AOA would receive some "bump protection" from the adjacent pitot. I've been thinking of using a piece of 1/4" 5052 aluminum tubing welded into a doubler plate. Drill a 1/4" hole through the wing, install the doubler from the inside, then bend the pipe to the appropriate downward angle. On the inside I'd likely go with just a Nylo-Seal 262-N union to adapt from the aluminum to plastic line. This could even be scaled down to use 1/8" tubing if one wanted.

What have others done to fabricate an AOA probe?

[lr172]

I have no experience here, but I would be thinking about installing an 1/8" tube projecting out of the bottom part of the pitot stalk. I think you are looking for something that angles down at 45* I would be concerned about the pickup being too close to the wing surface. There is a reason Pitot tubes are 4-6" from the wing surface and I would expect similar issues for an AOA pickup.

Larry

[Mel]

PM sent! xxxxxxx

[Canadian_JOY]

Thanks for the responses, Gents.

Larry - my wild hair-brained idea would be to have the AoA in close proximity to the pitot and at about the same distance from the underside of the wing. On our aircraft this would provide the additional benefit of making it harder to whack the AoA probe with heads, shoulders etc.

Over in the RV12 forum there's a really good discussion focused on using the typical Vans pop rivet (the same as used for the static ports) drilled into the wing at a point that will give a specific downward angle relative to oncoming airflow (60 degrees, if I recall). It's a very slick method of sensing AoA, much like the differential pressure ports used in the AFS AoA system. Unfortunately we can't get to that location in our wing (unless I get rid of the main spar - but I think we kinda need that chunk of aluminum LoL). This means the fabrication of a tube-based probe with the end bent downward relative to airflow. Should be fairly simple to make. Yeah, that's what they all say... *grin*

[xavierm]

Here are a few links:

https://www.thingiverse.com/thing:1121786

http://www.sonex604.com/aoa.html