Angle of Attack Indicator

[Pete D]

I would second Randy's concern RE the location on the rear spar. If I were building a CC with this option I would take that Top Cub Pitot bracket, turn it around and mounting it on the aft side of the front spar instead of the front side of the aft spar. This would put it forward of the front lift strut even at the high AOAs that a CC can get to.

The location you have is known to have issues with accuracy at high AOAs, the theory is that it is the front strut disturbing the air. We have not tested other locations though so it its theory at this point.

On compass location, you might hold a compass up in the fuse near where you anticipate mounting it and see if it deflects at all. Some areas of the fuse can have magnetic interference from welding. The other thing to keep in mind is what you are mounting it near. Wire bundles, especially high current ones and anything with a lot of power going through it, i.e. ammeter, com radio, etc can cause compass issues.

I had one airplane that was so bad (not a CC) that you could rotate the airplane 360* and the compass wouldn't move at all!

[DRL]

I would second Randy's concern RE the location on the rear spar. If I were building a CC with this option I would take that Top Cub Pitot bracket, turn it around and mounting it on the aft side of the front spar instead of the front side of the aft spar. This would put it forward of the front lift strut even at the high AOAs that a CC can get to.

The location you have is known to have issues with accuracy at high AOAs, the theory is that it is the front strut disturbing the air. We have not tested other locations though so it its theory at this point.

As you have suggested, I have now relocated it to the front spar, still in the same bay. The the holes on the bracket were reversed, but still lined up and there was only a minimal amount grinding necessary to make the mount fit. Not likely that disturbed air will interfere with it in this location. When we fly, we will report back if it functions correctly... it's usefulness is an open question.


6/20/14 Update

We have now flown with the AOA on the front spar, and it works just fine. One possible improvement would be to move the pitot location one bay further out on the wing. The reason for this is that on the ground, with a cross wind, we will sometimes get some air off the prop that sets off the AOA warning. The Dynon has a way to turn off the AOA below a certain speed so this is not much of a problem. The only downside putting it further out would be bumping into it.

In the air, the progressive audio works as advertised, it takes a few minutes to calibrate with a few stalls. The point at which the warning starts is adjustable, as is the warnings volume. The standard stall warning is very loud and it can overwhelm the AOA's, unless the headset volume is turned up high. For that reason, we may adjust the AOA's to start a bit earlier. Since it is very obvious when the airplane is getting close to a stall, it is unlikely anyone would miss all the clues, but overall, the Skyview AOA works great, and doesn't cost much to install on an EX for the redundancy.

DRL