AOA calibration

[Leonard_Smith_nz]

Dear Dynon,

I had a quick scan through the calibration process for the AOA tape of my D10A. It seems particularly cumbersome. I fly a RV6 and, within reason, the model is well understood and variability between different aircraft is not that great.

Why can't I simply enter the values manually and should they be off by a fraction I can add/subtract as needed.

Regards,
Leonard

 

[dynonsupport]

To do a basic AoA calibration only requires you to do one stall. Doesn't seem all that cumbersome. It does get more accurate if you do a few stalls.

There is a lot of variability based on installation differences for AoA. We can't just give you a number for an RV-6 and have it work at all.

The only way you'd know it was off was when you stalled the airplane. You just need to do one stall to calibrate it, which is the same maneuver you'd need to do to test it if we just gave you a preset.

 

[Leonard_Smith_nz]

Support,

Thanks for your reply. Two points:

1. My suggestion is for the owner/builder to enter the values manually...not at the factory (read initial post again). It's a simple matter for the pilot to stall the aircraft and to note whether a small increment / decrement is needed and then to adjust.

2. I'm confused by your "one stall" reply...I've just reviewed the Installation Guide again and it says 4 stalls required. Has the instructions changed?

Thanks,
Leonard

 

[dynonsupport]

2) We recommend 4 stalls for accuracy. It will work if you do only one stall.

 

[Jeff_R]

I am a relatively low time pilot and, even in transition training, we did not do full power stalls. So, at this early point in my test flight period, I don't want to do any full power stalls.

By the previous post, does this mean two power off stalls, one with no flaps and one with full flaps, should provide a good cal? (I have a dual Skyview.)

Also, can one do partial power stalls in lieu of the full power stalls? I guess the basic question is if the system knows or even cares what kind of stall you are doing? What even is the purpose of doing multiple types of stalls?

 

[dynonsupport]

The idea with doing multiple stalls is to ensure that you capture the one that has the wing at the lowest perceivable AOA (as far as the Dynon can see) of all of the configurations.

All that's going on during the stalls is the system is constantly saying "What's the highest AOA I'm seeing? Let's remember that for the end of the red zone". Do that a few times, and the lowest AOA that you see of those highest AOA values is the one that will trip the meter between the yellow and red.

Now, practically speaking, what that means is that you'll still likely get very good performance out of the AOA if all you do is put the airplane into its landing configuration, and then slow it up as if you were going to land. IE, do an APPROACH to the stall, dirty, power off, just like you are landing, and then stop and recover when you get to the end of your comfort zone. It won't put the yellow/red at a full stall, but it'll get it remarkably close, and if you want to stay a bit farther away from your actual stall AOA anyway, it will give you a more conservative AOA reading.

 

[Battson]

SO based on the above - the system determines (based on it's interpretation of measurements) at what point during the stall process the wing has stopped flying in a controllable way?
We are not able to tell it that ourselves with some configurable parameter?

Sorry - I have not calibrated my AoA yet (still building) so I dont know the process, but that sounds quite limiting given the variety of aerofoils and flight characteristics. The Bearhawk for instance is said to have no decernable "break" in the stall, so I am very interested to know how the calibration will determine when the red arc starts?

Cheers

 

[dynonsupport]

The system will set the start of the red zone at the lowest AoA of all of the stalls (or as close as you ever get to one) you show it during calibration (you can show it multiple aircraft configurations). So if you want it in the red at a specific point, don't achieve more AoA than that when you are calibrating it. It doesn't decide the stall is at a higher AoA than it ever sees.