AOA calibration and full power stalls.

[cigogne]

Hi,

I'm building a Gaz'Aile aircraft (gazaile261.free.fr/indexAE.html) and plan to installing a Dynon glass panel (SkyView, radio, AutoPilot, transponder, 2x10" displays....).

I read the manuals thoroughly (for documentation sake... and also to dream a bit to be honest!) and I'm not sure about the "with full power" AOA calibration process…. May be because of my English… :-[

Does this mean that we have dynamically stall (this would be unsafe for the structure especially with full flaps)? More likely are the "with full power"  tests (no flaps/full flaps) used to setup the AOA for taking off and go-around conditions? In this instance the test would consist in slowing down very close to the stall (by jotting down the stall speed found with no power in the same configuration), hit “STALL” button, go to full power, and pull the nose up to enter the stall.

Am I guessing right?

Thanks and regards. 

 

[Dynon]

Close. The basic idea here is that you show SkyView what high AOA (the stall) looks like in different configurations. The general procedure in SkyView is (this is slightly different than our D10/D100 series products)

1) Fly a fast cruise with a few pitch oscilations to show SkyView what low angle of attack flight is
2) Stall in some configuration (it doesn't matter which)
3) Recover
4) Press the Stall button to let SkyView know you've just shown it a stall
5) Repeat 2-4 for as many configurations as you like
6) SkyView ensures that all of the demonstrated high AOAs in different configurations all result in a stalled indication

Some pilots find that because of particular wing designs, or sometimes in high powered aircraft, that demonstrating stalls in configurations can have such radically different perceived stalling AOAs that they get better results by only some, or even perhaps one configuration (usually the landing configuration) to calibrate the AOA. Since the process is so easy - it literally takes a minute or two - you can basically experiment to see what's right for your aircraft.

 

[cigogne]

Thanks for your reply. I got it now.
As a matter of fact I misread the manual.... for some reason I interpreted that the system was asking for a specific configuration, then the second one etc.... when this is not the case.
Thanks again.

 

[howardnmn]

I am having trouble reading the instructions on the skyview screen during calibration/stall. I would like to print them out on paper but can't find them anywhere. Can dynon support pls provide a .pdf or equal?

 

[paul330]

Download from Support/Product Documentation........

 

[Pegaz]

I believe that I understand, this is found in what product documentation and where ?

 

[paul330]

It's in the Skyview Installation Manual. Unfortunately, it simply says go to the calibration page ion-screen and follow the instructions.........

 

[Dynon]

Here are the instructions from that screen:

 

[Richowen2]

Hi, I have an RV 10 with the Skyview system, and heated pitot with AOA sensor.
I tried to calibrate the AOA today, as per the on screen menu.
I did 4 stalls, all at different power settings and configurations.
After each stall, I pressed the stall button, and it registered the stall on screen.
After the 4 stalls, I pressed the save button, and the AOA showed up on screen.
I thought everything was fine, until I joined the circuit, and at about 80kts, the AOA warning started sounding!
It remained on all the way untill after landing!
So clearly, the calibration didn't work!!
Does anyone know why, and what I need to do to correct it?
Thanks.

 

[Carl_Froehlich]

I have an RV-10 and found the AOA calibration to be straight forward. Perhaps your multiple power setting approach is the issue.

Recommend starting over and do just the no power, full flap stall. That is what I did and the AOA tone warning is amazingly accurate for landing. I get the first few beeps right before the final pull for flair. If I get beep before this I know I'm too slow and/or stretching the glide.

Carl

 

[Richowen2]

Thanks for your reply Carl.
I figured that perhaps I confused the system with too many stalls!
I will go out and do it again with just the landing config stall.
Let you know.
Thanks.

 

[swatson999]

This is one feature I'd still like to see Dynon implement...being able to use flap position information for the AOA indication, so that it's as correct as possible for flaps-up flight vs. flaps-down landing configuration.

It works great as is, and of course landing is where I'm most interested in AOA and where the beeping is most useful (and adds to safety), but it really ought to know *at least* the difference between flaps up and full slaps down when computing AOA and annunciating it.

That's about my only complaint with the system, though...other than that, I love the AOA indication!

 

[n456ts]

This is one feature I'd still like to see Dynon implement...being able to use flap position information for the AOA indication, so that it's as correct as possible for flaps-up flight vs. flaps-down landing configuration.

Good idea!

 

[jacktunnell]

I did the same as Carl with the same results in my Sportsman. I wanted to just hear the start of the beeping as I slow down on final so I recalibrated with no flaps. It is just a bit too high so I will try recalibrating at first notch.

Setting the AOA seems to be a process, not an event.

 

[dynonsupport]

When you hear the beeping is adjustable in the audio menu. You should calibrate it so it goes solid at or before the break of the stall, and then use the audio menu to adjust when it first becomes audible.

 

[Tuiliere]

Hello Dynon,

I calibrated my AOA today on my RV7. All is fine. A very good tools to help me for landing. But...when I am landed, the AOA bip continue in my headset until the speed is under 20 kt. Would it be possible to stop it under 40 kt for example (stall is 50 kt) ? Perhaps in the setting menu...
In advance thank you
Sylvain

 

[Raymo]

Page 4-26 in the installation manual, Rev Y.

INHIBIT AOA BELOW AIRSPEED – Allows you to set an airspeed below which no AOA tones are played. This helps prevent nuisance alarms while on the ground and
taxiing, especially in tail draggers.

 

[Tuiliere]

Thank you so much !

Nice day,
Sylvain

 

[shenweas]

I have an RV-10 and found the AOA calibration to be straight forward.  Perhaps your multiple power setting approach is the issue.

Recommend starting over and do just the no power, full flap stall.  That is what I did and the AOA tone warning is amazingly accurate for landing.  I get the first few beeps right before the final pull for flair.  If I get beep before this I know I'm too slow and/or stretching the glide.

Carl

I had our RV-10 calibrated like you for about a year but finally decided the usefulness of the AoA was minimal. I recalibrated it and after several trial and error calibration attempts got it like a wanted. Now I get a few beeps here and there on long final letting me know that I am getting closer to the critical AoA but still have adequate margin. As I start pulling to decrease the decent rate the beeping starts to increase a little and ends up at a solid tone when the nose is high and I can no longer keep her flying and it just settles onto the runway. There is quite a bit of range across the onset of beeping and the full tone. Also if you are very smooth with your approach it works the best. The AoA audible feedback is delayed by about a 1/2 second best I can tell. If I have an established approach going on with a consistent rate of beeping then hit a updraft, there is a slight delay to the change in the audible feedback.

 

[Dynon]

Version 15, which will be available very shortly, will have improved AOA calibration algorithms too. The procedures are the same, but SkyView will do a better job of processing them.