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AOA Calibration

T

todehnal

Well Known Member
I read the instruction is the Dynon manual, but am a bit confused. It says to climb to altitude, get to a fast cruise, and to do four, 5 degree oscillations. No problem here. Then it says to do a stall, and after recovery, to press the "stall" button to record it. Then repeat in other configurations, as you like. My question is should that initial stall be a power off?? I would think so. I imagine that at a fast cruise power setting, you would get a pretty aggressive whip stall, whereas power off stalls are quite gentle in the 12. Has anyone else done this calibration??

Thanks.............Tom
 
I know with my Dynon D100 I had to due the fast cruise with the oscillations like you described and then four different stall configurations, but I don't remember the order they needed to be done in.
  • Power off stall - clean
  • power off stall - flaps down
  • power on stall - clean
  • power on stall - flaps down
Once done the unit has worked flawlessly.

NOTE: I'm not sure if the Skyview is the same!
 
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Unless you've deviated from the RV-12 S-LSA or E-LSA design, you don't have an AOA system.

The SkyView AOA calibration procedure assumes you have the Dynon Pitot/AOA probe installed. There are a few low cost do-it-yourself designs suggested in this forum, but including them during your initial build may give you an "EAB" certification instead of an E-LSA.
 
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I have Skyview and I calibrated mine a couple of months ago as described above. It was easy and has worked great since then. All power off stalls.
 
Bob Waldon - LOTS of us have AOA in the RV12 because you can easily add it for about $12 in parts. See this thread starting post 14 and continuing. http://www.vansairforce.com/community/showthread.php?t=34040

I operate off of a 1260' grass strip. AOA is great, particularly because it is audible - don't need to look down at the display. And the best calibration of it for my situation is power off full flaps.

BTW I installed the piece of 1/8 inch tubing into the ADAHRS AOA connector and ran it to the wing root before ELSA certification. Because it was easier. And at that point is just a half ounce piece of tubing with no function, similar to a pull string. Ditto for the tubing from the wing root into the area you reach by opening the stall switch cover. Again, it is less than an ounce of thin tubing. After certification I drilled the hole, installed the inflation needle, (it was later shown that a rivet like the static port rivet would work, but I like the needle) and hooked it up. Told the Skyview it had AOA, no fuss.

It would not have been difficult to do all of this after certification if you had a split rear bulkhead (which you should anyway). That thin, tough 1/8 inch tubing can just lay in the large wing rib holes, it doesn't have to feed through the snap bushings. Feed it in with a long stick.
 
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I would calibrate it full flap power off as this will give you the lowest stall AOA for any airplane and it is therefor conservative.

It would be nice if the system was smart enough to have a table for flaps up and flaps down, as flap has a big impact on stall AOA but that is more complexity than required I guess, so more things to fail.
 
+1, schrader valve adapter to beach ball + a bit of tubing for one way 1700' strip. I use a schrader valve cap to cover it in the hangar. One interesting observation, I forgot to remove the cap on one flight and was surprised that the AOA continued to work as it did before. That seems to indicate that the Dynon 180 only needs the AOA port for initial calibration!?
 
The logic in the Dynon systems is that you can do as many stalls as you want, and we will use the "deepest" stall (highest AoA) as the reference for the start of the red.

So you can choose what kind of stalls and configurations you use to calibrate.

The system does need the AoA port for sure to work! It is the difference between pitot and AoA that is the AoA measurement, so if you block the AoA you will still get response because pitot will change, but it's not really accurate.
 
Thanks for the replies guys. Bill, I did your mod during build, as I am EAB. Cheapest mod on the planet, and I can't wait to put it into action. Now that Waldo knows that he can have it in a 12, he might like one also. The small tubing and shrader valve was a piece of cake to install during the build. Sounds like a couple of power off, full flaps stalls will give me what I need.

Tom
 
RV3flier - I also cover the Shrader valve adapter with a valve cap, but I used a small piece of safety wire in that cap to attach a long yellow streamer to it. I labeled the streamer "Helium Port."
 
We calibrated the AOA on the D100 in our RV7 some time ago.

Followed the procedure.

My Bro was doing the paperwork, pressing the buttons etc and I was doing the glorious stuff.

All went well until he said - do a full power stall.....

Say again !

It says to do a full power stall Bro.

Uhhh, OK.

I do it, he screams like a girl, I say - PUSH THE BUTTON.

My word, how I was laughing........:D
 
Bill_H said:
RV3flier - I also cover the Shrader valve adapter with a valve cap, but I used a small piece of safety wire in that cap to attach a long yellow streamer to it. I labeled the streamer "Helium Port."
Click to expand...

Well, maybe using a yellow aviation type schrader cap is not enough. I may also add a streamer. It's kinda SOP that when I take off the pitot cover , I grab the AOA cap on the way to the desk. Never have, but I suppose that I could miss it.............Tom
 
Bill_H said:
Bob Waldon - LOTS of us have AOA in the RV12 because you can easily add it for about $12 in parts.
Click to expand...

Thanks for the reply, Bill H. I have no argument about the value of an AOA in RV aircraft: I have two SkyView displays in my RV-7 with dual ADAHRS and a heated pitot/AOA system and wouldn't fly IFR without it.

When I said that the RV-12 doesn't have an AOA, I was referring to a stock S-LSA or E-LSA built according to Van's RV-12 criteria.

Van designed a great RV-12 airplane, and Dynon has engineered a very reliable avionics system. The RV-12 wings are removable, hence the spinner-pitot tube design. When you start adding components in the wings outside of the Van's certified RV-12 LSA criteria (during your initial build).... you are entering the EAB realm and are on your own.
 
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A little clarification............

rswalden said:
Van designed a great RV-12 airplane, and Dynon has engineered a very reliable avionics system. The RV-12 wings are removable, hence the spinner-pitot tube design. When you start adding components outside of the Van's certified RV-12 LSA criteria.... you are entering the EAB realm and all bets are off. That's fine.... as long as you don't intend to sell your airplane as an E-LSA to an unsuspecting buyer who is hanging his bacon on your $12 of parts and improvised design.
Click to expand...

An ELSA is always an ELSA. It can never be changed to an EAB!

Yes, Mods can be done to the RV-12 after certification, but it still remains an ELSA.
 
Bob W - "all bets are off" - really?

Lets see - there are only 3 parts.
1. What is "unreliable about an expoxied-in schrader adapter? Or, if you prefer, the exact same rivet used as the static source?
2. What is "unreliable" about the standard tubing to the ADAHRS? It does go through a McMaster-Carr quick disconnect (at the wing root, for easy wing removal) designed for the purpose, and the pressure held by that disconnect is quite low, always approximately pitot pressure.
3. And what is "unreliable" about the connection back at the ADAHRS, also using a standard McMaster-Carr fitting, just like the other two connections to the ADAHRS?

"Improvised design"... really?

BTW this is not "my" design, the thread makes that clear. I say that because I don't want to take credit for what is an exceptional example of Joe Gore's making a substantial improvement to the plane at negligible cost.
 
Van's would be wise to build this into the basic RV-12 design

I realize there are a lot of great ideas on these threads for post E-LSA installation into the -12, but this "$12 AOA mod" is absolutely the best thing I've added to date. Every landing is a short field landing and the safety margin it has added in the pattern is substantial. We should get an insurance credit for having a functioning AOA system IMHO.
 
Paul LeDoux said:
I have it on good authority that Waldo is in Japan until the heat is off.

Paul:)
Click to expand...

Paul,
Greetings from Tokyo.
You are right.... I'll hide out here until the thread is closed.
By the way, I can get the AOA parts for $3 over here...
I'm also trying to find that metric crescent wrench that our RV-12 plans call for. What page was that on?
 
Bill_H said:
RV3flier - I also cover the Shrader valve adapter with a valve cap, but I used a small piece of safety wire in that cap to attach a long yellow streamer to it. I labeled the streamer "Helium Port."
Click to expand...

Been away for awhile, I should do that and soon. I did for the pitot ---
I also appreciate the response from Dynon as to why I still got an AOA indication.
 
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