Do any of you experienced pilots with AOA equipped GA or EAB aircraft have any recommendations based on the recent generation of AOA indicators that have recently come onto the market ? There was a previous thread covering the CYA-100 unit, and although the price is great, I personally have not particularly warmed up to the unit. It looks to be a well designed, nicely constructed piece of engineering, but the ergonomics of the display do not quite do it for me. YMMV.

http://www.backcountrypilot.org/forum/a ... 5?start=40 CYA-100

There have been some beautifully made videos describing the latest collection of Angle of Attack indicators. Two of the more easy to understand units, IMHO, include the ICON and Bendix KLR10. Here are two more links.

http://www.youtube.com/watch?feature=pl ... wlvpJLcf-A Icon

http://www.youtube.com/watch?v=maEmTsWOSvc&html5=1 Bendix KLR10

More than price, I happen to be very interested in the quick to read, easy to understand ergonomics of a unit. My preference is for an absolutely no-brainer display when things get dicey or distractions are at a max. I also think a heated? unit sensor that is tolerant to possible unexpected icing would be a good thing.

So, are any of you folks currently in build considering a particular AOA model, and if so which one and why have you selected that unit. If you have one, why did you pick what you did and would you do so again?

Finally, as a quick post edit here, this is an interesting pro/con discussion on AOA indicators. I found the many comments at the end of the article particularly interesting.

http://airfactsjournal.com/2013/08/angl ... acle-cure/

You'll see that I have quite a few comments in that Air Facts Journal article. I'm totally sold on having an AOA indicator, and I use mine all of the time. I've had it for 4 years and approximately 250 hours.

As for the ideal display, I wish mine were lit. That would be the advantage of one which uses lighting rather than just a needle position to display the AOA. Mine's plenty visible in the daytime or in the pre-dawn and dusk hours, but if I didn't have a Mic-Light on my boom mike, it would be hard to see in the dark. So if I were to ever have one installed on another airplane, I'd opt for a lit display.

A secondary reason for going with a lit display is that most of them are easier to calibrate. A mechanical one like mine requires several flights to get the probe adjusted correctly, whereas the electronic ones use computer magic to fine tune the calibration.

But as for what sort of display is best, I don't think it matters. Use it for one landing, and you will know what its display tells you. Whether it's analog, round, horizontal, vertical, or "legacy", it really doesn't matter, so long as you know what it's telling you. I'd stay away from a purely black and white display--most are color coded, anyway, and that's much preferable.

Here's the easy part: assuming that it has been properly calibrated, the standard colors tell you this:
Green = cruising
Yellow = slowing to approach speed
Red = getting too slow

The "alpha angle" is the demarcation between yellow and red. Some displays use blue to emphasize that
spot, and that's typically the color of the "donut" on the "legacy" type display. The "alpha angle" is that angle of attack at which you will still have full control of all control surfaces. As you slow into the red, the ailerons and elevators start requiring more input, as they are getting mushy. Stall typically will be at the very bottom of the red.

If it's calm, I'll use the "alpha angle" as my approach speed. If it's gusty, I fly a bit faster, so that the needle is into the yellow, between the "alpha angle" and halfway into the yellow. That's still a lot slower than book speeds, unless the airplane is at full gross. For instance, Saturday it was dead calm--well, a 3 knot wind from the north--as I landed on 9 at GXY. My load was just me at 195, my Golden at 70, my survival kit at 40, and 1/3 tanks, so I was well under gross. At the "alpha angle", my IAS showed 2 needles' width less than 60 mph (52 knots), so I nailed the IAS at 60 mph. That makes for a really nice, easy landing and a short rollout without any braking. If I was seeking an even shorter rollout, of course I could have slowed more.

If I ever trade off my airplane, I will opt for a lit AOA indicator in the new one--it would be worth the extra cost. Since that's pretty unlikely, I'll just be satisfied that my mechanical one does its job exceedingly well.

Oh, on the heated probe: I opted for that, too. I test it whenever I'm about to go IFR, just like I test the heated pitot. But I've only turned it on once to prevent it from icing. With both it and the heated pitot turned on, along with all of my lights and avionics, I'm using about 3/4 of my alternator's capacity.

Cary

I have the Dynon unit, which is not stand-alone. Are you thinking of a standalone unit?

In my view - the display doesn't matter.
I only ever look at mine when I am in a steep turn & heavy & slow, just to see how much margin I have left (usually heaps!). There's really no need to actually look at it otherwise. The problem with looking at it, is you aren't watching your touchdown point on short finals when you're closest to stall.

The audio through the headset is a very very important feature, that sound is what I can depend on for precision STOL landing. Dynon does it with a beeping noise, which increases in frequency as you approach the stall AoA, eventually becoming a constant beeeeeeeeep as you're about to stall.

The benefit is, you never need to take your eyes off the threshhold on approach to the tight landing spot, which makes a big difference in challenging weather i.e. thermals, gusts, oragraphic winds. It's really impressed me.
That's my 2c

Battson wrote:I have the Dynon unit, which is not stand-alone. Are you thinking of a standalone unit?

Which Dynon do you have? I'm looking at those for my Patrol. Although, at the rate I'm going they'll probably have a couple new models by the time I'm ready. I'm am curious about how well their combo Pitot/AoA probes work.

Also, a friend of mine, who's background includes military, airline and bush flying loves having an AoA and is installing a Dynon in his current experimental. I can't wait to hear what he as to say about it once it's flying.
Thanks.

Phil

The John's Blog article is typical of the negative comments that abound on this topic. There is NO objective material in the blog. It is simply John's opinion. The telling comment is (paraphrase) "Airspeed is a good proxy for AOA most of the time". Well great. Thanks, but it's precisely the "All the time" minus "Most of the time" equation that interests me. Secondly, his opinion that another instrument in the cockpit won't help is preposterous. The Asiana accident has nothing to do with AOA in piston aircraft. It doesn't even belong in the discussion. That accident has to do with horrible training standards at Asiana. I don't know about any of you, but I'm not getting on any Asiana flights. Of course we should all pay attention to our stick and rudder skills. That stands to reason in any airplane one could imagine. But would one be able to land an airplane without a VSI? Of course. I never look at the VSI in landing mode but I'm not going to take it out of the airplane. Can you land an airplane without an airspeed indicator. Yup. Any idiot can do it if I can. Can somebody tell me the HARM caused by an AOA in the cockpit?

What in the world is this "fear of information" that surfaces in these discussions? That's what it seems like to me. Fear; or worse. Perhaps I'm wrong, I often am. I've never used an AOA but I would sure like to try it in a downwind landing. I don't often make my spot when landing the wrong way. I've always used the "Bug on the Windshield" glide slope indicator. You can spot problems on downwind! But it has limited usefulness if you don't know your height above ground and you are trying to set up for an emergency landing. Perhaps we should talk about those issues sometime.

$.02 I know, and probably worth even less.

Bear_Builder wrote:Which Dynon do you have? I'm looking at those for my Patrol. Although, at the rate I'm going they'll probably have a couple new models by the time I'm ready. I'm am curious about how well their combo Pitot/AoA probes work.

I think software works the same in any of their EFIS products.
I am using the AoA/Pitot, seems to be very reliable and consistent. I have the full length boom mount. I do make a point of keeping a pitot cover on it during Mason Wasp season!

FAA Clears Path for Angle of Attack Indicator Installation
Earlier this month, the FAA took an important step to help improve GA safety by rolling out a more simplified set of design approval requirements for angle of attack (AOA) indicators. AOA devices can be added to small planes to supplement airspeed indicators and stall warning systems, alerting pilots of a low airspeed condition before a dangerous aerodynamic stall occurs, especially during takeoff and landing.
Under the new policy, manufacturers must build the AOA indicator system according to standards from the American Society for Testing and Materials (ATSM) and apply for FAA approval for the design via a letter certifying that the equipment meets ATSM standards and was produced under required quality systems. The FAA’s Chicago Aircraft Certification Office will process all applications to ensure consistent interpretation of the policy.
The FAA believes this streamlined policy may serve as a prototype for production approval and installation of other add-on aircraft systems in the future. For more information as well as a link to the policy document, go to http://go.usa.gov/BVZm.

When I started this thread it was with the intention of asking for specific AOA product and model recommendations. I suppose the title could also be interpreted as asking whether or not to recommend an AOA period.

For me, personally the issue is settled; I want one. I am reminded of people who put an "X" on a screen door so they don't run into it or so that animals can avoid damaging the screen. Likewise, I personally see an AOA as an extra tool for that one time when I might not be executing 100 %.. There is an old Chinese saying that even monkeys fall from trees. Perhaps even the best stick out there will occasionally experience a distraction or misjudge something, and the AOA might be there to help save the bacon so to so peak. I have a great respect for UNK UNKS..also known as Unknown Unknowns. .

I suppose those of you who have say never run into a glass or screen door,can be excused. For many of the rest of us who welcome a little extra help, an AOA might be something to consider. YMMV.

How good is the technology with the aircraft pulling G?

Ideally wings should produce a nice 'burble' feedback close to critical AofA - you get this in some aircraft, for example the Slingsby Firefly. The DH Vampire and Vixen also had a reputation for giving good feedback. Under a G load you were sensitised not to pull through the 'burble' unless you were planning an unintentional flick roll.

Conversely it would be fun to check the readings at zero G in a stall turn.

The other scenario is how helpful the indicator is with gust load conditions - here a peak reading might be useful to build in a more accurate safety margin.

It doesn't matter whether the airplane is "pulling Gs"; it only matters what the angle of attack is while it's doing that. In turbulence, since the angle of attack varies constantly with each bump, the AOA indicator will bobble around, too. Again, I don't think what type of indicator makes any difference.

I can tell you in smooth air, that as I increase bank in a level turn and thereby increase both angle of attack and Gs, the needle gradually moves down scale, just like it does as I increase angle of attack in level flight.

There's nothing magic about it, and it can't be "fooled" by doing various maneuvers. It simply reads angle of attack, fairly accurately, regardless of the display which is used.

This discussion does raise one additional point: The mechanical versions like mine don't provide any audio clues, and that would be a valuable benefit to the electronic displays, in addition to being able to see them at night. Having mine in my peripheral vision during an approach minimizes the need for audio clues, but it would still be nice to have.

If any naysayers are in the Fort Collins/Greeley area, I'd be happy to take you up so you can see for yourselves.

Cary

I see Belite just introduced an AoA. I've got one of their fuel gauges in my Challenger, and it's a slick little unit. It was very easy to install and calibrate. First aircraft fuel gauge I've ever had that was accurate. I may have to get their AoA for the Challenger too.

As for whether or not it's needed? Well ultralights were flown for years with no instruments at all. And I've trained for instrument failures. But nearly every year in Alaska a Cub pilot dies in a "Moose Turn Stall", Some of these guys had decades of experience and were very competent stick and rudder pilots. If they can die due to a laps of attention, then I sure as hell can too. Anything that'll help warn me that I'm getting into the danger zone is worth the money to me.

I've already had one scare myself. I was approaching a steep mountain side to check out some Dall Sheep. When I realized they were just patches of snow, I rolled into a turn away from the mountain, and the stall buzzer in my old C150 started screaming at me. I didn't actually stall, and had plenty of air under me to recover even If I had. But it was sure a wake up call for me. I'd had no clue that I'd been slowly climbing toward those "sheep", and loosing airspeed. I'm not infallible, so I'll take all the help I can get in the cockpit.

Battson wrote:

Bear_Builder wrote:Which Dynon do you have? I'm looking at those for my Patrol. Although, at the rate I'm going they'll probably have a couple new models by the time I'm ready. I'm am curious about how well their combo Pitot/AoA probes work.

I think software works the same in any of their EFIS products.
I am using the AoA/Pitot, seems to be very reliable and consistent. I have the full length boom mount. I do make a point of keeping a pitot cover on it during Mason Wasp season!

Sounds good. Thanks.

Phil

How fast do theses AoA indicators react? For instance if you are landing in really gusty conditions or hit a wind shear are they nearly instantaneous as the AoA jumps around due to relative wind? Thanks for all the great info,

Mine reacts instantaneously.

Cary

scottf wrote:How fast do theses AoA indicators react? For instance if you are landing in really gusty conditions or hit a wind shear are they nearly instantaneous as the AoA jumps around due to relative wind? Thanks for all the great info,

I landed in the worst conditions for a taildragger I have yet faced, yesterday, (about 3-4 times on the one approach), and the air pressure style of AoA reacts instantly to changes in the wind as it gusts. It gives a great indication of how close to the edge you are, in this case I needed almost 10 kts extra to beat the gust spread.

RE: flaps up after landings, that helps a lot too with sh*tty conditions... flying on the ground is no fun...
Gusty >25kt crosswinds suck.

Scotty, yesterday I made the mistake of going for a joy ride with a front moving down from the north. It was nearly calm on the ground, and in the air it wasn't bad at all. I flew around for just a few minutes east of Greeley and started turning around, when all of a sudden I was hit with moderate to severe turbulence--the first time in many years I've had that happen. While I wasn't focusing on the AOA indicator (mostly I was trying to stay under control, not entirely successfully), I noticed it reacted to every bump.

At one point as the airplane was being tossed one way while I had the yoke full lock the other way, I saw that the needle had gone to the bottom of the red and the stall warner went off at about the same time. But again, I was a whole lot more concerned with maintaining a semblance of control than watching the AOA indicator--and hoping that what I was experiencing in the air wouldn't be what was happening on the ground. As it happened, the wind was blowing pretty hard, but not gusty, at ground level, so the landing was easy.

Cary