Modern AOA disappointmentad

[201er]

At Oshkosh, I saw a few vendors with modern AOA indicators. Nice heads up displays and audio alerts but an overall disappointment. They're selling it as nothing more than a glorified stall warning. All indications are related to stall prevention and AOA relative to stall. Green is further from stall, yellow closer, red very close. The big dot or target pertains to 1.3 Vso.

The lighted digital display does a poor job illustrating rate of change. The old analog safe flight unit in my plane has a simple needle. Not only does it illustrate relative AOA, but you can also see the rate the needle moves to predict AOA changes. A good use of this is when rolling into a steep bank, you can predict if AOA will be suitable at the bank angle you plan to stop the roll at. Just because angle of attack is increasing doesn't mean there's need for alarm when you plan to roll out in just ten more degrees. 

However, there is so much more value to a proper AOA than what I have seen from these vendors. AOA isn't just about stall or approach speed. It also relates to optimal performance as it relates to Vx, Vy, and best glide. This is extremely helpful in the turn where it is complicated to derive airspeed as it relates to weight, configuration, and bank angle. For example, you takeoff from an uphill runway and pitch for Vx. There is a mountain ahead and rising terrain so you need to hold Vx into your crosswind turn. With my AOA, I can pitch for Vx AOA on the departure climb and match the reduction in my pitch attitude in the turn to match the increase in required AOA in the turn to maintain Vx throughout the bank range. As bank angle and load increase, I can progressively lower the pitch attitude to maintain Vx in all parts of he turn. Although climb rate will suffer in the turn (due to the horizontal component of lift and increased load), I will still be able to maintain the best angle of climb attainable by maintaining Vx AOA. Flying Vx speed into an increasing bank is not only dangerously close to stall, it is also behind the power curve and will hurt climb performance further. The resultant poor climb may contribute to many panicked pull backs that lead to turning departure stalls.

Likewise I can optimize Vy climb and maintain best glide angle of attack in simulated engine out practice. Weight and speed will vary, but the AOA to maintain Vx, Vy, 1.3vso, and best glide remain the same. Even in the turns, without knowing the corresponding speeds in the turn, I can get optimal performance. So it's not just about avoiding stalls. It can help me avoid running into terrain by having the most efficient possible climb angle at all times.

It is a crying shame that some or most of the new AOA devices on the market are being sold as a stylish stall warning and not the fantastically useful device that it can be. I fault the instructors and old school pilot culture that thinks in terms of airspeed and not in terms of angle of attack. A change of culture is more important than just a change of devices. Using angle of attack indicators can do more than just prevent stalls, it can also help us maximize the performance of our craft for other forms of safety as well. It can help us think more fundamentally about how we fly and lead to better decision making. 

Edited July 31, 2016 by 201er

[jetdriven]

I wish they would sell a real AOA instead of this pitot tube with a hole near the bottom.  Is that thing  calibrated with flaps up or flaps down? How accurate is it in ALL flight regimes?

here's my deal, if I'm going to fly the airplane near the ragged edge like my life depends on it, and it does in this circmstance, how accurate is it?  

Edited July 31, 2016 by jetdriven

[chrisk]

I think the "CYA" AOA is real, but it looks like it was made in someones basement.  http://www.aircraftspruce.com/catalog/inpages/aoacya100.php

And for Mike, I admire you passion on this topic. Sounds like an opportunity.  I'd love to see a professional video on the AOPA (or EAA) website.

 

 

 

[gsxrpilot]

I installed the CYA-100 on my former plane, 6XM, and was very happy with it. It's easy to calibrate and re-calibrate if you didn't like the way it was. It was very easy to see yourself approaching the stall at many different speeds depending on weight and bank angle. It's relatively cheap, very easy to install, and takes basically no panel space.  I'll likely install another one, when I have an airplane to put it in.

[gsengle]

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[gsengle]

Also curious if anyone went with this unit - has a heated probe version, I like the analog display, and is well priced...

http://www.liftreserve.com/

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[jetdriven]

I really like that display 

[wishboneash]

I have the CYA-100 as well and I think it's a good instrument. I just need to move it to a better location near the compass where it is more easily seen. One negative is that on the ground when there is not sufficient airflow the vane may be in a weird position and it will false alarm and I have to turn it off and remind myself to turn it on once I get moving. 

[201er]

22 minutes ago, jetdriven said:

I really like that display 

The HUD ones are really neat just not nearly as useful. Now if they'd make a digital fake analog one like that with a needle that moves across a high res display with targets for Vx, Vy, glide, etc, I would be really impressed.

 

[gsengle]

The best display I've seen seems to be proprietary to Icon...

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[DonMuncy]

I like the Icon AOA as well. I wrote and suggested they market it to others, but they apparently have better things to do.

[GeorgePerry]

17 hours ago, chrisk said:

I think the "CYA" AOA is real, but it looks like it was made in someones basement.  http://www.aircraftspruce.com/catalog/inpages/aoacya100.php

And for Mike, I admire you passion on this topic. Sounds like an opportunity.  I'd love to see a professional video on the AOPA (or EAA) website.

 

 

 

 

[PTK]

A problem that I have with these AOA gadgets for GA is the location of the sensor being on one wing. Since we can't put it on the nose would it not make more sense to have one on each wing and integrate the data somehow to present true AOA? Having it on one wing it only gives you AOA info for that wing. It says nothing about the other wing, except in coordinated flight. And if it's going to be dependent upon on say an uncoordinated base to final turn it has to be right.

Until this is addressed I have a hard time seeing the benefit of an AOA indicator in our small planes.

[gsengle]

I don't believe there is an appreciable difference wing to wing even uncoordinated to make it worth it...

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[chrisk]

3 hours ago, GeorgePerry said:

 

I liked the video, but it didn't discuss flying AOA for Vx or Vy.

[Bob_Belville]

21 hours ago, chrisk said:

I think the "CYA" AOA is real.  http://www.aircraftspruce.com/catalog/inpages/aoacya100.php

And for Mike, I admire you passion on this topic. Sounds like an opportunity.  I'd love to see a professional video on the AOPA (or EAA) website.

 

 

 

The CYA has a stack of 9 lights. I feel it gives me a lot more info that the stall horn. I mounted the display high in the pilot's panel and  calibrated the top light @ Vy and the bottom light at close to Vso. The sensor s a flying wing.

[ArtVandelay]

Visual indicators are no good, I need audio alerts, I'm not looking at the instrument panel during landings or slow flight manuevers. 

[Piloto]

5 minutes ago, teejayevans said:

Visual indicators are no good, I need audio alerts, I'm not looking at the instrument panel during landings or slow flight manuevers. 

+1 I could not figure the appeal of these gadgets when the plane already comes with a factory stall warning device plus the stall strips. Next will be white wall tires for Mooney.

José

[gsengle]

The appeal is knowing where you are in the flight envelope without hitting the stall warning. Best glide for instance, or short field approaches. People miss the point if they think it is for stall...

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[PTK]

An aoa gadget will not tell me anything more than my AS indicator in my GA pattern. Stall spins happen because the airplane was allowed to get too slow...pure and simple.

But just for kicks let's take short field ops as an example. I routinely make the first turn off of the runway at my home field which is about 1200 feet. How much shorter in feet are you folks with your ("half-ass")* AOA gadget landing? How different is your Vso you fly with your AOA from what's in your POH? And if you don't know please don't tell me that with your gadget you're extracting maximum performance out of the airplane! Note I haven't even mentioned banking yet, just a simple straight ahead stall.

*  "Half-ass" not in any negative sense but simply because you only get half the story, one wing not both!

[gsengle]

No it's because they exceeded the maximum angle of attack. I bet most stall spins are above stall airspeed but then bank too far...

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[Piloto]

1 hour ago, gsengle said:

The appeal is knowing where you are in the flight envelope without hitting the stall warning. Best glide for instance, or short field approaches. People miss the point if they think it is for stall...

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I don't think the AOA will be accurate for best glide range. AOA is not affected with gear up/down but speed does. A glider pilot friend of mine uses an application that determines GPS ground speed and descent rate for computing instant glide range at glance. The same could be integrated into a GTN-750 or a tablet.

José

[carusoam]

There are some interesting observations here.  

1) PTK-  one wing stalls before the other in an uncoordinated stall... Having a balanced sensor system would ease the amount of multi-tasking required to avoid the stall of either wing.  

  - A safety buffer keeps either wing from stalling.

  - staying coordinated keeps one wing from stalling prior to the other.

 

2) TJ- Some  people have higher skills/discipline of multi-tasking...  I once asked when was the last time people looked at the ASI on final...  It would be best to know this data all the way through the process.  I could hear crickets chirping...

 

3) Instrument scanning technique for landing is coming to light...

  - speed.  (Attitude controlled)

  - bank angle. (Based on memory of stall speed charts)

  - coordination. (Based on the ball)

  - vertical speed. (Power controlled)

  - a stabilized approach allows for not scanning all the details to touch down.  Some risk is taken by not scanning...

  - slips and skids are more of a challenge to cover. Their cross controlled nature, increased air resistance, higher energy input, etc...

 

4) How do we get critical detail while we are looking out the front window...?

  - audible stall horn/advisory

  - lights, up on the glare shield (Bennet the engineer showed his install)

  - scan out the side window for altitude above ground.  ( Long Body challenge )  

 

5) Excess energy

- long landings, caused by float.

- bounced landings, caused by not floating out a long landing.  Porpoising...

- typical of speed padding, +5, +5, +5..... Instead of doing the math in advance...

 

6) lack of energy, too much bank angle, out of coordination, are all bad...

 

It takes some practice...

  - to scan the various instruments related to landing.  

  - to always stay within the targeted flight envelope.

  - to have a nicely stabilized approach.

 

7) Some people are going to be better at managing energy than others.  

 - AOA is a great tool to help manage energy when too much or too little are equally bad, and just right is in a narrow band.

 - Some people can do the math in their heads without a lot of effort.

- Some people have memorized the tables of stall speed vs. bank angle, including worst case gross weight. Other people, not so much...

 

8) Piloto- white wall tires may work well on the icon A5...

 

Note: I have not purchased an AOA yet...

 

Observations of a PP, not a CFI....  Let me know if I missed something...

Best regards,

-a-

[201er]

1 hour ago, PTK said:

An aoa gadget will not tell me anything more than my AS indicator in my GA pattern. Stall spins happen because the airplane was allowed to get too slow...pure and simple.

But just for kicks let's take short field ops as an example. I routinely make the first turn off of the runway at my home field which is about 1200 feet. How much shorter in feet are you folks with your ("half-ass")* AOA gadget landing? How different is your Vso you fly with your AOA from what's in your POH? And if you don't know please don't tell me that with your gadget you're extracting maximum performance out of the airplane! Note I haven't even mentioned banking yet, just a simple straight ahead stall.

*  "Half-ass" not in any negative sense but simply because you only get half the story, one wing not both!

And just how many pitot tubes do you have sticking out of your ass buddy?

[PTK]

Focus and answer the questions I posed to you Mike, if you can. 

...How much shorter, in feet please, are you landing with your AOA gadget?

and ...

How different is your Vso you fly with your AOA from what's in your POH?

We'll get to banking later.