sstellarv10
Well Known Member
Just about ready to install the stall warning vane in my wing and I am thinking about using the AOA system by Advanced Flight Systems instead. Is anyone using this or any other AOA system and what are your thoughts.
Van's Air Force
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AOA Stall warning systems
- Thread starter sstellarv10
- Start date
I have the Grand Rapids System.
My thoughts are I don't use it becuase I don't like to look down at the display much when on final or steep turns goofing around. They don't offer anything to mount on the glare shield so you can keep your head up and out more easily.
So if you REALLY are serious about using one, get something that you can mount in a position you can see in your field of view easly while looking outside the cockpit. Simple row of LEDs would suffice for me.
However, I like how you don't have to mount anything on the airplane to get the GRT system to work...here's how they describe it works and how to read it.
See section 2.10 Angle of Attack
http://www.grtavionics.com/File/User%20Manuals/Horizon%20User%20Rev%20C%20Feb%202009.pdf
My thoughts are I don't use it becuase I don't like to look down at the display much when on final or steep turns goofing around. They don't offer anything to mount on the glare shield so you can keep your head up and out more easily.
So if you REALLY are serious about using one, get something that you can mount in a position you can see in your field of view easly while looking outside the cockpit. Simple row of LEDs would suffice for me.
However, I like how you don't have to mount anything on the airplane to get the GRT system to work...here's how they describe it works and how to read it.
See section 2.10 Angle of Attack
http://www.grtavionics.com/File/User%20Manuals/Horizon%20User%20Rev%20C%20Feb%202009.pdf
I use the Dynon AOA in my D180 system and it works very well. I has a pictorial presentation on the Dynon screen and an audio input to the audio panel. Additionally, it can be programed to start warning at various airspeeds. Dan.
sstellarv10
Well Known Member
AOA stall warning
I'm planning a G900 EFIS, I guess I should check to see if the AOA is included with the system
I'm planning a G900 EFIS, I guess I should check to see if the AOA is included with the system
dmaib
Well Known Member
I have been flying the AFS AOA Pro for almost a year now. I have the indicator mounted in the instrument panel. I am very happy with the system and the installation and instructions were straight forward. I installed the stall warning vane early in the building process and would not do it knowing what I know now.
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sstellarv10
Well Known Member
AOA stall warning
Its nice to see it in a panel, its hard to visualize the size from just a picture, thanks Dave.
Steve Stella
#40654 Wings
N521RV reserved
Its nice to see it in a panel, its hard to visualize the size from just a picture, thanks Dave.
Steve Stella
#40654 Wings
N521RV reserved
flion
Well Known Member
I'm planning a G900 EFIS, I guess I should check to see if the AOA is included with the system
Not included. But I going with an AOA Pro, myself. For those of you who installed an AOA, what did you do with the leading edge holes for the stall vane? Just filled with a rivet or what?
David-aviator
Well Known Member
D10A - Not terribly expensive, works great
AOA is just below ASI. I like it. Got me to slow up at least 5 knots on final.
AOA is just below ASI. I like it. Got me to slow up at least 5 knots on final.
Guy Prevost
Well Known Member
I have the AOA pro displayed on my AFS EFIS. I really like it and use it for every approach.
Guy
Guy
sstellarv10
Well Known Member
Yes you fill the holes provided for the stall warning vane with two 426AD3-3's in both left and right skins.
Steve Stella
#40654 Wings
N521RV reserved
Steve Stella
#40654 Wings
N521RV reserved
doctornigel
Active Member
Is there a reason you HAVE to install the stall warning vane? Any FAR's or such? Thanks.
Ed_Wischmeyer
Well Known Member
Some theoretical thoughts
Here's a bunch of thoughts in no particular order:
* AOA is a great concept when maneuvering near the ground at low speeds. The real question is whether a visual display is appropriate when you're mostly looking outside, i.e., when you need it most. My opinion is that an aural stall warning with multiple sounds, sort of like a Cessna reed-style system, has the most potential, especially if it is calibrated to give warning of a too-slow approach that can lead to a hard landing.
* AOA can be great for maintaining optimum AOA for long range cruise or for Vy.
* I've read what I consider a lot of hype about AOA. I think that the concept has merit for some things, but , for example, AOA won't tell you when to rotate on takeoff.
* I've not read anything about how you use AOA to reduce your susceptibility to gusts on short final. There are plenty of formulae for airspeed, by comparison. Having a device with no procedures for using it and just saying "it's wonderful" is nonsense at best....
* At Boeing, many customers were excessively on the AOA bandwagon. Boeing eventually had several of its most senior and most respected engineers write an article to bring sanity to the discussion.
* Over the years, I've tried several times to write an article on AOA, but when I started asking the hard questions, vendors had trouble finding me an airplane to fly.
My opinion? I think that most of the value of AOA is hooked up to a variable sound aural alert. I like having it as a secondary indicator for Vy and optimum AOA. But, having flown a number of aircraft with no stall warning system at all, I can (and do) get by without it. And it's not clear how much operational advantage there is to holding precise AOA for Vy and long range cruise for the operations I do.
Ed Wischmeyer
(lotsa good letters go here)
Here's a bunch of thoughts in no particular order:
* AOA is a great concept when maneuvering near the ground at low speeds. The real question is whether a visual display is appropriate when you're mostly looking outside, i.e., when you need it most. My opinion is that an aural stall warning with multiple sounds, sort of like a Cessna reed-style system, has the most potential, especially if it is calibrated to give warning of a too-slow approach that can lead to a hard landing.
* AOA can be great for maintaining optimum AOA for long range cruise or for Vy.
* I've read what I consider a lot of hype about AOA. I think that the concept has merit for some things, but , for example, AOA won't tell you when to rotate on takeoff.
* I've not read anything about how you use AOA to reduce your susceptibility to gusts on short final. There are plenty of formulae for airspeed, by comparison. Having a device with no procedures for using it and just saying "it's wonderful" is nonsense at best....
* At Boeing, many customers were excessively on the AOA bandwagon. Boeing eventually had several of its most senior and most respected engineers write an article to bring sanity to the discussion.
* Over the years, I've tried several times to write an article on AOA, but when I started asking the hard questions, vendors had trouble finding me an airplane to fly.
My opinion? I think that most of the value of AOA is hooked up to a variable sound aural alert. I like having it as a secondary indicator for Vy and optimum AOA. But, having flown a number of aircraft with no stall warning system at all, I can (and do) get by without it. And it's not clear how much operational advantage there is to holding precise AOA for Vy and long range cruise for the operations I do.
Ed Wischmeyer
(lotsa good letters go here)
AOA Warning
My AOA has got my attention twice in the last year. (got Angle, Angle push in the headset). Once turning crosswind on climb out and another turning base to finial. First time had 90 indicated with a good VSI, don't know what happened but I droped the nose anyway. 2nd time was indicated at 105 in a steep bank, just unloaded it a little and it went back to in the green on the indicator. You may want to wire the audio in both headsets, mine is just in the pilots side. My son was flying from the right the first time and he did not know why I took it away from him!
My AOA has got my attention twice in the last year. (got Angle, Angle push in the headset). Once turning crosswind on climb out and another turning base to finial. First time had 90 indicated with a good VSI, don't know what happened but I droped the nose anyway. 2nd time was indicated at 105 in a steep bank, just unloaded it a little and it went back to in the green on the indicator. You may want to wire the audio in both headsets, mine is just in the pilots side. My son was flying from the right the first time and he did not know why I took it away from him!
Ed_Wischmeyer
Well Known Member
Thoughts on voice alerts
When I was at Boeing, I did research on appropriateness of voice alerts for different situations (including manned simulator trials), and based on that and other thoughts, I'd prefer a series of sounds to voice alerts for high AOA:
* The first part of a sound often is just an attention getter, and if it's a word, chances are it will get lost and will need to be repeated if it's important
* Voices can be too compelling and block more important aural information sources. (That may not be the case for a stall warning).
* You can't tell if the silence between words is a deliberate pause between words or if the causal situation has been resolved
* I've not thought of any words I'd like to hear during a stall or high AOA situation. And it's not clear to me that having "push" given as an instruction is always going to be what I want.
And it's interesting that I never heard any discussions while I was at Boeing about wanting to make stall warning be a voice alert....
Multi-tone AOA for eyes-out flying at low speeds and low altitudes? Cool! Eyes-in AOA for optimizing climb and cruise? Maybe, but don't know how much difference it would really make for my operations. Voice alerts? NO.
Ed Wischmeyer
When I was at Boeing, I did research on appropriateness of voice alerts for different situations (including manned simulator trials), and based on that and other thoughts, I'd prefer a series of sounds to voice alerts for high AOA:
* The first part of a sound often is just an attention getter, and if it's a word, chances are it will get lost and will need to be repeated if it's important
* Voices can be too compelling and block more important aural information sources. (That may not be the case for a stall warning).
* You can't tell if the silence between words is a deliberate pause between words or if the causal situation has been resolved
* I've not thought of any words I'd like to hear during a stall or high AOA situation. And it's not clear to me that having "push" given as an instruction is always going to be what I want.
And it's interesting that I never heard any discussions while I was at Boeing about wanting to make stall warning be a voice alert....
Multi-tone AOA for eyes-out flying at low speeds and low altitudes? Cool! Eyes-in AOA for optimizing climb and cruise? Maybe, but don't know how much difference it would really make for my operations. Voice alerts? NO.
Ed Wischmeyer
flion
Well Known Member
No. I'd venture to say that almost no RVs have a stall warning vane, with the exception of the -10. There is no FAR requiring it.
Regarding Ed's first comment in the first set, not all 'low-and-slow' is visual. And I can glance at an AOA as easily as I can do my regular scan while landing. Not disagreeing with the idea that an aural alert is a good idea, though.
I'm still dreaming about my RV, but the reason I plan on installing an AOA system is for a back up to the Pitot/Static system. If icing (or bugs) blocks my pitot tube then I still have an excellent way to gauge airspeed during approach and landing. On planes with large gross wt. changes the approach speed is calculated for each landing. However, the AOA will always be the same (assuming the same amount of flaps are used).
Mike S
Senior Curmudgeon
Pitot backup?????
Dynon uses extra holes in the pitot for the AOA function, if the pitot freezes up, I suspect the AOA will already be blocked too.
AFS uses a couple of very tiny holes on the wing, one top, one bottom. I expect they will also be subject to the same freezing problem as a pitot.
Bugs, who knows what they will plug up.
All that said, my buddy with an AFS 3500 absolutely loves his internal AOA,
uses it faithfully.
Dynon uses extra holes in the pitot for the AOA function, if the pitot freezes up, I suspect the AOA will already be blocked too.
AFS uses a couple of very tiny holes on the wing, one top, one bottom. I expect they will also be subject to the same freezing problem as a pitot.
Bugs, who knows what they will plug up.
All that said, my buddy with an AFS 3500 absolutely loves his internal AOA,
uses it faithfully.
Pitot backup?????
Well, I?m a fan of some type of redundancy? I don?t like singe point failures. (see I even said that twice) The planes I fly all have redundant pitot/static systems and airspeed indicators. Knowing how fast you?re going, especially slow/close to the ground, is important. I was just reading about somebody flying a RV who had a cracked pitot line going into an instrument and it was throwing off his indicated airspeed. You can?t cross check it against GPS, but AOA would give you an accurate indication of how you?re doing at approach speeds. I will have to do a lot more research, but the Advanced Systems one says ?The AOA Pro and Sport are lightweight and easy to install. There are no ugly probes to slow you down or collect ice and no moving parts to break.?
Well, I?m a fan of some type of redundancy? I don?t like singe point failures. (see I even said that twice
) The planes I fly all have redundant pitot/static systems and airspeed indicators. Knowing how fast you?re going, especially slow/close to the ground, is important. I was just reading about somebody flying a RV who had a cracked pitot line going into an instrument and it was throwing off his indicated airspeed. You can?t cross check it against GPS, but AOA would give you an accurate indication of how you?re doing at approach speeds. I will have to do a lot more research, but the Advanced Systems one says ?The AOA Pro and Sport are lightweight and easy to install. There are no ugly probes to slow you down or collect ice and no moving parts to break.?
johngoodman
Well Known Member
I wouldn't say airspeed probes are ugly - form follows function. The Dynon heated pitot/AOA is identical to most other probes in appearance and shouldn't "collect ice". It doesn't have moving parts, so why the resistance to Angle Of Attack?
It works in all phases of flight, will show you best climb, maneuvering, approach, etc. with just a glance. And yes, it will show you rotation speed in a way - it will show your wing flying when you should have already rotated. (g)
John
(yup, I'm Navy)
Rick_A
Well Known Member
Still need Pitot & Static for AFS AOA
The AFS AOA uses 4 inputs - Pitot, Static, Upper Wing pressure port & Lower Wing pressure port. It's the Upper & Lower wing ports (very tiny holes, #60 IIRC) that are being refered to as the "no ugly probes".
I have the Sport AOA and like it a lot. I mounted the LED's on the glare shield slightly offset from my direct line of sight. I've thought about moving the LED's to be more in my direct line of sight.
The AFS AOA uses 4 inputs - Pitot, Static, Upper Wing pressure port & Lower Wing pressure port. It's the Upper & Lower wing ports (very tiny holes, #60 IIRC) that are being refered to as the "no ugly probes".
I have the Sport AOA and like it a lot. I mounted the LED's on the glare shield slightly offset from my direct line of sight. I've thought about moving the LED's to be more in my direct line of sight.
David-aviator
Well Known Member
Not to be a contrarian here, Ed, but I don't follow your reasoning regarding looking outside or looking inside.
The reason stall spin accidents happen is the pilot is not aware of his airspeed until he is looking straight down and then it is too late. There is no situation in flight where a pilot can afford not to be aware of his airspeed and the only way to maintain that awareness is to have a habit pattern of checking the instrument whether it be ASI or AOA, especially down low in the traffic pattern, day or night, IFR or VFR.
The AOA is neat because it provides a reference safety margin not present with the ASI unless the pilot is aware of his gross weight and mentally recalculates the stall speed for each approach and landing. And if that information is, where ever the source, to be of any value the pilot has to look at the gauge at least momentarily during every approach and landing to be aware of it.
AOA is a proven technology and has been for a long time. The systems we have here are not all that sophisticated, but they work fine for our purposes. For example, it does not know the flap setting but if calibrated with normal landing flaps the indication is very much in the ball park. At least that's what I believe with the D10A system. Yesterday I made an approach over some trees at 61 knots with the AOA just inside the green band, it all worked out fine. Without the AOA, I would have flown it at 70 knots just to be sure of a safe margin above stall. As it was, the airplane was light and AOA had it figured correctly.
But the bottom line here is none of this information is useful if the pilot is not aware of it and that requires looking at the indicator along with the outside visual cues - like the tops of the trees and the touch down aiming point. A pilot can not afford to look inside OR outside, he needs to do both.
I rarely look at the indicator but a few times "angle angle push push" got my immediate attention. During the first few hours it kept me honest on rotation and initial few moments climbing out on take off, RV-10 does not need quite as much back pressure as a 172 During some climbing steep turns it squaks every once in a while, only time I've ever heard it on final is in the flare...I intend to keep it that way
I do plan on trying to use the indicator for approach but need to play with it up high first to know what to expect, for now my eyes are on the scan and approach. I think the glaresheild mounted indicator may be easier, the one on the EFIS just hasn't made it to my scan yet.
During some climbing steep turns it squaks every once in a while, only time I've ever heard it on final is in the flare...I intend to keep it that wayI do plan on trying to use the indicator for approach but need to play with it up high first to know what to expect, for now my eyes are on the scan and approach. I think the glaresheild mounted indicator may be easier, the one on the EFIS just hasn't made it to my scan yet.
