AOA vs Stall Horn

TimRF79

TimRF79

Pre-takeoff checklist
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Tim
I understand the concept of angle of attack.
However, I do not understand the added benefit of an AOA in the average single engine GA aircraft?
What does the AOA do better/different than the stallhorn?
 
A good AoA indicator is a performance instrument, similar to the Airspeed indicator. want to fly at Vx or Vy or on the edge of the Stall you want an AoA indicator. It does a better job than an Airspeed indicator because it compensates for weight and G-loading which an Airspeed indicator does not.
The Stall Warning is just that a Warning, It is designed to get your attention when the Angle of attack is approaching a Critical angle. An AoA indicator may or may not have a Warning function built into it, if it does it essentially does the same thing as a Stall Warning.

Brian
CFIIG/ASEL
 
Both are good but the audible warning of the stall horn is vital. You may not be looking at the AoA but looking out for traffic and terrain.
 
But going back to my original question,
what the practical value relevance for your average GA aircraft?

I can see you want to land a jet on an aircraft carrier, you want to be right at the limit...
You want to win the STOL competition... sure

Would it help make landings smoother if you fly at a certain AOA point, versus a certain speed on final?
 
TimRF79 said:
But going back to my original question,
what the practical value relevance for your average GA aircraft?

I can see you want to land a jet on an aircraft carrier, you want to be right at the limit...
You want to win the STOL competition... sure

Would it help make landings smoother if you fly at a certain AOA point, versus a certain speed on final?
Click to expand...
Properly used, yes. Because an airplane can stall at any speed.
 
For the average GA aircraft it is likely valueless. You probably already know when the stall horn is going to sound before it does. If you make a habit of landing marginal strips or aerobatics I suspect it is very valuable indeed.
 
TimRF79 said:
But going back to my original question,
what the practical value relevance for your average GA aircraft?

I can see you want to land a jet on an aircraft carrier, you want to be right at the limit...
You want to win the STOL competition... sure

Would it help make landings smoother if you fly at a certain AOA point, versus a certain speed on final?
Click to expand...

Aoa doesn't change with airplane load, airspeed will. I'm really starting to like using Aoa on approaches.
 
An AOA allows me to fly shallow power-on approaches or steeper power-off approaches and know what the wing is doing in either profile while the view out the front is very different. Not many guys fly like that but some do. The funny thing is the STOL guys are probably more prejudiced against AOA than any pilot segment I know.

I haven't had mine for long and I'm looking forward to doing some face-bender canyon turns to see what the AOA indicates. In my Cessna I bank 50* at 70 mph with 2 notches, pull elevator, and pull full flaps in the turn. The stall horn goes from quiet to crazy instantly, but my stall horn stops squealing about 3-4 mph before the wing stalls so as long as it's squealing I'm safe. I want to see a visual display of what that maneuver does in my Cub, which has no stall indicator.
 
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...you can't suck an AoA.. I'll tell you that much!

 
My C150 squealed with delight when I kissed her!
 
I can determine the stall angle of attack for different configurations, but I can't change when a stall warning fires. I can determine approach angle of attack for different configurations and fly that angle of attack. The stall warning is of no use here. I can determine angle of attack for best L/D (in different configurations if I need/want to) and fly that instead of an airspeed that varies with weight and configuration. The stall warning is useless here. I can use angle of attack for aerobatics to determine proximity to stall regardless of g...stall horns can do this as well but much closer to stall (and invariant) and not much use for performance rather than warning.

Nauga,
who likes AOA indicators
 
How did the ubiquitous 'stall horn' become the standard instead of AoA? Is it simply because of whistling reeds are that cheap?

It seems AoA is superior in all categories
 
TimRF79 said:
But going back to my original question,
what the practical value relevance for your average GA aircraft?

I can see you want to land a jet on an aircraft carrier, you want to be right at the limit...
You want to win the STOL competition... sure

Would it help make landings smoother if you fly at a certain AOA point, versus a certain speed on final?
Click to expand...
No matter what you are doing and regardless of g load the aoa gauge shows how much margin you have above the stall. It also allows you to always be at the optimal speed for whatever you are doing
 
Snowmass said:
Both are good but the audible warning of the stall horn is vital.
Click to expand...

I wouldn't call it "vital", not in all cases, it depends on the aircraft and pilot. I haven't flown an airplane with one in about forty years, and never missed it. In other situations it might well be desirable or even vital.

Stewartb said:
The funny thing is the STOL guys are probably more prejudiced against AOA than any pilot segment I know.
Click to expand...

It might be because STOL flying is such a dynamic thing, you don't have time to look at the instruments, you're too busy flying and avoiding trees and rocks. A "stabilized approach" isn't a thing in that world.
 
Dana said:
I wouldn't call it "vital", not in all cases, it depends on the aircraft and pilot. I haven't flown an airplane with one in about forty years, and never missed it. In other situations it might well be desirable or even vital.
Click to expand...
Even though I really appreciate AOA indications in the cockpit I agree with you. I've flown with a mix of stall cueing - audible, visual, tactile...as long as there's some 'clear and unambiguous indication' of approaching stall I'm good, even if it's not screaming in my ear. Everything beyond that is a way to make it easier to maximize performance.

Nauga,
and the elephants on the wing
 
I have a mechanical LRI (Lift Reserve Indicator) and I like it a lot. I use it more than the ASI ...
 
One of my airplanes has neither an AOA or a stall warning(beyond feeling the buffeting near stall) and I have something like 1500 landings in it with no issues. The other airplane has a stall warning and I don’t do my best landings in it, but it works out fine. I’ve even landed my Son in laws Baron 58 without an AOA indicator.

All that said, whatever floats your boat.....
 
Dana said:
It might be because STOL flying is such a dynamic thing, you don't have time to look at the instruments, you're too busy flying and avoiding trees and rocks. A "stabilized approach" isn't a thing in that world.
Click to expand...

It’s a tool. No different than slats, long flaps, and big thrust. People criticize what they don’t understand. I added it because my G3X supports it for the price of a probe. Why not? On a day I’m not on my game, if it provides me some assistance? I benefit.

I doubt there’s a single instance in history where a properly installed AOA made a pilot fly worse and I’m convinced they’ve made a lot of pilots fly better.
 
Stewartb said:
I doubt there’s a single instance in history where a properly installed AOA made a pilot fly worse...
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Oh man, you dangle that in front of me like a carrot...;)

Nauga,
and the better part of valor
 
Stewartb said:
It’s a tool. No different than slats, long flaps, and big thrust. People criticize what they don’t understand. I added it because my G3X supports it for the price of a probe. Why not? On a day I’m not on my game, if it provides me some assistance? I benefit.

I doubt there’s a single instance in history where a properly installed AOA made a pilot fly worse and I’m convinced they’ve made a lot of pilots fly better.
Click to expand...

What about that 737MAX thang. Wasn’t that kinda like an AOA thingy? Probably properly installed but maybe not designed/programmed properly. And could believing in it maybe be construed as flying worse?
 
luvflyin said:
What about that 737MAX thang. Wasn’t that kinda like an AOA thingy? Probably properly installed but maybe not designed/programmed properly. And could believing in it maybe be construed as flying worse?
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That was far more than an indicator issue and didn't '[make] a pilot fly worse' outside of inability to troubleshoot and execute. It is not an indictment of AOA indicators any more than Air France 447 and Aeroperu 603 were indictments of airspeed indicators.

Nauga,
casually but not causally
 
luvflyin said:
What about that 737MAX thang. Wasn’t that kinda like an AOA thingy? Probably properly installed but maybe not designed/programmed properly. And could believing in it maybe be construed as flying worse?
Click to expand...
Didn't that boil down to 'the machine' believing it? (not the pilots). The machine was pushing the nose down for them.
 
nauga said:
That was far more than an indicator issue and didn't '[make] a pilot fly worse' outside of inability to troubleshoot and execute. It is not an indictment of AOA indicators any more than Air France 447 and Aeroperu 603 were indictments of airspeed indicators.

Nauga,
casually but not causally
Click to expand...

Yeah. Inability to troubleshoot and execute. That could be construed as worse than those with the ability to troubleshoot and execute. Be it erroneous airspeed or AOA like indications
 
exncsurfer said:
Didn't that boil down to 'the machine' believing it? (not the pilots). The machine was pushing the nose down for them.
Click to expand...

I didn’t follow it real closely to the end of the investigation. If it was unoveridable, then yeah it was the machines fault. That being said, a bad machine should not put pilots into a position to have their ability tested to that extreme
 
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Besides for real crazy stuff... strap your wings on and fly the plane, be one with her, and you will be just fine.

I took four years off of flying before I bought my Cessna 140, after flying just her for 6 months I jumped in a Skyhawk and forgot about the stall warning horn was until I was feeling for the runway... then it hit me “my old bird doesn’t have one of them new tangled contraptions.. lol
 
If you spend sixteen hundred dollars on an AOA you're gonna swear it's the greatest thing on Earth. I mean you have to, right?
 
luvflyin said:
What about that 737MAX thang. Wasn’t that kinda like an AOA thingy? Probably properly installed but maybe not designed/programmed properly. And could believing in it maybe be construed as flying worse?
Click to expand...

not really. That was a “the system designers didn’t understand what they were doing” kind of thing.

Once lost, trust is very difficult to regain. Their job was to not get it wrong and they failed horribly.
 
Here we go again...

What about the navigation? Lots of pilots flew for years with just a stopwatch and and compass. All those electronic thingys just make pilots dumber. Do we really need starters? REAL pilots don't need 'em. And speaking of that, electrical systems. Total waste of space and weight if you ask me.
 
Silvaire said:
If you spend sixteen hundred dollars on an AOA you're gonna swear it's the greatest thing on Earth. I mean you have to, right?
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I quite literally spent less than ten bucks on my AoA. The Dynon D180, which is a 15 year old EFIS, already had the capability. Adding AoA consisted of adding a sense port to the leading edge of the wing, and running a small diameter tube to the EFIS. The sense port is a pop rivet with the mandrel removed. Instant AoA. I did one flight to calibrate it. It's so much better than a stall switch. You get a progressive indication of the angle of attack as you approach the stall, with slow tones getting closer together and finally a solid tone as you're just about to stall. Makes it really nice when you're on final, or any other time you're flying slow.
 
So are there some of you that can not feel an approaching stall without a stall warning? A stall warning is great, but I’m just curious if those who have never flown a plane without one can feel it.
 
This article is pretty good for a brief overview. The big advantage? AOA indicators work at any weight. The article mentions steep turns, which is one of my primary interests. If you’re doing a steep turn in crappy vis in a canyon you’re distracted and in a flight profile where additional information is useful.

https://www.flyingmag.com/how-it-works-angle-attack-indicator/
 
MBDiagMan said:
So are there some of you that can not feel an approaching stall without a stall warning? A stall warning is great, but I’m just curious if those who have never flown a plane without one can feel it.
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You can feel it in some, in others not so much. Part 23 certified airplanes are required to have a clear and unambiguous indication of impending stall, the audio cue is necessary in some airplanes without sufficient aerodynamic cues. Outside of normal cert it can be 'anything goes'. Some airplanes have very nice aerodynamic cueing, like buffet or wing rock, in others the first unmistakable cue is an abrupt wing drop or nose slice. To directly answer your question, I have flown both types, and in some airplanes you cannot 'feel' an approaching stall without some additional artificial cueing.

Nauga,
booked
 
Snowmass said:
Both are good but the audible warning of the stall horn is vital. You may not be looking at the AoA but looking out for traffic and terrain.
Click to expand...
My AoA is linked in to my G3X and does also give an audible warning that changes the closer to stall I get. I do not have a stall horn.
 
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