AOA vs Stall Horn

Discussion in 'Flight Following' started by TimRF79, Apr 29, 2021.

  1. TimRF79

    TimRF79 Pre-takeoff checklist

    Joined:
    Dec 10, 2017
    Messages:
    315
    Location:
    Houston, TX
    Display Name:

    Display name:
    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?
     
  2. bflynn

    bflynn Final Approach

    Joined:
    Apr 24, 2012
    Messages:
    7,105
    Location:
    KRDU
    Display Name:

    Display name:
    Brian Flynn
    The AoA can tell you when you're getting closer. The stall horn just starts to chirp a little when you reach a certain AoA. It's the difference between a gauge and a warning light.
     
  3. brcase

    brcase Pattern Altitude

    Joined:
    Jun 11, 2008
    Messages:
    2,043
    Location:
    Boise, Idaho
    Display Name:

    Display name:
    Brian
    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
     
    AKBill, Shepherd, Witmo and 1 other person like this.
  4. Snowmass

    Snowmass Line Up and Wait

    Joined:
    Oct 31, 2019
    Messages:
    581
    Location:
    S.E. Arizona highlands
    Display Name:

    Display name:
    Arturo
    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.
     
  5. TimRF79

    TimRF79 Pre-takeoff checklist

    Joined:
    Dec 10, 2017
    Messages:
    315
    Location:
    Houston, TX
    Display Name:

    Display name:
    Tim
    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?
     
  6. Kenny Phillips

    Kenny Phillips En-Route

    Joined:
    Jul 29, 2018
    Messages:
    4,113
    Display Name:

    Display name:
    Kenny Phillips
    Properly used, yes. Because an airplane can stall at any speed.
     
  7. steingar

    steingar Taxi to Parking

    Joined:
    Feb 6, 2007
    Messages:
    28,226
    Location:
    Land of Savages
    Display Name:

    Display name:
    steingar
    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.
     
    Huckster79 and AeroLudite like this.
  8. PaulS

    PaulS Touchdown! Greaser!

    Joined:
    May 29, 2007
    Messages:
    11,571
    Location:
    New England
    Display Name:

    Display name:
    PaulS
    Aoa doesn't change with airplane load, airspeed will. I'm really starting to like using Aoa on approaches.
     
    DaleB likes this.
  9. Stewartb

    Stewartb Final Approach

    Joined:
    Nov 21, 2014
    Messages:
    7,146
    Location:
    Wasilla, AK
    Display Name:

    Display name:
    stewartb
    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.
     
    Last edited: Apr 29, 2021
    Huckster79 likes this.
  10. Tantalum

    Tantalum Final Approach

    Joined:
    Feb 22, 2017
    Messages:
    7,600
    Display Name:

    Display name:
    San_Diego_Pilot
    ...you can't suck an AoA.. I'll tell you that much!

     
  11. TimRF79

    TimRF79 Pre-takeoff checklist

    Joined:
    Dec 10, 2017
    Messages:
    315
    Location:
    Houston, TX
    Display Name:

    Display name:
    Tim
    One of the things I have never done and no desire to do....
     
  12. Stewartb

    Stewartb Final Approach

    Joined:
    Nov 21, 2014
    Messages:
    7,146
    Location:
    Wasilla, AK
    Display Name:

    Display name:
    stewartb
    Spiders. Mmm, tastes like chicken.
     
    Tantalum likes this.
  13. asicer

    asicer Final Approach

    Joined:
    Jan 1, 2015
    Messages:
    6,588
    Display Name:

    Display name:
    asicer
    What? Wear a safety vest? :)
     
    Tantalum likes this.
  14. TimRF79

    TimRF79 Pre-takeoff checklist

    Joined:
    Dec 10, 2017
    Messages:
    315
    Location:
    Houston, TX
    Display Name:

    Display name:
    Tim
    suck off a plane
     
  15. AeroLudite

    AeroLudite Pre-Flight

    Joined:
    May 25, 2020
    Messages:
    84
    Display Name:

    Display name:
    AeroLudite
    My C150 squealed with delight when I kissed her!
     
    wrbix likes this.
  16. nauga

    nauga Administrator Management Council Member PoA Supporter

    Joined:
    Apr 18, 2013
    Messages:
    2,827
    Location:
    Rockwood Storage Facility
    Display Name:

    Display name:
    Mantis Toboggan, MD
    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
     
    exncsurfer likes this.
  17. Tantalum

    Tantalum Final Approach

    Joined:
    Feb 22, 2017
    Messages:
    7,600
    Display Name:

    Display name:
    San_Diego_Pilot
    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
     
  18. Tarheelpilot

    Tarheelpilot Final Approach

    Joined:
    Dec 5, 2010
    Messages:
    5,235
    Location:
    North Carolina once again.
    Display Name:

    Display name:
    Tarheelpilot
    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
     
  19. Dana

    Dana Pattern Altitude

    Joined:
    Oct 19, 2016
    Messages:
    2,122
    Location:
    CT & NY
    Display Name:

    Display name:
    Dana
    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.

    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.
     
    Huckster79 likes this.
  20. nauga

    nauga Administrator Management Council Member PoA Supporter

    Joined:
    Apr 18, 2013
    Messages:
    2,827
    Location:
    Rockwood Storage Facility
    Display Name:

    Display name:
    Mantis Toboggan, MD
    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
     
  21. AggieMike88

    AggieMike88 Touchdown! Greaser! PoA Supporter

    Joined:
    Jan 13, 2010
    Messages:
    19,388
    Location:
    Denton, TX
    Display Name:

    Display name:
    The original "I don't know it all" of aviation.
    Let loose the goat!

     
  22. Daleandee

    Daleandee Cleared for Takeoff

    Joined:
    Mar 4, 2020
    Messages:
    1,453
    Display Name:

    Display name:
    Dale Andee
    I have a mechanical LRI (Lift Reserve Indicator) and I like it a lot. I use it more than the ASI ...
     
  23. MBDiagMan

    MBDiagMan En-Route

    Joined:
    May 8, 2011
    Messages:
    4,632
    Location:
    NorthEast Texas
    Display Name:

    Display name:
    Doc
    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.....
     
    Huckster79 likes this.
  24. Stewartb

    Stewartb Final Approach

    Joined:
    Nov 21, 2014
    Messages:
    7,146
    Location:
    Wasilla, AK
    Display Name:

    Display name:
    stewartb
    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.
     
  25. nauga

    nauga Administrator Management Council Member PoA Supporter

    Joined:
    Apr 18, 2013
    Messages:
    2,827
    Location:
    Rockwood Storage Facility
    Display Name:

    Display name:
    Mantis Toboggan, MD
    Oh man, you dangle that in front of me like a carrot...;)

    Nauga,
    and the better part of valor
     
  26. luvflyin

    luvflyin Touchdown! Greaser! PoA Supporter

    Joined:
    May 8, 2015
    Messages:
    10,391
    Location:
    Vancouver, WA
    Display Name:

    Display name:
    Luvflyin
    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?
     
  27. nauga

    nauga Administrator Management Council Member PoA Supporter

    Joined:
    Apr 18, 2013
    Messages:
    2,827
    Location:
    Rockwood Storage Facility
    Display Name:

    Display name:
    Mantis Toboggan, MD
    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
     
    flyer770, Tarheelpilot and DaleB like this.
  28. exncsurfer

    exncsurfer Pattern Altitude

    Joined:
    Sep 15, 2014
    Messages:
    1,937
    Location:
    NC
    Display Name:

    Display name:
    exncsurfer
    Didn't that boil down to 'the machine' believing it? (not the pilots). The machine was pushing the nose down for them.
     
    Johnvan and bobmrg like this.
  29. luvflyin

    luvflyin Touchdown! Greaser! PoA Supporter

    Joined:
    May 8, 2015
    Messages:
    10,391
    Location:
    Vancouver, WA
    Display Name:

    Display name:
    Luvflyin
    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
     
  30. luvflyin

    luvflyin Touchdown! Greaser! PoA Supporter

    Joined:
    May 8, 2015
    Messages:
    10,391
    Location:
    Vancouver, WA
    Display Name:

    Display name:
    Luvflyin
    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
     
    Last edited: Apr 29, 2021
  31. Huckster79

    Huckster79 Pattern Altitude

    Joined:
    Nov 22, 2018
    Messages:
    1,745
    Display Name:

    Display name:
    Huckster79
    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
     
    MBDiagMan likes this.
  32. Silvaire

    Silvaire En-Route

    Joined:
    Oct 10, 2012
    Messages:
    4,029
    Display Name:

    Display name:
    Silvaire
    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?
     
    MBDiagMan likes this.
  33. bflynn

    bflynn Final Approach

    Joined:
    Apr 24, 2012
    Messages:
    7,105
    Location:
    KRDU
    Display Name:

    Display name:
    Brian Flynn
    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.
     
  34. donjohnston

    donjohnston Cleared for Takeoff

    Joined:
    Aug 14, 2013
    Messages:
    1,333
    Location:
    Panama City, FL
    Display Name:

    Display name:
    Don
    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.
     
    455 Bravo Uniform and DaleB like this.
  35. DaleB

    DaleB Final Approach

    Joined:
    Aug 24, 2011
    Messages:
    5,060
    Location:
    Omaha, NE
    Display Name:

    Display name:
    DaleB
    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.
     
    exncsurfer and farangutan like this.
  36. MBDiagMan

    MBDiagMan En-Route

    Joined:
    May 8, 2011
    Messages:
    4,632
    Location:
    NorthEast Texas
    Display Name:

    Display name:
    Doc
    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.
     
  37. Chip Sylverne

    Chip Sylverne Final Approach

    Joined:
    Jun 17, 2006
    Messages:
    5,215
    Display Name:

    Display name:
    Quit with the negative waves, man.
    Engine just quit. What's best glide, RIGHT NOW?
     
  38. Stewartb

    Stewartb Final Approach

    Joined:
    Nov 21, 2014
    Messages:
    7,146
    Location:
    Wasilla, AK
    Display Name:

    Display name:
    stewartb
    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/
     
  39. nauga

    nauga Administrator Management Council Member PoA Supporter

    Joined:
    Apr 18, 2013
    Messages:
    2,827
    Location:
    Rockwood Storage Facility
    Display Name:

    Display name:
    Mantis Toboggan, MD
    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
     
  40. MtPJimB

    MtPJimB Pre-takeoff checklist

    Joined:
    Sep 29, 2010
    Messages:
    242
    Location:
    Eatonton, GA
    Display Name:

    Display name:
    RVFlyboy
    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.
     
    Stewartb likes this.