Aerodynamic term I had not heard of until now

Discussion in 'Pilot Training' started by AggieMike88, Jan 28, 2019.

  1. AggieMike88

    AggieMike88 Touchdown! Greaser!

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    The original "I don't know it all" of aviation.
    Studying for CFI Written.... New word is "Phugoid"

    Wikipedia explanation: https://en.wikipedia.org/wiki/Phugoid

    A phugoid or fugoid /ˈfjuːɡɔɪd/ is an aircraft motion in which the vehicle pitches up and climbs, and then pitches down and descends, accompanied by speeding up and slowing down as it goes "downhill" and "uphill". This is one of the basic flight dynamics modes of an aircraft (others include short period, dutch roll, and spiral divergence), and a classic example of a negative feedback system.​


    Test question was

    If the airspeed increases and decreases during longitudinal Phugoid oscillations, the aircraft

    ... is maintaining a nearly constant angle of attack​
     
  2. Ryanb

    Ryanb Final Approach PoA Supporter

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    hmm can’t say I have either.
     
  3. CC268

    CC268 Final Approach

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    Yep the phugoid mode. It is a dynamic mode (dynamic stability). Learned about it in my Aerosytem Dynamics class.

    Phugoid Mode
    Short Period Mode
    Dutch Roll
    etc

    It's been several years now, but I remember having to calculate stability matrices, eigen vectors, etc, which I guess mathematically described the dynamic stability of an aircraft. I don't remember much anymore though :(

    The PHAK doesn't discuss Phugoid or Short Period modes. At least not in Chapter 5.
     
    Last edited: Jan 28, 2019
  4. Stingray Don

    Stingray Don En-Route

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    I think I had a phugoid once. Fortunately, the doctor was able to surgically remove it. :D
     
    Last edited: Jan 28, 2019
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  5. kyleb

    kyleb En-Route PoA Supporter

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    Drake the Outlaw
    That was the "Scientificy" word Jim Campbell used in every flight review of every aircraft he tested or claimed to test. I got bored with it 20+ years ago.
     
  6. Tantalum

    Tantalum En-Route

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  7. PaulS

    PaulS Final Approach

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    It's an engineering term that does not belong on a pilot's exam in my opinion. I was flustered with the IR written's obtuse questions, especially with the questions that had more than one correct answer where you had to select the answer that was "more correct".... smh. The material is difficult enough without trying to get slick with the questions.
     
  8. AggieMike88

    AggieMike88 Touchdown! Greaser!

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    The original "I don't know it all" of aviation.
    At least I haven't yet seen "ahenway"
     
  9. maj75

    maj75 Pre-Flight

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    About 8lbs...
     
  10. PaulS

    PaulS Final Approach

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    What's ahenway??? ;) It's pretty damn close though.
     
  11. kath

    kath Line Up and Wait

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    Like you, I had never heard of it before I started studying for the CFI written.
     
  12. AggieMike88

    AggieMike88 Touchdown! Greaser!

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    The original "I don't know it all" of aviation.
    See Maj75's response.

    A good joke to pull on someone when they aren't paying attention.
     
  13. AggieMike88

    AggieMike88 Touchdown! Greaser!

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    The original "I don't know it all" of aviation.
    Might make for an interesting bumper sticker....

    "Ask me about my Phugoid"

    "I'm proud of my honors Phugoid"

    "Don't laugh, it's Phugoid"​
     
  14. midwestpa24

    midwestpa24 Cleared for Takeoff

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    A CFI candidate is supposed to have a more in-depth level of knowledge than the average pilot, hence this question appearing on the CFI written.

    That being said even the PPL writtens have gotten a little ridiculous with their questions. I have had several students recently coming back scratching their head on certain questions with multiple correct answers, or calculation questions where after doing all the math we came up with 120 for example, but the given answers are 118 and 122. Splitting hairs when having to use performance grid charts or sectionals.
     
  15. drjcustis

    drjcustis Pre-takeoff checklist

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    I had a Cessna Cardinal that had significant, persistent phugoid oscillations. Bothered me for 2 years before a CFI taught me the term and how to handle them. Flying became much easier.


    Sent from my iPad using Tapatalk
     
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  16. maj75

    maj75 Pre-Flight

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    “My Phugoid can beat up your Honor Roll student.”
     
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  17. dtuuri

    dtuuri En-Route

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    It's on Pg 3-11. Personally, I used to demonstrate them to students in lesson two or three.
     
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  18. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    Hmmm. Go read up on United 232...
     
  19. Bill Watson

    Bill Watson Pattern Altitude

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    ...and the difference between that p thing and PIOs is?


    Sent from my iPad using Tapatalk Pro
     
  20. AggieMike88

    AggieMike88 Touchdown! Greaser!

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    The original "I don't know it all" of aviation.
    Maybe redo this well known SNL sketch...

    [​IMG]

    And substitute Phugoid for that.... other word

    Bob: Hey guys!

    Jack: Hey, Bob! Hey, your Phugoid looks great today.

    Bob: Thanks, Jack. Yours too.

    Ted: Hey, Bob.

    Bob: Hey, Ted. How’s your Phugoid?

    Ted: Not bad.

    Bob: Good. Hey, I’d like you guys to meet Doug.

    Jack: Hey, Doug.

    Doug: Hey, guys.

    Jack: Hey, pretty small Phugoid there, Doug.

    Doug: Huh?

    Ted: Yeah. You could pick a lock with that Phugoid.​
     
  21. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser! PoA Supporter

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    ha, used the word not 2 days ago.
     
  22. kyleb

    kyleb En-Route PoA Supporter

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    Drake the Outlaw
    A PIO is you (the pilot) destabilizing things or amplifying the oscillations.

    The phugoid is a measure of the airplane's own ability to damp out off-speed or off-pitch excursions (generally measured from when a steady state condition was disturbed). So, you're cruising along all trimmed out and you pull the yoke to a pitch-up which costs the airplane 10 knots. How many climb/descent cycles will it take until the airplane returns to steady-state?
     
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  23. Bill Jennings

    Bill Jennings Touchdown! Greaser! PoA Supporter

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    Mucinex. Clears that phugoid right up!
     
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  24. benyflyguy

    benyflyguy Pattern Altitude

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    Thought you could just get away with some penicillin for that...
     
  25. Greg Bockelman

    Greg Bockelman Administrator Management Council Member

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    Yeah. That was the first time I heard the term.
     
  26. PaulS

    PaulS Final Approach

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    Lol, I was being your straight man.
     
  27. nauga

    nauga Pattern Altitude PoA Supporter

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    [​IMG]

    Nauga,
    and the reason your slick airplane is a b***h to trim in cruise
     
  28. tawood

    tawood Pattern Altitude

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    So is asking, "You got any updoc?"
     
  29. Walboy

    Walboy Cleared for Takeoff

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  30. Ryanb

    Ryanb Final Approach PoA Supporter

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    What’s up doc???

    :)
     
  31. PaulS

    PaulS Final Approach

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    Did you look under there?
     
  32. bluesideup

    bluesideup Pre-takeoff checklist

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    Hi everyone.
    Some of you guys have too much free time on your hands, but it can be fun to read.
    Phugoid / slow oscillations are very likely the one things that we, pilots, encounter more often that anything in flying, and never really pay attention to it. Every time you level off, from climbs, descents.. there is this oscillation that occurs until the acft stabilizes / settles.
    You can demonstrate it by trimming the acft and pitch up, pull up on the stick, and let go, observe, how the acft will oscillate, nose up, down, for a while and eventually stabilize. That also occurs when you get a gust, and or other external factors affecting the steady state the acft.
     
  33. Clip4

    Clip4 En-Route

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    I teach 3 large ground school classes a year. The written test has changed a lot and continues to expand the topics. I blame the FAA’s decision to let the Embury Riddle type schools to influence the bank of test questions. While outdated questions have been purged, other questions beyond the knowledge required for a private pilot have been included.
     
  34. luvflyin

    luvflyin Final Approach

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    Ah, the good ol' Cardinal Crowhop
     
  35. NoHeat

    NoHeat En-Route

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    It explains the curveball pitch, in baseball.

    Not sure what it has to do with aviation.
     
  36. midwestpa24

    midwestpa24 Cleared for Takeoff

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    One of my recent ones recalled several questions on constant speed propeller operations. It's been nearly 20 years since I took a PPL written, and I don't recall that being on there. I thought that was saved for complex/high performance endorsements.
     
  37. Clip4

    Clip4 En-Route

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    Not only questions on the CS operations, but the engine performance chart is for CS. Also there is a Vg diagram.
     
  38. midwestpa24

    midwestpa24 Cleared for Takeoff

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    Next they will be asking them about tailwheels! Oh the humanity!
     
  39. mondtster

    mondtster En-Route

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    The CS prop questions on the private pilot airplane test have been there for at least 10 years now. I've always assumed they were included because no endorsement is needed to fly an airplane with a CS prop so a brand new private pilot would be qualified to fly it.
     
  40. Hank S

    Hank S En-Route

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    I've flown a square tail 172 with a manifold pressure gage. It was weird not having a prop control or gear lever . . . .