Mixture rich on approach?

Discussion in 'Flight Following' started by 455 Bravo Uniform, May 20, 2017.

  1. Timbeck2

    Timbeck2 Final Approach

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    Cessna vs Piper POH. Lean until the engine stumbles then richen it back up at all temps. The engine doesn't care if its hot or cold outside.
     
  2. CC268

    CC268 Final Approach

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    Hmm guess I will need to check my POH again...thought it said to be full rich below 3000
     
  3. Jozu

    Jozu Filing Flight Plan

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    I fly a fuel injected Mooney out of South Valley but have flown various aircraft. I always lean for altitude. I have had an engine die from running full rich on a hot day. So I learned to give the engine the mixture ratio that will make it run most efficiently. Why at take off would you want your engine to run less efficiently than it could? It is a simple matter to look at the rpms being produced to determine the mixture that is optimal.


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  4. CC268

    CC268 Final Approach

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    I totally agree...I used to lean always before takeoff and at altitude of course...then the PoA changed my mind forever
     
  5. Timbeck2

    Timbeck2 Final Approach

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    You're in Phoenix right? Here, I'm only 367' below 3000' when I'm sitting on the ground.
     
  6. CC268

    CC268 Final Approach

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    Yea deer valley is at 1500, but on a hot day could be close to that 3000 mark. Just wasn't sure if it would be better to give it that extra cooling from running mixture rich
     
  7. Jozu

    Jozu Filing Flight Plan

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    It is not a partial power take off. It is a full power take off with an optimized fuel to air mixture ratio. Full rich does not mean full power. Look at your engine performance metrics.


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  8. Checkout_my_Six

    Checkout_my_Six Final Approach

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    zactly.....full power requires the proper mixture ratio.....which is often "not" full rich mixture.
     
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  9. CC268

    CC268 Final Approach

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    I'm gonna start leaning before takeoff...if my engine burns up I'm blaming PoA forever
     
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  10. denverpilot

    denverpilot Tied Down

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    Sorry, you're PIC. You don't get to do that. You break it, you get to keep both pieces. ;)
     
  11. Checkout_my_Six

    Checkout_my_Six Final Approach

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    you should....
     
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  12. CC268

    CC268 Final Approach

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    Handling the mixture knob is too much responsibility for me
     
  13. citizen5000

    citizen5000 Ejection Handle Pulled

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    Go by the book. The book will take into account altitude etc. Play with a big fuel injected Continental for example at your peril if you do it wrong.
     
  14. Pilawt

    Pilawt Final Approach PoA Supporter

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    Taking off in a 172 at >5000' DA with the mixture knob all the way in is not an optimized mixture ratio. The engine is producing less power than it can, safely, in those conditions. That's a partial-power takeoff.

    And I think you and Checkout_My_Six misunderstood my earlier post (my inartful prose, no doubt). We have a report of a CFI at a warm-weather 4600' MSL field mandating full rich in a 172 in all flight regimes except cruise. I'm saying it should be leaned appropriately even on takeoff and climb; to arbitrarily leave it "full rich" results in power loss, among other problems.
     
    Last edited: May 21, 2017
  15. petrolero

    petrolero Pattern Altitude

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    What he said. I never ever use full rich not even at sea level.
     
  16. coloradobluesky

    coloradobluesky En-Route Gone West

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    The plane is supposed to be set up so you go full rich at full power at sealevel (density altitude sea level). One way to check is fuel flow. Fly it at sealevel (ok 500') at full rich and see if you are getting the fuel burn specified in the POH.
     
  17. MAKG1

    MAKG1 Touchdown! Greaser!

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    Taking off leaned in a 182 at sea level is not a good thing. Minimum 18 GPH at full throttle, 15 at 23 inches.
     
  18. petrolero

    petrolero Pattern Altitude

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    It's a TR182 and try 31" and 20+ gph.

    In any case leaning for peak EGT or peak RPM is not "a bad thing"


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  19. MAKG1

    MAKG1 Touchdown! Greaser!

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    And peak CHT. Don't forget that. And the limitation to not exceed 70% power leaned in the POH of many Cessna singles.

    It's irresponsible as hell to introduce turbocharged operations into a thread clearly about natural aspiration, without qualification. Do you really want some student pilot to apply your statement to a 172? THINK.
     
  20. petrolero

    petrolero Pattern Altitude

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    GFY, interweb tough guy! Who made you the arbiter of what threads are about?

    I'm sure students across America are hanging on your every word but not mine.

    Cessna 182s of many varieties are notorious for fouling plugs and leaning for taxi and takeoff prevents that. I've lost a plug in flight. Not fun.

    Also did you see the many other posts about the same thing?

    You are why I stopped posting here anyway.

    Petrolero out! Again. smfh


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  21. Skid

    Skid Pre-takeoff checklist

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    Does anyone have any links or resources about leaning and overall engine management? Having done my primary training a long time ago and just getting back into the game my leaning knowledge is basically full rich under 3000 and lean to engine roughness with three turns in above that. With everything that's been posted I feel like I'm way behind the knowledge curve! If I remember right avweb had some great articles that I'll have to dig through again.
     
    Last edited: May 21, 2017
  22. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    Yes. Look for the early Pelican's Perch articles on AvWeb. Great stuff. "Manifold Pressure Sucks!" is the best description of constant-speed prop operations I've ever seen, and I frequently point people to it.
     
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  23. Pilawt

    Pilawt Final Approach PoA Supporter

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    Here's the index to the John Deakin articles you're thinking about: https://www.avweb.com/news/pelican/182544-1.html

    Those articles mostly talk specifically about operating larger, fuel-injected engines with good balance of fuel distribution among the cylinders, and good instrumentation. But the principles are good to understand, regardless what kind of engine you have. In a smaller carbureted engine, without all-cylinder CHT/EGT information, your technique (with 3,000' density altitude as the benchmark) works about as well as any.
     
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  24. Clark1961

    Clark1961 Touchdown! Greaser!

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    A rotax is in your future...
     
  25. Tarheelpilot

    Tarheelpilot En-Route

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    Ignore mike. Read the manufacturers recommendation and follow.
     
  26. gismo

    gismo Touchdown! Greaser!

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    Most often that only applies to full power (e.g. takeoff and climb). With most airplanes there is NO altitude where proper leaning won't improve efficiency and engine longevity. A lot of misunderstanding WRT the use of the red knob stems from CFIs and flight school owners trying to keep students and renters from abusing engines. If you want to learn the science behind engine mixture management attend the live APS course or at least try the online version.
     
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  27. CC268

    CC268 Final Approach

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    I was kidding :)
     
  28. Pilawt

    Pilawt Final Approach PoA Supporter

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    Leaning on taxi ...

    Screen Shot 2017-05-21 at 9.55.10 PM.png

    :D
     
  29. korben88

    korben88 Line Up and Wait

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    My first few lessons he showed me how to lean for altitude after the run-up. Then someone burned up the valves in the 152. After that he decided to change the app on his planes.
     
  30. denverpilot

    denverpilot Tied Down

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    What was he teaching and did the student actually do it that way?

    It's nearly impossible to fly non-turbo airplanes up here without leaning for takeoff and there's no "burning up" of valves going on.
     
  31. korben88

    korben88 Line Up and Wait

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    Honestly I don't remember the specifics, just that he sent out a bulk email to everyone that said from then on he wanted full rich for takeoff, climb and decent. He also updated the checklists in the planes.
     
  32. denverpilot

    denverpilot Tied Down

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    His airplanes, his rules... but if he thinks *properly* leaning above 3000 MSL for takeoff, caused burnt valves, he's not right.

    Someone is teaching something wrong, or someone is doing something wrong, to have that happen. That's all I'm sayin'.
     
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  33. korben88

    korben88 Line Up and Wait

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    I don't remember the procedure that he taught at the time. I might have an old checklist somewhere.

    I've been considering changing CFIs.
     
  34. midlifeflyer

    midlifeflyer Touchdown! Greaser!

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    I've seen two engines quit from the mixture being too rich. Fortunately both were silk on the ground at the time, although one of them had just been cleared for takeoff.

    I agree something weird is going on if a CFI is insisting on full rich takeoffs at high density altitude due to burning engines.
     
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  35. Dr. O

    Dr. O Pattern Altitude

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    Like many others, from the entry to the pattern and right down to wheels on the ground it is flown with the mixture leaned. As I reduce throttle I automatically lean it a bit more (mixture goes richer as you close the throttle plate) This is not done by EGT, it is just pull the levers back another half inch.
    As soon as the wheels touch it gets really leaned out (blubber blubber, shake like a wet dog, passengers scream and faint)
    I have had maybe one fouled plug in the past 20 years - probably longer than that even (but then i'm not sure what I had for breakfast, eh)
    My engines make TBO (way past)

    Now, if I need to go around I will HAVE to advance the throttle to do it (I can't think of any other way to do it)
    If I am worried that I cannot remember to also advance the mixture and props, I have no business flying. A tiny delay between full throttle and full mixture is meaningless - Especially given the windmilling engine at part throttle has cooled the head temperatures significantly.
    In my case, I have levers, so everything goes forward at the same time. ymmv
     
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  36. Caramon13

    Caramon13 Pattern Altitude

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    Lotta opinions but it really only matters what the POH says.

    @CC268 I owned a Piper for a year and here in FL with sea level operations or even 2K DA's I would use full rich to start, lean aggressively for taxi, full rich takeoff. IF I was climbing above 5,000 ft I would leave it on full rich until I climbed past that and then lean because RPM would start to drop. My POH recommended AGAINST full power and anything but full rich when < 5,000 feet.

    If I was going somewhere less than 5,000 feet (which was 90 % of the time) I would use full rich until my destination altitude and lean for cruise, because for me cruise <> full power. I had a fuel flow meter so, it was easy to get the GPH target I wanted (while monitoring CHT's, no EGT in that plane).

    Landing would be full rich and I'd have it there usually at TPA. I totally disagree with anyone saying I'll just firewall it (the mixture) on the go around. When you need power to go around, you need it now. A leaned mixture (depending where you are) may NOT GIVE you full power.

    Why do you need one more thing to do on a go-around? Just push power, cleanup the plane as necessary and go. Prop and mixture should be where they need to be to give you FULL power at the moment you need it, not as you slowly increase to it.

    Just my 2 cents...
     
    Last edited: May 22, 2017
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  37. MAKG1

    MAKG1 Touchdown! Greaser!

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    I've had an engine quit in the flare at high DA, due to flooding. It wasn't full rich, either, just too rich. Probably close to 10,000 DA that day. It's a good thing I didn't need a go-around, but as it was, it was an uneventful landing. Clearing the runway, on the other hand, was a lot more difficult (especially since that airport didn't have taxiways). Flooded hot starts on an IO-360 are not fun....and there was no mechanic within 50 miles, so I really didn't want to drain the battery.
     
  38. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    Ignore Mike at your own peril.

    I'm not a big fan of the guy, but on matters of engine management, he's right.

    5,000 is pretty high to start leaning in the climb, IMO. The Mooney has an EGT gauge with a handy "Climb" range marked on it which makes leaning in the climb really easy. It's amazing how much difference it can make in performance even as low as 1500-2000 feet to keep leaning it during the climb instead of staying full rich. By 4500 feet, I'll lose a good 1/3 of my climb performance if I leave it full rich!

    It doesn't take much - Maybe a half twist of the knob every 1000 feet or so at most - but it does make a big difference in performance.

    Absolutely. The old "Don't lean below x feet" thing has bitten some people. *ALWAYS* lean for cruise, regardless of altitude.
     
  39. Caramon13

    Caramon13 Pattern Altitude

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    /agree, I had to read it twice in the POH.

    upload_2017-5-22_12-48-56.png

    Now granted, I was flying a 1965 Cherokee 180 so..I'm sure there are variations where this is NOT a good or accepted practice. Goes back to my original statement of use the POH :).
     
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  40. Checkout_my_Six

    Checkout_my_Six Final Approach

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    remember....they are referencing a "density altitude"....not AGL or MSL. Big difference folks.

    ...and regardless you can't harm your engine by over leaning when the power settings are lower than 70-75%.