Surprising fuel performance

Discussion in 'Flight Following' started by C_Parker, Jun 10, 2019.

  1. C_Parker

    C_Parker Pre-takeoff checklist

    Joined:
    Mar 11, 2019
    Messages:
    113
    Display Name:

    Display name:
    x
    I've been getting surprisingly good fuel performance from my 182. I'm wondering if you guys are getting similar results or if there may actually be some issue.

    I tend to pull back while cruising because I'm typically sight seeing. I cruise at 18" and 2300 RPM. I'm taking off at 5-6k DA and cruising between 7-11k feet MSL.

    I hand calculated 9.0GPH and 11.2MPG (statute miles). I feel like that's pretty good for the average track log speed of 135MPH. This is in a stock 1963 182F without wheel pants or any mods.
     
  2. dmspilot

    dmspilot En-Route

    Joined:
    Oct 20, 2006
    Messages:
    3,633
    Display Name:

    Display name:
    Display name:
    18" is nothing. 9gph is not surprising. Sounds about right to me.
     
    Katamarino likes this.
  3. pigpenracing

    pigpenracing Pattern Altitude

    Joined:
    Feb 8, 2012
    Messages:
    2,326
    Location:
    Brenham Tx
    Display Name:

    Display name:
    pigpen
    Right.... That engine isn't making any power at 18" and 2300... It shouldn't burn any fuel.
    I like my engines running up higher... I personally wouldn't lug it down that low. It is all opinion though.
     
  4. C_Parker

    C_Parker Pre-takeoff checklist

    Joined:
    Mar 11, 2019
    Messages:
    113
    Display Name:

    Display name:
    x
    I should have prefaced this with the POH data which claims 10.5GPH at those same conditions. Also keep in mind that at my DA's 18" can be full throttle at cruising altitude.
     
    Last edited: Jun 10, 2019
    benyflyguy likes this.
  5. EdFred

    EdFred Touchdown! Greaser! PoA Supporter

    Joined:
    Feb 25, 2005
    Messages:
    24,034
    Location:
    Michigan
    Display Name:

    Display name:
    Ed Frederick
    Can easily account for the difference by leaning.
     
  6. Jeff767

    Jeff767 Pre-takeoff checklist

    Joined:
    Jan 24, 2018
    Messages:
    122
    Display Name:

    Display name:
    Jeff767
    You need to provide a bit more data. Do you have engine monitoring? How are you leaning? It may be you are actually on the LOP side of the curve. I regularly fly a IO540 at 8.3 gallons per hour but that is about 60 degrees LOP.
     
  7. AA5Bman

    AA5Bman Pre-takeoff checklist

    Joined:
    Jun 14, 2009
    Messages:
    224
    Display Name:

    Display name:
    MB
    It sounds about right for low power lean of peak.
     
  8. Grum.Man

    Grum.Man En-Route

    Joined:
    Jul 17, 2014
    Messages:
    2,635
    Location:
    Statesville NC
    Display Name:

    Display name:
    Grum.Man
    Sounds pretty close to me if you are lop. on my io550 I get 8 gph at 15" 2300 and 8.7 at 15" 2400.
     
  9. C_Parker

    C_Parker Pre-takeoff checklist

    Joined:
    Mar 11, 2019
    Messages:
    113
    Display Name:

    Display name:
    x
    I'm definitely not LOP, I don't know that you can even get LOP on this thing. I don't even lean to a stumble and then back off, I just keep the EGT needle straight up on the gauge which has no temperature markings.
     
  10. Grum.Man

    Grum.Man En-Route

    Joined:
    Jul 17, 2014
    Messages:
    2,635
    Location:
    Statesville NC
    Display Name:

    Display name:
    Grum.Man
    What engine do you have? If you aren't lop I would think those numbers are a little low for the power setting. What does the POH say for that power?
     
  11. Jeff Oslick

    Jeff Oslick En-Route

    Joined:
    Mar 12, 2005
    Messages:
    3,879
    Location:
    Fullerton, CA
    Display Name:

    Display name:
    Jeff Oslick
    Your numbers are similar to what I've seen. At 65% or less I lean as far as it will go and still be smooth (it isn't LOP in our plane). I've seen 135 KTAS (yes, knots) at 13,000', 9.2 gph. 182Q with wheel pants.
     
  12. Lachlan

    Lachlan En-Route

    Joined:
    Sep 23, 2015
    Messages:
    3,245
    Location:
    North Creek, NY
    Display Name:

    Display name:
    Lachlan
    I’ve seen 100 knots TAS @ 3,000’ msl burning 4.5 gph in my 150. Once.
     
  13. C_Parker

    C_Parker Pre-takeoff checklist

    Joined:
    Mar 11, 2019
    Messages:
    113
    Display Name:

    Display name:
    x
    Poh says 10.5, O-470
     
  14. Grum.Man

    Grum.Man En-Route

    Joined:
    Jul 17, 2014
    Messages:
    2,635
    Location:
    Statesville NC
    Display Name:

    Display name:
    Grum.Man
    Does you CAS match book numbers? Could me a gauge that's slightly off
     
  15. alfadog

    alfadog En-Route

    Joined:
    May 3, 2010
    Messages:
    4,951
    Location:
    Miami
    Display Name:

    Display name:
    alfadog
    Someone correct me if I am wrong but I understand that the O-470 does not have great fuel distribution and you are not advised to try running it LOP.
     
  16. Matthew Rogers

    Matthew Rogers Pre-takeoff checklist

    Joined:
    Dec 1, 2017
    Messages:
    366
    Display Name:

    Display name:
    Matt R
    Your 150 goes 100 knots!! Oh, I guess mine has done that too once every blue moon. I got to make it up to your grass strip sometime soon so our 150s can chat about their fuel consumption.
     
  17. Lachlan

    Lachlan En-Route

    Joined:
    Sep 23, 2015
    Messages:
    3,245
    Location:
    North Creek, NY
    Display Name:

    Display name:
    Lachlan
    Come on up. The brewery is always open.
     

    Attached Files:

  18. Lachlan

    Lachlan En-Route

    Joined:
    Sep 23, 2015
    Messages:
    3,245
    Location:
    North Creek, NY
    Display Name:

    Display name:
    Lachlan
    First beer is on me. After that they’re free.
     

    Attached Files:

  19. AA5Bman

    AA5Bman Pre-takeoff checklist

    Joined:
    Jun 14, 2009
    Messages:
    224
    Display Name:

    Display name:
    MB
    I would still bet it’s LOP. Just because it’s carb’ed doesn’t mean it’s impossible to go LOP, just not as easy or likely. And obviously, LOP doesn’t require stumbles.

    What fuel flow does the engine stumble at? Have you verified the fuel flow is accurate but checking how much you put back in the tank against what the meter is saying?
     
  20. dmspilot

    dmspilot En-Route

    Joined:
    Oct 20, 2006
    Messages:
    3,633
    Display Name:

    Display name:
    Display name:
    Well the book may indeed say 10.5gph, but it also gives a TAS of 147mph, and he's doing 135. Maybe it's LOP and/or maybe the tach or MAP are reading too high.
     
    Grum.Man likes this.
  21. RudyP

    RudyP Line Up and Wait

    Joined:
    Nov 5, 2008
    Messages:
    922
    Location:
    San Diego, CA
    Display Name:

    Display name:
    RudyP
    I wouldn’t say that is mindblowing efficiency. I get 13-14 NMPG at 200+ KTAS dragging a bigger cabin and fixed gear through the air.
     
  22. C_Parker

    C_Parker Pre-takeoff checklist

    Joined:
    Mar 11, 2019
    Messages:
    113
    Display Name:

    Display name:
    x
    Ah, that's a good point. The MP and tach are both original Cessna relics.