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Fuel consumption AL-31F Vs F100-PW-229s?

Discussion in 'Air Force & Aviation' started by Haavarla, Sep 13, 2009.

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  1. Haavarla

    Haavarla Active Member

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    I stumbled over this when i was debating the two UB Flanker bought nd shipped to the US:


    "But for comparison sake... (to the best of my resources)

    AL-31F (as installed in early SU-27s)
    MAX Thrust: 27,557 lbs
    MIL Thrust: 17,305 lbs
    Length: 194.7"
    Max Diameter: 48.82"
    Inlet Diameter: 35.8"
    Weight: 3,373 lbs
    MAX SFC: 1.96 lb/h/lb st
    MIL SFC: 0.666 lb/h/lb st

    F100-PW-229 (As available today @ $5M each!)
    MAX Thrust: 29,100 lbs
    MIL Thrust: 17,800 lbs
    Length: 191.2"
    Max Diameter: 46.5"
    Inlet Diameter: 34.8"
    Weight: 3,795 lbs
    MAX SFC: 2.060 lb/h/lb st
    MIL SFC: 0.762 lb/h/lb st

    So while a pair of shiny new F100-PW-229s would physically fit into the engine bays of the SU-27 (almost exactly) and the -229 makes about the same power; the differences in gearbox placement would make the procedure cost prohibitive."

    The AL-31F(early version) consume less fuel over the F100-PW-229s on full mill power.
    Can anyone confirm this data?

    More data:
    Maximum dry:
    AL-31F 17,305 lb st
    Later versions 17,857 lb st

    SFC MAX thrust 1.96 lb/h/lb st
    Maximum dry:
    AL-31F 0.666 lb/h/lb st
    AL-31FP 0.67 lb/h/lb st
    AL-31FN 0.705 lb/h/lb st


    AL-31F:

    Mass Flow 247lbs/s, BPR 0.571, OPR 23.5 MAX SFC 1.96lb/h/lb st


    F100-PW-229:

    Mass Flow 254lbs/s, BPR 0.36, OPR 32.4, MAX SFC1.94 lb/h/lb st


    I do imagine the better MIL SFC has to do with the engines' respective BPR, one also has to consider the OPR. The PW-229 has LOTS more compression.

    And the fact that the F100-PW-229 has smaller fan blade diameter and higher flow mass due to more compression vs the AL-31F, would suggest that those fuel consumption data aren't to far off.

    Thanks


    Sources: [email protected]'s stuff..

    Thanks
     
  2. Duffy

    Duffy New Member

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    Yes The Specific Fuel Consumption is lower for the AL-31-F in both Mil and Burner(static) and is most likely due to the Higher Bypass ratio .59:1 as opposed to .36:1 . That_Engine_Guy is usually correct.;)
     
  3. powerslavenegi

    powerslavenegi New Member

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    Well couple of things here:

    Are those SFC figures for 'F100-PW-229' from a product sheet from P&W ? for I have not yet seen P&W divulging those details in open media.

    Secondly the F100-PW-229 is designed ground up for super cruise unlike the AL-31 family hence comparing them makes little sense as the two engines will be operating in different regimes most of the time i.e. while F100-PW-229 will mostly be operating in DRY regime without the ABs the AL-31 powered Flanker family on other hand will have to engage the ABs for going above MACH 1 so the SFC for Al-31 will go up considerably.

    All in all for a typical mission profile where an AC spends a huge portion of the flight time in subsonic regime it is obvious that AL-31 SFC numbers would be low when compared to the F100-PW-229 ; however for air superiority role where speed is the key F100-PW-229 will have lower SFC as compared to the AL-31 family throughout the supersonic regime.
     
  4. Duffy

    Duffy New Member

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    It looks like the info came from Janes . But is available from several sources. The F100-PW-229 was not designed to super cruise. By the old definition of above mach 1 with no burner it is possible for the f-16 flying clean. I would assume the same goes for the f-15 but I cant conferm.
    The PW-229 and the AL-31 are designed to fly in the same regime, but Haavarla question was if there installed in the Flanker.So the Flanker regime would be the base line.You are correct, the Pratt will have a lower SFC at higher Mach numbers. With a higher core presser and exhaust velocity. I would like to see them do this just for fun.
     
    Last edited: Sep 14, 2009
  5. Haavarla

    Haavarla Active Member

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    Yes he usually is:)

    Thx for the input.