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  • Re: Fuel burn at 75% Rotax 912 & 914

    by » 10 years ago


    Just a side note,

    Prop pitch especially being over pitched will play a big part here. I have seen as much as 1 to 2 GPH difference between over pitched and correct prop pitch.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: Fuel burn at 75% Rotax 912 & 914

    by » 10 years ago


    With all i have read on this forum, running a 912 at anything less than 100 percent power is a bad Idea. Am I to rethink my ops rpm? I fly at 52 to 5500 RPM all the time. I drop to 4000 Rpm when I am decending to land regardless of how high I am. then chop the power to idle for final unless I need a little power to clear the houses. :silly:
    I would love to fly for long periods at 4ooo Rpm but I thought that was lugging the engine. It sure is smooth there though.

  • Re: Fuel burn at 75% Rotax 912 & 914

    by » 10 years ago


    Hi Jay,

    Your cruise rpm is right in the ballpark and I wouldn't change it. As for always cruising at 4000 rpm I wouldn't do it as a constant setting. Descending and a short sight seeing time is fine, just not for the life of the engine.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: Fuel burn at 75% Rotax 912 & 914

    by » 10 years ago


    i always though, going by the operators manual, approx 5100 rpm was 75% power, obviously varies with prop pitch.

    My Savannah cruises at 5150 rpm, prop is 3 blade, pitched at 21deg. fuel use is approx 18ltrs/hour

  • Re: Fuel burn at 75% Rotax 912 & 914

    by » 10 years ago


    Hi everyone.

    I can see how running reduced RPM would be "lugging" the engine if pitch was increased at the same time but I'm having difficulty understanding how this could be the case if prop pitch remained the same. How could running reduced RPM under these circumstances be harmful? I don't know of any other engine in which lower power settings are considered harmful.

    Thanks

    Peter

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