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Rich and Eco Mode at Altitude

in 912iS Technical Questions 10 years ago
Hi All. First post here (sorry if repeating any prior).

I'm just finishing a Sling 2 in Perth Australia and working on engine installation (912is Sport). I am also installing the Airmaster CSU with Warp Drive (or Whirlwind) prop - have the Warp Drive in the garage but waiting to be convinced it's better than the Whirlwind.

A question about operations at altitude. Due to this engine running in Rich mode above 97% throttle, does this mean at altitude you need to pull the throttle back slightly to get into 'Eco' mode? (i.e. you can't operate WOT in Eco mode at altitude).

If so, I would imagine with fuel flow, there is a sudden and substantial drop in consumption as you cross that <97% mark when pulling the throttle back. Is there any indication (apart from fuel flow) to show your throttle position or know at what point you are in Eco or Rich?

Not sure (at altitude) why you can't operate WOT and still be in Eco mode - wouldn't that get you the best cruise performance (all other things being equal)?

Thanks, Ian

  • Re: Rich and Eco Mode at Altitude

    by » 10 years ago

    No question. Use the air master. Usually anything under 5300 (I.e. 5200 and below) should keep you in Eco mode. Fly up close to WOT and you'll burn the extra fuel. Many times the extra few rpm isn't getting you any more real speed verses the extra fuel. There becomes a trade off between speed and fue burn. Do some in flight testing and you'll find that point.

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

      
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  • Re: Rich and Eco Mode at Altitude

    by » 10 years ago

    You can use BUDS to find 97% throttle position and make a mark on your throttle.
    The Stock Flight Systems EMU displays the throttle position and where to set your throttle for the best start-up configuration.
      
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  • Re: Rich and Eco Mode at Altitude

    by » 10 years ago

    Thanks for the replies. Interesting.

    So it does appear the physical position of the throttle needs to be no greater than 97% (regardless of the RPM setting) to achieve ECO mode.

    I'm not putting in the Stock Flite system - I can get most things on the Garmin G3x Touch system that I need, except for throttle position and there is only so much one can spend on panels! I do understand the Stock gives you the required throttle position for start, however I reckon after a few starts I'll have that sorted.

    I guess - in operation - as well as marking the throttle position using BUDS, you could slowly ease back the throttle once cruising and keep an eye on the fuel flow until it sees a marked drop (a bit like leaning an older style engine slowly with EGT etc).
      
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  • Re: Rich and Eco Mode at Altitude

    by » 10 years ago

    sure, you can do that. also watch the EGTs; they will rise when you go into ECO.
      
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  • Re: Rich and Eco Mode at Altitude

    by » 10 years ago

    Hi Ian,
    I am also using a Garmin G3X Touch with my 912iS install. I asked G3Xpert about adding the throttle position to the G3X features. He (Steve) said it might be something they would add in the future software updates if there was enough interest. So please make a request to them. Maybe we could get this added if enough of us apply pressure.
    Regards,
    Joe Harrington
      
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