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Octane for 912 ULS

in General Tech Discussion 10 years ago

  • Re: Octane for 912 ULS

    by » 10 years ago

    We can't get 91 octane here in Alaska, 90 is the highest. For the 914 I was thinking of running 3/4 90 octane and 1/4 100LL. Any thoughts on mixing?
      
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  • Re: Octane for 912 ULS

    by » 10 years ago

    mixing any ratio of avgas to autogas is OK. It does increase the octane and stabilizes the fuel.
    From some fuel expert:
    Avgas has a MON of about 104
    regular autogas has a MON of 82.5
    If you multiply the MON by the percentage of fuel you can get an idea of the octane.
    50/50 mix: (104 x 0.5) + (82.5 x 0.5) = 93.25 MON
    75% regular autogas mixed with 25% Avgas: (104 x 0.25) + (82.5 x 0.75) = 87.8 MON
    Sorry I don't know how to convert to AKI as we are missing the RON factor.
      
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  • Re: Octane for 912 ULS

    by » 10 years ago

    When we mix 87 oct (AKI) with 100LL we mix it no less than a 50/50 blend. 50% of 87 with 50% of 100LL should be 91 oct (AKI)

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

      
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  • Re: Octane for 912 ULS

    by » 10 years ago

    I really appreciate all the comments. I flew back from Honolulu direct to Kona today... a lot of water underneath. Again, while it was windy as hell--turbulent, the engine seemed to just hum along all day on 89octane ( unleaded; no ethanol ).

    Still........, based upon excellent input, I decided today that in ALL future flying I will mix about 1/2half 92 octane ( w/ 10% ethanol ) with 1/2half 89 octane ( w/o ethanol ). This will produce 90.5 octane, with only 5% ethanol, surely a satisfactory overall octane and significant improvement over the pure 89 octant I have been using since buying my CTLS on the mainland, shipping it to Hawaii almost two years ago, and flying all along through-out the islands w/o any adverse efects ( on 89octane ) ever since.

    Thanks to all.

    Scott Church
    Kona,Hawaii
      
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  • Re: Octane for 912 ULS

    by » 10 years ago

    I am fairly new to the Rotax. I have a 912ULS in my RV12. My question is: How do I know if I have a clutch in the reduction gear? If anyone can help I would appreciate it. Thanks Rod
      
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