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912UL vibrations...

in 912 / 914 Technical Questions 12 years ago

  • Re: 912UL vibrations...

    by » 12 years ago

    Hi Andy,

    I'm glad it worked out and was more or less a simple fix.
    I highly recommend that carbs be synced at every 100 hr inspection. They will usually be off. It may be a small amount, but then syncing them is much easier when you keep up on them. The one thing I would also check and is check each blade on the prop and make sure the pitch is the same on each blade. I can't even count the number of times someone comes in for an inspection and I throw a prop protractor on the blades and find them any where from 1/4 - 2 degrees out of pitch from each other. I find them like this on experimental and right from a factory built plane. It only takes a couple of minutes, it's easy to do and will definitely help cure vibration issues. Most people just assume the blades are all equal, don't assume. You can use a prop protractor or just a digital level.

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

      
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  • Re: 912UL vibrations...

    by » 12 years ago

    Thanks Roger. My Ivo Medium 74" has a difference of 0.1 ° between the blades and the tracking difference is 1/8". In other words, nothing to lay awake at night for. My 912 is mounted on 4 medium lord mounts on what I call a "bench mount". I understand that a "ringmount" is absorbing the vibrations somewhat better than the "bench mount". Whats your take on that? The "ring mount" set-up, like on the Evektors Sport Star, is of course more money. But the Sport Star is however the most quiet installation I have ever encountered.

    Andy
      
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  • Re: 912UL vibrations...

    by » 12 years ago

    Hi Andy,

    Sometimes vibration issues become very subjective. What is a lot of vibration for one person is nothing to another. Yours may be perfectly normal now. I threw the prop pitch check in because some miss that part. To be perfectly honest I don't know which mount would be better over the other, but I know they have been mounted several ways over the many years the 912 has been around.

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

      
    Report
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