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Gearbox Clutch

in General Tech Discussion 10 years ago
Just out of curiosity I am wondering what purpose the clutch serves in the 912 gearbox. I know it can save an engine teardown in case of a mild prop strike, but are there any other reasons this engine comes with a clutch (its the only engine I am aware of that uses a clutched gearbox). If the only reason is to help prevent crank damage in case of a prop strike I am not sure it is worth it, considering the fairly high maintenance issues and inspections associated with the clutch. If I had a choice I probably would choose to go without the clutch and take my chances on avoiding prop strikes, and gain a simpler engine that could go 2000 hours without "major" maintenance. There must be more to it than I know; please enlighten me.

  • Re: Gearbox Clutch

    by » 10 years ago

    James,

    The maintenance is not that big of an issue considering what having a clutch can offer.

    I assume that all engine owners who are running their gearboxes without a clutch are wishing that they could have one.

    The final choice is yours, but remember that it is like ridding a motorcycle without a helmet.

    Andre'
      
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  • Re: Gearbox Clutch

    by » 10 years ago

    I guess that is my question: What does the clutch offer besides propstrike protection? Prop-strikes are actually quite rare in the aviation world.
    Is it really true: Does everyone without a clutch wish they had one?
    It seems I hear of a lot of maintenance issues on this forum involving clutch problems and wear.

    Don't get me wrong; I'm not really trying to trash the idea of a clutch, just trying to learn more about it and why Rotax is the only one offering it.
      
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  • Re: Gearbox Clutch

    by » 10 years ago

    The gearbox is a low maint. item. Get it inspected every 1000 hrs. How long does it take the average person to put on 1000 hrs and then 2000 hrs.? Unless you do something to cause an issue then they are very reliable.

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

      
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  • Re: Gearbox Clutch

    by » 10 years ago

    Primarily the clutch was required for certification to protect the crankshaft in case of a prop strike.
    It was found to have added benefits like a slight slippage at start-up.
    It is worthwhile, we even had a pusher amphib that had a severe prop strike (wheel broke off and went through the prop) but as he had a clutch it was a cheap, easy inspection instead of a crankshaft replacement.
      
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  • Re: Gearbox Clutch

    by » 10 years ago

    Interesting Rob. Curious why Rotax was required to protect the crank with a clutch for certification, while nobody else had that requirement? Does it have something to do with the Rotax press-fit multi-piece crank vs. the competition's one-piece cranks?
      
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