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Exhaust Wrap

in 912 / 914 Technical Questions 8 years ago
Is it Ok to wrap the exhausts in the 912?

I was thinking of wrapping the frist half of the exhausts to keep the exhaust heat away from the engine.
I would use fiberglass as used in motorcycles.

Has anyone tried?

  • Re: Exhaust Wrap

    by » 8 years ago

    I've been wrapping the stainless steel exhaust pipes on Rotax 912's for 15 years and never an issue on anyone's plane. I would never wrap a standard steel pipe due to carbonization. Wrapping will cut way down on radiative and convective heat on wires and hoses and help heat reduction under the cowl. How much does it help. Well if you run the engine with bare pipes would you reach down and touch the pipe. Not if you want to keep the skin on that hand, but I can do it with a wrapped pipe.
    The wrap Mfg's claim a 70% reduction in heat and I don't always believe what an MFG says, but even a 50% is great. I use the 2" wide and only over wrap each edge 3/8" because you do not want to retain excessive heat. I wrap from the exhaust pipe at the head down to and including the knuckle at the muffler joint. In case there is any exhaust gas leakage this will contain it. I use hose clamps to secure the wrap at the top and bottom. Do not over wrap the exhaust springs. You can wrap under them. Do not over wrap an EGT probe as it will cause the temps to fluctuate by 125F. I talked to Rotax and the wrap MFG and no one had a good answer other than the cloth interfered with the resistance. You moisten the cloth to apply, don't soak it. Once you run the engine it will cure itself in position. Wrap it tight not loose. Once burnt it it will be fragile so don't pry on it. There is no need to remove it for an normal inspection. If a pipe were to break you typically don't get little holes the pipe tends to snap completely in half so there is no guessing you have an issue.
    You can buy 2" wide wrap at most automotive stores and it comes in 50' rolls for about $50. It usually takes me about 45 minutes to 1 hour to do all four pipes. You will have enough to do more than one plane.

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

    Thank you said by: Guilherme Tomazini, RotaxOwner Admin
      
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  • Re: Exhaust Wrap

    by » 8 years ago

    Thanks a lot for the info.
    One more question: Are all 912 exhausts stainless? Mine has gone dark so I can't tell for sure. It is from 2004, I guess it would have corroded by now if it wasn't...
      
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  • Re: Exhaust Wrap

    by » 8 years ago

    It should be stainless, but I can't speak for everyone. Try a magnet.

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

    Thank you said by: Guilherme Tomazini
      
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  • Re: Exhaust Wrap

    by » 8 years ago

    Stainless Steel for sure.
    Bob
      
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