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Exhaust for ULS

in General Tech Discussion 7 years ago

  • Re: Exhaust for ULS

    by » 6 years ago

    Eugene's exhaust pipes have a history of cracking. If they are covered you can't inspect and in his case if a piece of the exhaust system goes thru the prop it could result in a forced landing or would the wrap hold everything together long enough to find a problem?
    Thank you said by: Wayne Fowler, Eugene Klimenko
      
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  • Re: Exhaust for ULS

    by » 6 years ago

    WE have just had an in flight failure of a Turbo (with the associated loss of power) in a gyrocopter where the wrapped exhaust pipes fractured due to heat and vibration. The dislodged part of the pipe then found its way straight into the turbo which only had 40 hours on it.
    The less covering the easier for inspection.

    Regards..........Chook.
    Thank you said by: Eugene Klimenko
      
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  • Re: Exhaust for ULS

    by » 6 years ago

    Vibration, stress and poor welds cause pipe breaks. I have never seen a confirmed case of just the wrap causing a break. If you can show me this where vibration, stress and a poor weld did not cause it please do. There are thousands of Rotax wrapped pipes with no issues and some are well over 1000-2000 hours. The stainless steel with its chrome and nickel content is not like regular steel where it has too much carbon. There are 18 types of stainless and ours is designed for high heat. We used a lot of stainless steel when I worked at Arco Chemicals back in the mid 1970's because of its ability to handle heat and cold. Some temps up to 3000F degrees and some as low as -180F.
    There is no inspection issue with wrap.
    As far as an inspection or a pipe break they don't get a tiny hole or a tiny crack. They snap all the way across and you can hear it. It's a split or shear across the pipe. If you have a break it will shred the wrap at that spot and the wrap will help keep that extremely hot exhaust from ruining nearby items with the hot blast. The wrap is very fragile after it has been heated in place. You won't have any doubt because of the noise, offset in the pipe and trashed wrap. The pipe should never come off if it breaks which does happen and far more times than with wrap.A pipe should never be in danger of leaving the plane. It is attached at the cylinder head and secured below by the springs and you should have safety wire applied in the correct manner.

    You can cause an over heat situation by improperly installing the wrap cloth. 2" wrap should only be over wrapped on the edges by 3/8". If you over wrap the cloth by 1/2 the width (1") then you are the one responsible for causing an over heat issue.

    Here are a couple of pictures of two broken pipes and one repaired one plus a couple of wrapped pipes.
    These never had wrap and in my 20 years have never had a pilot come in with a broken pipe that had wrap although I'm sure there are some out there.

    Most people cause their own problems because of not reading before doing maint. or researching before hand.
    Exhaustpipebreak.jpg (You do not have access to download this file.)
    Exhaustpipebreak1.jpg (You do not have access to download this file.)
    Exhaustpiperepair.jpg (You do not have access to download this file.)
    header_wrap_508_2018-12-29.jpg (You do not have access to download this file.)
    header_wrap_2_119_2018-12-29.jpg (You do not have access to download this file.)

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

    Thank you said by: Eugene Klimenko
      
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  • Re: Exhaust for ULS

    by » 6 years ago

    Thank you!

    So, I should get 2" tape from Aircraft Spruce? Is one brand better than another?
      
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  • Re: Exhaust for ULS

    by » 6 years ago

    No need for Spruce. Your local automotive shop. It comes in 50' rolls. You'll use about 58" per pipe unless you have longer than standard pipes like you see in the picture. Then you might need 62". Use 2". Only over wrap by 3/8" on the edges. It is usually marked on the cloth with a colored thread. You can do something like this in the picture if you happen to have any blow by at the knuckle or want to help keep heat off the springs. Dampen the cloth, do not soak it. Wrap it snugly as you go. You only need to over wrap the first start at the top by 1.5 wraps just to secure the clamp. Same at the bottom. When you start the engine when done it will smell like something is burning. That's just the cloth and will go away in a few minutes. Takes me about 45 min. to 1 hour to do a set of 4. You'll need a pair of scissors, needle nose pliers if you do decide to go under the springs because your fingers will be too big. Then a screwdriver for the clamps. Once on you should never have to mess with it again.
    header_wrap_1_175_2018-12-29.jpg (You do not have access to download this file.)

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

    Thank you said by: Eugene Klimenko
      
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