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Thread: JetEZE crash, Pilot lost

  1. #11

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    Quote Originally Posted by Mike Switzer View Post
    Hmm.. I would think that would be plenty strong unless there was some sort of defect.
    Strong enough, almost certainly. But from the facts so far available, the issue appears to be more one of stiffness than of strength, in particular torsional stiffness that increases flutter resistance.

    The kinetic energy available to do aeroelastic mischief is proportional to the square of the velocity. Once you get up above about 200 knots, that curve is awful steep, and once flutter starts it can tear things apart astonishingly quickly.
    Bob Kuykendall
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  2. #12

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    [QUOTE=BoKu;72832 and once flutter starts it can tear things apart astonishingly quickly.[/QUOTE]

    Bingo!

  3. #13

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    That "wave like movement" or flutter the witness reported might be bending. Happens more in long flexible glider wings, I think.
    Last edited by Bill Berson; 09-12-2018 at 07:05 PM.

  4. #14

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    Quote Originally Posted by Mike Switzer View Post
    Hmm.. I would think that would be plenty strong unless there was some sort of defect.
    I agree, I would suspect a defect that led to failure.

  5. #15
    Mike Switzer's Avatar
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    Quote Originally Posted by martymayes View Post
    I agree, I would suspect a defect that led to failure.
    Yea, my thinking is that some of the ERacers with hopped up engines go way faster than he was at the time of failure.

  6. #16

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    If I remember correctly this aircraft had an incident a while back where a downwind landing was necessary. The brakes caught on fire, licking the under-slung tanks and wings. No significant damage was observed at the time. I wonder if the heat caused unseen delamination in the wing skin allowing it to flex.

  7. #17

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    This is so sad. I thought this aircraft was so cool this summer at Oshkosh. I hope they figure out exactly what went wrong. I didn’t know the pilot but his creativity, ingenuity and outright skill were on full display at Oshkosh flying this amazing aircraft. My thought and prayers go out to him and his family.

  8. #18
    Mike Switzer's Avatar
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    I would really like to see if they can find a definite cause of the failure, unfortunately due to the post crash fire & the construction methods used, that may not be possible.

  9. #19

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    Quote Originally Posted by Mike Switzer View Post
    Yea, my thinking is that some of the ERacers with hopped up engines go way faster than he was at the time of failure.
    I think it would be hard to say how fast he was going on that last pass. So far as I know, no video has yet surfaced, and it is way too early for the NTSB data recovery team to have gotten anything out of the avionics.

    --Bob K.
    Bob Kuykendall
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  10. #20
    CharlieN's Avatar
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    My gut feeling is this pass was considerably faster than what was claimed. I can not see how this plane would only be flown at speeds a near stock piston powered version can make a pass at.
    NTSB has the outer wing fragments to look at. Being the failure happened there they can learn allot how delaminations and control surfaces failed. They might not be able to analyze the flutter characteristics or the bending loads induced to the wing from the winglets at this point but can look at how flutter or other loads tore the structure apart.
    Myself, I do not like the four pods under the wing, the airflow between them at speed could well create problems. But it was not the inner wing section where the failure started so I do not expect the pods were a cause.
    FWIW I have a Long EZ here in my yard. The airfoils selected and the lack of balancing of control surfaces may be fine when flown at 200 but I personally would not fly this at 300+ without allot of design changes.
    Regards,
    CharlieN
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