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Thread: JetEZE crash, Pilot lost

  1. #21

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    Oct 2014
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    Quote Originally Posted by CharlieN View Post
    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.
    I'm not going to speculate on the crash cause, but I want to correct an inaccuracy (and I'm pretty sure we've had this discussion before). Long-EZ's (and all Rutan derivative canards - Variezes, Long-EZs, COZYs, Berkuts E-Racers, etc.) have 100% or more mass balanced elevators and ailerons. If the one in your yard isn't balanced correctly, well, that's not a fault of the design. The only surface that isn't balanced is the rudder, and that's because it only moves outboard and has a hard-stop for inboard movement.

    Correctly built EZ's have been flown and tested to 240 KIAS - possibly higher - without issue. But as has been pointed out, this was NOT a plans built EZ of any type - it merely resembled one.

  2. #22

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    Jul 2018
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    Stupid question, what material is the wing made from? How about the spar and inner structure? What area failed?

  3. #23

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    Quote Originally Posted by enginesrus View Post
    Stupid question, what material is the wing made from? How about the spar and inner structure? What area failed?
    A LongEz from which the plane was derived is made from styrofoam, fiberglass cloth and epoxy resin. This plane was beefed up to be "stiffer" which suggest maybe some carbon fiber cloth was added. The spar web and spar caps are the same materials. Not clear yet where the failure originated.

  4. #24

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    Jul 2018
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    All materials I would not care to trust keeping me so high off the ground. Its bad enough thinking about some small bolts taking some huge stresses, I'm just not a composite fan, and for real Styrofoam? Maybe good material for cushioning items in a box for shipping, but there is no tensile or bending nor shear stress capabilities with that material that I know of. And fiberglass? I've seen way to many kenworth size truck hood fender combo's with major cracking in very low stress area's.
    Wing separation is a no brainer on that one.

  5. #25

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    Quote Originally Posted by enginesrus View Post
    All materials I would not care to trust keeping me so high off the ground. Its bad enough thinking about some small bolts taking some huge stresses, I'm just not a composite fan, and for real Styrofoam? Maybe good material for cushioning items in a box for shipping, but there is no tensile or bending nor shear stress capabilities with that material that I know of. And fiberglass? I've seen way to many kenworth size truck hood fender combo's with major cracking in very low stress area's.
    Wing separation is a no brainer on that one.
    You realise... Nevermind.

  6. #26

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    Quote Originally Posted by enginesrus View Post
    All materials I would not care to trust keeping me so high off the ground...
    If you don't know what you're talking about, it's better not to say anything.

  7. #27
    The foam is just to help mold the skin to the right shape. It does not carry any structural load except to resist oil canning and local buckling, which are all small forces.

  8. #28

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    Jul 2017
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    Quote Originally Posted by David Lewis View Post
    The foam is just to help mold the skin to the right shape. It does not carry any structural load except to resist oil canning and local buckling, which are all small forces.
    I don't think that's exactly true. I'm not an engineer, but I'm pretty sure that the foam is indeed loaded in shear as it reacts lift loads out of the skin and into the spar. An engineer like Marc Z. could tell us for sure, and probably exactly how much.

    --Bob K.
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  9. #29

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    Quote Originally Posted by enginesrus View Post
    All materials I would not care to trust keeping me so high off the ground. Its bad enough thinking about some small bolts taking some huge stresses, I'm just not a composite fan, and for real Styrofoam? Maybe good material for cushioning items in a box for shipping, but there is no tensile or bending nor shear stress capabilities with that material that I know of. And fiberglass? I've seen way to many kenworth size truck hood fender combo's with major cracking in very low stress area's.
    Wing separation is a no brainer on that one.
    You have heard of SpaceShipOne?

  10. #30

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    Jul 2011
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    Many small boats ,from sailboat to powerboats to kayaks etc are made of fiberglass and they work well, I think they might be a little heavy in thick sizes for airplanes. As for strength, think of the pounding a ski boat takes in normal day of hitting waves and wakes and they dont redily crack. Think of the pounding a surfboard takes and it is often a foam core for shape with glass wraps around it for strength.

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