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Thread: Speaking of roadable aircraft....

  1. #61
    steveinindy's Avatar
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    At just 220 pounds dry, the motorcycle is easily carried in place of passengers.
    220 lbs is pretty light for a motorcycle.

    The tie-down straps and anchors were designed to secure the motorcycle to Part 23 standards, including the 9g forward crash case.
    Just a heads up but you do realize that most/some of the Part 23 standards are pretty low so far as the scale of survivable crashes since it's based in part on some 1940s ideas about the tolerance of the human body to deceleration (like that 18 g was the whole body cutoff for escape from a crash without injury). There's a reason why the seat standards for most aircraft are between 16 and 24 g now. This is kind of my area as I work with crash survivability data for a living so if you need any help with it, feel free to PM me.
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  2. #62

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    We use the engine and frame from a lightweight 225cc Yamaha (238 pounds dry) and do a lot of work to make it even lighter (220 pounds). It's a great fit... light enought to carry in many airplanes... and it still hauls two adults down the highway.

    Thanks for your concerns. We do treat Part 23 as a minimum standard and adopt greater load factors for our structural engineering, even on our non-certified projects. In this particular case, the tie-down system was designed to handle, by itself, conservative crash loads. In addition to this, the welded fixtures were designed to distribute forward crash loads against the wing spar.

  3. #63
    steveinindy's Avatar
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    However, the designers included an enormous 85 gallon tank for those occassional long trips
    ....or to make the crash sites easier to find. There's a reason why they are known as "Ronsons*" in the aviation safety community. You just follow the almost trademarked pall of black smoke. That whole line of aircraft has to be one of the best arguments against the integral fuel tank.


    *-For those of you not old enough to remember, Ronson was a cigarette lighter brand with the slogan "It lights the first time, every time".
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  4. #64
    steveinindy's Avatar
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    In this particular case, the tie-down system was designed to handle, by itself, conservative crash loads.
    The problem is that a "conservative" crash load (according to the FAA) tends to be about half of what a person can survive. There's a reason why a significant number of people tend survive crashes only to perish in the post-crash fire.

    We use the engine and frame from a lightweight 225cc Yamaha (238 pounds dry) and do a lot of work to make it even lighter (220 pounds). It's a great fit... light enought to carry in many airplanes... and it still hauls two adults down the highway.
    That's pretty cool. I guess my definition of weight so far as bikes has been kind of skewed growing up around my uncle and his friends who all ride Harleys. LOL
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  5. #65

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    (tongue in cheek) There isn't a Cessna single in the world that hasn't taken off over gross (and I believe that 10% is legally allowed in Alaska). Fuel is actually a wing stress reliever ... except on landing. None of these airplanes had a published, maximum zero fuel weight (but I believe that it is the same as the aircraft gross weight). Sounds like you're doing it right. Useful load in my P172D was 1,100 lbs.

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