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Thread: Composite Spec'ing

  1. #11
    steveinindy's Avatar
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    Yeah, maybe Boeing should go back in time to caveman construction and use tube and fabric. I'll point out to them they are really off base with that composite stuff
    I'm not really sold on the degree of composite use in the 787. I guess time will tell if they overstepped the limits of the technology.

    Maybe someone should tell Burt too?
    If you ever get to actually talk to him about it on a technical level, he's very open about it's limitations and drawbacks. He's an engineer and designer, not a zealot.

  2. #12

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    Well Steve, I'm not sure how much credibility you hope to achieve when you think you're a better engineer than several hundred at Boeing, resort to calling people names when they disagree with you and pretend to know Burt and his technical theories on aircraft design then suggest the system he has been using successfully for almost 40 years and continues to do so to this day is bested by tube and fabric. I know I'm not impressed.....
    I fly a Rutan design and have talked to the Rutans, Mike and a couple of their engineers all of which, by the way, fly composite foam core aircraft. So let's stop the insults and move on. Your "opinons" have been noted.

    The industry has spoken and the results are obvious.
    Last edited by flyingriki; 09-12-2011 at 09:02 PM.

  3. #13
    Mike Switzer's Avatar
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    Umm... The Scaled Composites engineer that taught the class I attended flys an RV. We had a detailed conversation about the pros & cons of the different construction methods.

    Unless you have an autoclave in your garage (like Scaled Composites & the other Boeing contractors do) your composite aircraft will probably be heavier than you planned.

    And Boeing's engineers had very little to do with any of the composite design of their newest product, like every other major manufacturer in this country they are "Engineering Managers" and the work is done by outside contractors. I went to school with a few of their project managers, I have a pretty good idea how much engineering vs project management they actually do now.

  4. #14

    Thumbs Down Like wrestling with a pig.....why bother, they enjoy it!

    Quote Originally Posted by Mike Switzer View Post
    Umm... The Scaled Composites engineer that taught the class I attended flys an RV. We had a detailed conversation about the pros & cons of the different construction methods.

    Unless you have an autoclave in your garage (like Scaled Composites & the other Boeing contractors do) your composite aircraft will probably be heavier than you planned.

    And Boeing's engineers had very little to do with any of the composite design of their newest product, like every other major manufacturer in this country they are "Engineering Managers" and the work is done by outside contractors. I went to school with a few of their project managers, I have a pretty good idea how much engineering vs project management they actually do now.
    OK, since you know it all - let's take this one apart:

    1.Scaled guy fly's an RV - how many do vs. composite? 1.....2....? What does Mike fly? What does Dick fly? What did Burt fly for 40 years?

    2. Mine came out just fine on weight. They were never designed to be built with an autoclave and the weights expected are routinely hit without any issues. A Boeing Engineer that built his own Vari came in at around 600 lbs. ....! No autoclave. Point is your knowledge of composite construction is extremely limited and commenting with such authority is foolish and embarrassing, but I'll never convince you of that, nor care to.

    3. So what if some "other" engineers did the design....you still profess to know better than them, which was the point you avoided with that off-topic diversion to avoid the point. Reminds me of the techniques we get from the White House so often these days.........

    I'm done Mike, believe what you want. Tube and rag, give me a break!
    Last edited by flyingriki; 09-13-2011 at 09:31 AM.

  5. #15
    Mike Switzer's Avatar
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    Huh?? I'm not here to argue with you about what you want to build, I simply told Steve what I decided I was going to do.

    And for the record, I have a Mechanical Engineering degree from Rose-Hulman & I am a licensed Professional Engineer, so I think I am qualified to discuss the subject.

    Use whatever method of construction you want, I don't care. For what I want to build I have chosen the most suitable construction method.

    Besides, the smell of fiberglass gives my sinuses fits.

  6. #16

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    With Tube & fabric, I can design all the structural elements, then add all the controls BEFORE I cover it, makes it real easy to work on, plus the guy that taught the composite class told me tube & fabric was the lightest construction method out there.

    And if it ever gets screwed up. get out the carpenter's knife, cut off the fabric, fix it & re-cover it.
    My main concern with this idea is stiffness. Composites are extremely rigid in those frequencies that cause flutter. I don't really know for sure about fabrics, but I don't see many 200 mph ragwings. Your mission might not call for flying fast with your hair on fire, but if you do want to go lickety-split you might want to keep an eye out for things to do with your control surfaces to make them less susceptible to "the demon."
    Richard Johnson, EAA #395588

  7. #17
    Mike Switzer's Avatar
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    Quote Originally Posted by spungey View Post
    you might want to keep an eye out for things to do with your control surfaces to make them less susceptible to "the demon."
    Control surfaces are way down the road in the design process, but they probably wont be fabric covered. Fiberglass may be a good solution there, but all wood (thin plywood covering) would be also, as well as aluminum, they need to fairly rigid.

  8. #18
    Matt Gonitzke's Avatar
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    If I'm not mistaken, the B-29, DC-6, and DC-7 all had at least some fabric-covered control surfaces, and all were 300+mph aircraft.

  9. #19
    Mike Switzer's Avatar
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    Matt, you are correct, a lot of the WWII aircraft had fabric covered control surfaces. I know at least some models of the P40 did also.

  10. #20
    Matt Gonitzke's Avatar
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    Heck, I saw a picture of Strega from Reno today, and it sure looks like it has a fabric-covered rudder (and went a touch over 499mph!)

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