ajstead Posted May 14, 2004 Share Posted May 14, 2004 I have a friend who owns a large fiberglass manufacturing business. He and his crew are willing to assist me with my MKIV project (off the clock.. on weekends), but we have a question... Does the entire Cozy MKIV HAVE to be built by hand layup, or can some/all of it be made by commercially spraying the fiberglass over the molds. Fogive me if I'm not up to speed on the proper lingo. I'm JUST getting started. Also, if anyone has jigs they're willing to sell/loan, I'd sure like to hear from you! Thanks in advance for your help! Best regards, Adam Montana Quote Link to comment Share on other sites More sharing options...
Rob Wright Posted May 14, 2004 Share Posted May 14, 2004 The cozy construction technieques are integral to the design. Departing from them would dramaticly alter the plane in ways that would be very difficult if not impossible to evaluate. The construction techniques are specifically designed for a person to be able to build in his or her garage. Not being an Aeronautical engineer, or a material scientist I am unwilling to make anything but the most trivial changes to the plane or construction technieques. Check out the plastic peel ply conversations on this site. This is about as close to a mold as I think you want to get. Besides how would you get the molds... I guess you could take them from a flying cozy. Quote Link to comment Share on other sites More sharing options...
Jon Matcho Posted May 14, 2004 Share Posted May 14, 2004 Does the entire Cozy MKIV HAVE to be built by hand layup, or can some/all of it be made by commercially spraying the fiberglass over the molds.You might indeed be able to use this spraying technique for non-structural parts, such as the nose cone and engine cowling. However, your resulting structural parts will be dramatically different in strength and composition than those produced by the Rutan techniques. You could try to prove this wrong (or right) by building a canard (chapter 10), and repeating this test, which measures the point at which your canard fails catastrophically. But don't bother... Before your friend talks you into building a Corvette , you might want to give this book a read to get a good understanding of what's at work with regard to the underlying structure and materials: Understanding Aircraft Composite Construction: Basics of Materials and Techniques for the Non-Engineer by Zeke Smith (ISBN: 096428281X) Quote Jon Matcho Builder & Canard Zone Admin Now: Rebuilding Quickie Tri-Q200 N479E Next: Resume building a Cozy Mark IV Link to comment Share on other sites More sharing options...
Marc Zeitlin Posted May 14, 2004 Share Posted May 14, 2004 Does the entire Cozy MKIV HAVE to be built by hand layup, or can some/all of it be made by commercially spraying the fiberglass over the molds.Sprayed fiberglass is made up of chopped fibers and vinylester resin, while the hand layups are made up of continuous woven cloth and epoxy resin. If you're building a boat (or a corvette, as pointed out) the former is adequate, but the strength and stiffness will be lower, the weight will be much higher, and the vinylester resin's characteristics suck (that's the technical term) in comparison to the epoxy. It's almost impossible to hold thickness when spraying, and there are no molds. Follow the plans :-). Quote Marc J. Zeitlin Burnside Aerospace marc_zeitlin@alum.mit.edu www.cozybuilders.org copyright © 2024 Link to comment Share on other sites More sharing options...
Spodman Posted May 15, 2004 Share Posted May 15, 2004 You may have been mislead by talk of jigs, they're mostly not for laying up but for holding foam in the right shape/position while you layup over The foam! The book by Mr. Rutan is Moldless Composite Construction (or something like that.) Another pertinent question, how much lard could you take off a Corvette if you made it out of foam & BID? Or would it just get expensive? Quote Mark Spedding - SpodmanDarraweit Guim - AustraliaCozy IV #1331 - Chapter 09www.mykitlog.com/Spodmanwww.sites.google.com/site/thespodplane/the-spodplane Link to comment Share on other sites More sharing options...
ajstead Posted May 15, 2004 Author Share Posted May 15, 2004 Thanks for your speedy answers!! I should probably point out the fact that my friends are not trying to talk me into using the spray method. They offered to help because they think this is a really interesting project. We all assumed that we would probably have to use the hand layup method, but figured it never hurts to ask. I'm still pretty nervous about this project as I've never done ANYTHING like this... but I think I can figure it out. Thanks again for your help! Best regards, Adam Quote Link to comment Share on other sites More sharing options...
Jon Matcho Posted May 16, 2004 Share Posted May 16, 2004 ...I think I can figure it out.I am certain you can, and I'm sure your friends' help will come in handy as well (any help for that matter). I'm sure you'll find yourself to become quite knowledgeable with the techniques of "aviation grade" fiberglass techniques, and before long will be aiding others with your experience. ...it never hurts to ask.No it doesn't, unless you take offense to what might appear as know-it-all behavior, but in actuality is just good info. I for one do not know nearly everything , and after time was able to identify at least one thing Marc didn't know either (even though it had nothing to do with airplanes). So "welcome", and please do feel free to join the discussion! Quote Jon Matcho Builder & Canard Zone Admin Now: Rebuilding Quickie Tri-Q200 N479E Next: Resume building a Cozy Mark IV Link to comment Share on other sites More sharing options...
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