Date: Wed, 27 Aug 1997 06:06:11 +0200 From: Jean-Jacques CLAUS Subject: COZY: Carbon Canard Spar Cap ? Fellow builders, Has anyone layup the canard spar cap with carbon fibers ? Which carbon fibers can i use for this ? Where can i buy it ? much thanks for your replies JEAN-JACQUES CLAUS Aix-en-Provence - FRANCE COZY CLASSIC #CC1056 Second wing finished - starting canard fpjjc@hol.fr Date: Wed, 27 Aug 97 08:22:20 EST From: "KEN SARGENT" Subject: Re: COZY: Carbon Canard Spar Cap ? Have been considering packing the spar cap with carbon fiber rods from NEPTCO. But, they sent me a letter saying they are now longer making them. Darn. This would make a very weight efficient, but stiff spar. A general comment on using carbon here is you will have a very stiff wing, and consenquently, stiff flying machine. Flying a lot in south Florida on hot afternoons you want flexy wings. Don't know how smooth the air is in France. You can adjust the laminate schedule to get equivalent stiffness, but you will depend more on the carbon fiber strength do this. Even then, carbon will allow 2% strain. FRP will alow 4% strain. Just happen to be launching the production of carbon fiber ride vehicles and have found 3K carbon is in short supply because of a Boeing project (Osprey?) I even called Aircraft Spruce to buy all the Voyager cloth they had, they could no longer supply large quantities. Ended up having to go straight to Owens Corning, who just bought Hercules that makes the fiber, to secure 2,000 yards. Aircraft Spruce may be able to supply what you need for a canard. 1K carbon is more available but very expensive. You may be inclined to look at 6 and 12K fiber for spars, but the physical properties of your laminate will suffer. 1K, 3K, 6K, and 12K are the size of the fiber tows that form the cloth. Try Aircraft Spruce or brows www.acp-composites.com to see if they will sell you a unidirectional 1K or 3K stitched carbon cloth. Expect to pay 30-40 US$ a yard however. You may want to wait until 98 for prices to stabilize. Ken Sargent Cozy #555 ken_sargetn@wda.disney.com Thanks to you guys I'm stuck on the headrest now. ______________________________ Reply Separator _________________________________ Subject: COZY: Carbon Canard Spar Cap ? Author: Jean-Jacques CLAUS at DISNEY-WDW-INTERNET Date: 8/27/97 5:46 AM Fellow builders, Has anyone layup the canard spar cap with carbon fibers ? Which carbon fibers can i use for this ? Where can i buy it ? much thanks for your replies JEAN-JACQUES CLAUS Aix-en-Provence - FRANCE COZY CLASSIC #CC1056 Second wing finished - starting canard fpjjc@hol.fr From: SWrightFLY@aol.com Date: Fri, 29 Aug 1997 09:42:02 -0400 (EDT) Subject: Re: COZY: Carbon Canard Spar Cap ? or any changes from the plans. I think its great that we have the freedom to not build as the plans tell us to build and venture off into the unknown. Minor changes are OK if approved by the designer but for major changes (spar cap modifications) I strongly recommend we have a clearly defined goal that we are trying to achieve by not following the plans. You should also be (or have access to) a competent structures engineer to help verify that the change is OK and will not adversly affect the entire structure. You should also change the name of the project with major changes to, (for example) a Whiz-Bang 2000 or a speed king 100. I had a friend who made his Varieze wings out of carbon to "make them lighter". The stiffer wings (which ended up the same weight as mine) caused the wing attach points to fail during load testing. He gave up trying to "improve" the design and cut up and trashed the project. What engineering talent do we have in this group? Do we have any test pilots in the group? Steve Wright Date: Fri, 29 Aug 1997 08:47:18 -0700 From: Michael Antares Subject: Re: COZY: Carbon Canard Spar Cap ? or any changes from the Also note a recent article in Kitplanes about the issues around combining different materials in an attempt to make something stronger--it has the possibility of actually making it weaker! Michael 6077 Old Redwood Highway Penngrove CA 94951 707.792.7971 Cozy#413 Finished through chap 14 except chap 13. Chaps 16 & 24 mostly finished. Now on chap 20. One wing/winglet finished, working on second.