From: "Ugolini, Nick J" Subject: RE: COZY: info Date: Thu, 3 Jun 1999 12:59:40 -0400 I have talked with some Berkuk? guys about their carbon canards planes. They may be stronger and a bit lighter, but the ride is MUCH harsher (less spring), more difficult to work with (antennas, finishing), and of course more expensive. The latest and greatest technology is not always the best for the application. Nick U -----Original Message----- From: Hunter Welch [mailto:nogofsu@sprintmail.com] Sent: Thursday, June 03, 1999 3:15 PM To: German Ferrer; cozy_builders@canard.com Subject: Re: COZY: info Check out the archives and FAQ's for about any topic you can think of. Get one of the books out there for comparison of different fiber glass and remember that a Cozy isn't a Cozy if you deviate from plans Bill W -----Original Message----- From: German Ferrer < german98@cantv.net > To: cozy_builders@canard.com < cozy_builders@canard.com > Date: Wednesday, June 02, 1999 8:47 PM Subject: COZY: info Hi friends, I am very interested in building a Cozy III, and at the moment I am gathering information about the material type for the construction of the airplane, already all we know that the recommended material is the fiber glass but exist in the market fibers more resistant and light like carbon fiber there would be some inconvenience in using this material type in the construction of the Cozy? Regards. Date: Thu, 3 Jun 1999 14:59:52 -0500 (CDT) From: Steven Eberhart Subject: Re: COZY: info On Thu, 3 Jun 1999, Hunter Welch wrote: > Hi friends, > > I am very interested in building a Cozy III, and at the moment I am gathering > information about the material type for the construction of the airplane, > already all we know that the recommended material is the fiber glass but > exist in the market fibers more resistant and light like carbon fiber > there would be some inconvenience in using this material type in the > construction of the Cozy? > > Regards. I love working with carbon fiber but you can't just replace glass with carbon. Carbon is stiffer and stronger than the equivalent weight glass. You can easily create situations where making one part stronger, i.e. a wing, will place greater stress farther down the line, i.e. wing fuselage joint. You can actually end up reducing the point where the complete assembly will fail by strengthining one part. When making structural changes you become the structural engineer and it is your responsibility to do the failure analysis. If this isn't one of your strengths then it is best left to those that are. Even after all of the calculations are done Boeing still breaks a wing to verify that the calculations were correct. Just my .02 worth. Steve Eberhart ------------------------------------- http://www.newtech.com/nlf One test is worth a thousand expert opinions but a thousand opinions are easier to get. --plagiarized from an unknown author All information, in any of my aircraft related correspondence, is strictly food for thought and is in no way intended to imply that it is anything more than ideas requiring additional, qualified, engineering analysis. From: cdenk@ix.netcom.com Date: Thu, 3 Jun 1999 16:55:04 -0500 (CDT) Subject: Re: COZY: info Was asked substitute carbon fiber. The entire airframe is a proven system with specific materials REQUIRED. Added strength per square inch is just part of the story! When disimilar materials are adjacent to each other they are subject to the same movement, one may reach its breaking point before the other. Try a cottom thread and a rubber band stretched the same amount. One will break much quicker than the other. This is one of numerous items to be considered. I am a structural engineer, and didn't substitute on the airframe. But my cowling and wheel pants are carbon fiber, patterned after numerous previous successful similar parts. Date: Fri, 4 Jun 1999 18:51:06 -0600 From: James Russell Subject: COZY: Re: COZY w/ carbon... >Was said >1: The ethical thing would then be to purchase the rights to the details >used from all aircraft kits and plans used. >2: The aircraft could not be called a COZY or a B... >3: What would the weight savings be? and extra cost at $28.75/yd vs. $4.80 >per yard. Hi: Plus, add the enigineering costs...you might as well go to prepreg since you're paying for restressing it ( 35% resin vs. 50% wet-layup )...add freezer, oven, tooling, etc. I think 3 parts is the minimum ( break-even ) to tool up for... We are building one-offs of a proven design...Now you would have a brand new design w/ all the debugging that implies... Regards, James From: cdenk@ix.netcom.com Date: Fri, 4 Jun 1999 17:21:50 -0500 (CDT) Subject: Re: COZY: info Was said 1: The ethical thing would then be to purchase the rights to the details used from all aircraft kits and plans used. 2: The aircraft could not be called a COZY or a B... 3: What would the weight savings be? and extra cost at $28.75/yd vs. $4.80 per yard.