--- Rick Van Clief <[EMAIL PROTECTED]> wrote: > Shouldn't the thicker carbon go on top? Carbon being poorer in > compression > than in tension and all.
Yes. Carbon uni has compression strength of, say, 100k psi but strength in tension is double that or more. Typical carbon spar arrangement for a 3M ship has .060 * 1/2 on top and .030 * 1/2 on bottom with end-grain balsa core (see http://www.mvsaclub.com/articles/dark_star2.htm for an example). The carbon is so much stronger than the spruce that the spruce serves no purpose once the carbon is on, so you can shave the supplied spruce down to make the laminated spar fit into the rib slot. Also, the typical kit's box-spar arrangement with the shear webs on the sides of the spar caps is less effective than a solid end-grain web between top and bottom spars. __________________________________________________ Do You Yahoo!? Send your FREE holiday greetings online! http://greetings.yahoo.com RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
