Don, I am not sure that specific gravity or weight of a given piece of timber can lead to conclusions about the shear or tensile strength so easily. I do agree that laminated pieces are superior in stength. I also believe that fir will serve as well as spruce. Indeed I have made many tests comparing sitca spruce to fir, redwood and mahogany and feel that...safety wise a KR could be built with any of the above. Indeed, I have just finished building an Horizon 2 for a non woodworking friend. The kit was all pine. Yes pine. 3/4 square stock for the fuselage with 3/32 plywood covering on the sides and fabric top and bottom. It is amazing what you can get away with. One must just be imaginative, and bold and willing to do a few simple testing. ----- Original Message ----- From: "Don Chisholm" <chizmsupholst...@rogers.com> To: <kr...@mylist.net> Sent: Monday, February 07, 2005 4:14 PM Subject: KR> doug fir
> spar quality sitka spruce is 28 lbs. > per cu. ft > doug fir is 31 lbs. per cu. ft. and is > resultantly that much stronger > if weight reduction is your consideration > reduce the dimensions by 28 over 31 > without sacrificing any structural integrity > by laminating pieces together you can make > it hell bent for strong without adding any weight > Don Chisholm. > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html
