On Tue, 16 Nov 1999 05:28:10 -0800 (PST), Edward Nolan <artsfoto@yahoo.com> wrote: >FlyBaby > >Hi, > >Is there a "rule" for grain orientation when the >length of the spruce (say 16' longeron) and the height >and width of the piece are square? As glued to the >fuselge side, should the grain run paralled to the >side of the fuselage or can it be--relatively >speaking-- perpendicular (obviously depending on the >grain's slope)? Is their a strength difference >between orientations? How about for vertical members >that connect bottom and top longerons? The stickler's answer is that the grain should run horizontally in your longerons, but it doesn;t much matter. They are so far apart that you can consider them in simple compression and tension rather than as part of the overall bending load. Don't sweat it for longerons. >Also, if plans call for a 16:1 scarf joint, does that >mean that the scarf should be 16 X the thickness of >the piece of wood? Example: 1/8" ply X 16 =index.html 2", so >the overlap of the two pieces should reach back a full >2" from the edge of each piece? Yes 16 times thickness. >Is there a good resource for general information such >as this? There is an EAA book on Wood airplanes that's pretty good. It's a collection of magazine articles that have been published over the years. Call them up and ask for the wood book, and I think they will know which one. >I know these are very basic questions, but I'm new to >the game. David E. Munday E-mail: munday@engr.uky.edu Dept. of Mechanical Engineering Web: http://www.engr.uky.edu/~munday 521 CRMS Building Voice: (606) 257-3263 University of Kentucky FAX: (606) 257-3304 Lexington, KY 40506-0108 Office: 202 D. V. Terrell Bldg.