Hey, first post! I happened upon this forum and after about ten seconds of perusing topic titles, decided this forum was definately for me! Here is my question. What type of cross section would a beam need to be the most efficient at handling 1) tension and 2) compression. I am working on a science olympiad boomilever, kind of like someone else who made a thread recently. I attached a picture (hopefully correctly) that shows what the boomilever will look like basically. It has to support a 15 kg weight 40 cm from the wall, and be as light at possible, like 10 or 15 grams (!). Heres what I have in mind There will be two 40 cm compression chords, and one 45 cm tension chord. The lever will be mounted by one bolt just above where the tension chord meets the wall. The chords have to be smaller than 1/4" by 1/4", and I will make them by laminating several 1/16" sheets of balsa or bass. I have heard that bass is better for compression and balsa is better for tension, but bass is heavier, and I dont want 2/3 of my lever to be bass, so I think I will try first with all balsa, and switch to bass if the compression chords are too weak. OK so for my second question. Would having only one tension chord be alot weaker? Am I correct in thinking that the tension chord should be rectangular, with the thickest dimension supporting the downward pull? What about the cross section of the compression chords? Terribly sorry if all of this is unclear, be sure to look at the picture and ask if anything needs clarification. Thanks!