Hi Dale, You didn't miss all of it yet, because it hasn't all been posted so far, but you missed a whole bunch of it. If you don't have better snakes to kill tomorrow, I recommend cruising the archives for the many, varied, and often interminable discussions on crowning, ribs, etc. There's a TON of it in there. I've stuck to Sitka spruce for both panels and ribs, and haven't had any reason to try anything else. I've thoroughly mutated a scaling spreadsheet to use for designing rib scales using the string scale. Using calculated string tensions, bearing loads from specified angles, and assigning ranges of unisons to individual ribs, factoring in panel expansion lift, I pre-compute individual rib dimensions and stiffness I want using deflection and positioning in the scale as guides. I've got it set up so I can change rib positioning in the scale, width, height, and crown radius and immediately see the results on a graph. So far, I've found it extremely useful for the way I do things. I like the strength and stiffness to weight characteristics of Sitka, and have been able to manipulate rib dimensions to go in the direction I want to go without throwing in another variable of different ribbing material. Generally, I try to keep things simple enough that I can handle them. You're right, it is interesting that so many versions of re-invented wheels end up being similar. Too bad more manufacturers aren't doing more re-inventing of their own. It's surprising what can be learned by breaking things and pondering on the pieces. Ron N
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