Seth Jersild wrote: >>If the cumulative weight of all the materials adds up to just a few ounces >>more with the 5048-45, then I'm sure not going to worry about going with a >>stronger spar. Please forgive my ignorance--in a couple of weeks my >>garage will be full of spruce and I'll start getting a much better sense >>of things.<<
There's never been a spar failure of a KR built per plans, so the spar is plenty strong enough already...unless you count the deliberate failure at the Gathering when we broke one on the ground for kicks, and it was very impressive how far they bent before failure. I'd go the weight-saving way, personally (and that's what I'll do on my next plane). There's a spar analysis spreadsheet at http://www.acrodesigns.com/excel/SparStrength.xls that would allow you to enter the stock spar dimensions of the plans version, extend the center spacing, and then "back into" a spar cap thickness. Of course then you'd have to customize your wing attach fittings for the thinner spar caps, so maybe the extra pound is better after all... Mark Langford ML at N56ML.com website at http://www.N56ML.com --------------------------------------------------------
