Pietenpol-List: Article on Brodhead in current Atlantic Flyer

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Pietenpol-List: Article on Brodhead in current Atlantic Flyer

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Original Posted By: woodflier(at)aol.com
Here's some considerations around spar construction that don't seem to have beenaddressed very much. First, wt savings 1" routed vs 3/4" solid. Calculating it out, going to be abouta toss up. I suspect the 1" routed (I beam) is stronger than a 3/4" solid...by enough to be worthwhile.. no clue. Given how many champ wings are out therewith 3/4 solid, I'd say probably not enough to matter.Here's some lesser known issues around wood purchasing. Frequently there is apremium on buying wood that isn't a "standard" size. What that means is that4/4 (one inch thick before surfacing) is the most common thickness available.You should be able to yield a 3/4" solid spar out of that stock if you're buyingrough (as in from McCormicks or somewhere). That's probably going to be themost economical all around and for not super well equipped wood shops. Many places sell 1/2" at the same price or MORE than 3/4, as they simply plane4/4 stock down to half of what it was. Takes longer, more passes through theplaner, so it cost more. If you can find some 5/4 (1 1/4" before surfacing), you can plane to 1" finishedand rout, or more economical yet, resaw to 5/8 then plane to 1/2" (if you'recareful and good at resawing). >From somewhere like aircraft spruce, 5/4 is probably prohibitive. From a lumbersupplier, probably very little if any premium for 5/4 over 4/4, you'll justhave less to select from and it'll be about 25 percent more expensive, becauseyou're getting 25 percent more lumber. The price per board foot, is usuallythe same. A board foot is 144 cubic inches, 12x12x1. Mike's built up spars will definitely make the most out of the lumber you have,but you'll need a good cabinet shop full of tools to get the most out of it.If you have that, great! If not, factor in shop services. Quick question for Mike, what are you doing to build up the sections where fittingshook up? Using plywood, or spruce? The bottom line is that you're paying for spruce (or nice doug fir) by the cubicinch. The less of them you turn into sawdust, router or planer shavings, thecheaper. As we know from the weight savings posts (about a very consistent12 lbs per spar set), you're turning about 25 percent of your spruce into dust.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Article on Brodhead in current Atlantic Flyer
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