lml@lancaironline.net Mailing List Archive

<<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> In a message dated 2/1/01 1:26:29 AM EST, lancair.list@olsusa.com writes: << One thing that I would not do is force the wing into position and then drill your trailing edge holes for the aft spar bracket. It seems to me that the tension will cause load problems on the spars that shouldn't exist. >> Well, let's think about this. Each wing panel holds up half the weight. Say 800 pounds each. 9 G's is the design ultimate load -- that's where it should break. This corresponds to a vertical upwards load of 7200 pounds on each wing panel. I'd say that if it took a hundred or so pounds to get the wing incidence straight, the wing structure will never know. I'm told (by the factory and builders) that the time to finalize the wing incidence is when bonding the lower panels to the wings (closing them out) rather than when attaching them to the stub wing. I know of one builder that had his airplane upside down and hung weights from the leading edge to induce a twist during closeout in order to remove a twist that was built into the wing as delivered by the factory. I think he used well under 100 pounds for this. He says his airplane stalls without rolling off on one wing. Concerning finishing, I have two things to say: (1) The smoothness of the bottom of the wing and fuselage is not that important. Not aerodynamically and not aesthetically, unless you're trying to build a Grand Champion. (If someone's going to crawl under your airplane and grouse about it, kick them in the shins!) If you're trying for a Champion, more power to you and best of luck, but rest assured that I won't be your competition. I may, however, be flying while you're still building! (2) I stood next to an absolutely gorgeous 360 at Oshkosh last year. After 2-3 days I suddenly realized that there were some ripples in the wing finish. When I looked for them I could see many more. But the thing is, it took me, a fellow builder, almost half a week to notice them! The builder of this airplane also said "you never finish, you just get get sick of it and say it's good enough". His airplane was plenty good enough and it still had ripples. Engineering is the art of the "good enough". - Rob Wolf >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LML website: http://www.olsusa.com/Users/Mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please send your photos and drawings to marvkaye@olsusa.com. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>