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Building Tips and technical articles. => Building techniques => Topic started by: James Mills on November 26, 2006, 08:41:48 PM
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I read a post recently where Brett (I think) posted that he felt an airfoiled stab was an advantage. If you choose this route can it be built as a built up/sheeted stab to save weight or is a foam stab a must to keep the airfoil?
Thanks,
James
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I build mostly flat stabs. Usually a fake solid sheet tail for an OTS airplane. I lay down a piece of quarter grain 1/32 and then build up the stab/ elevator outlines and a Warren truss (or what ever I feel like at the time) out of whatever thickness it takes to make the stab as thick as I want. Then glue another sheet of 1/32 on top. Weight it down between two pieces of 1/4 inch plate glass. Cover with silk, silkspan, tissue, as appropriate. Much stiffer than a solid stab of the same dimensions, and lighter (maybe).
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One thing about a flat stab...You can get it in the fuselage at 0 degrees. Flat! Never can be sure with a curved (or angled) surface.
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I also build flat stabs. I learned how to do this from Les McDonald and I think folks like Paul Walker and Windy also build (or have built) stabs this way. If you build it right, it will be very light AND very stiff - one of Brett's major concerns.
I cannot say if there is any difference or advantage to either method. Brett's results speak for themselves, as do Les McDonald's, Paul's, Windy's et al.
I think it's easier to line up a flat stab than an airfoiled unit and think that is just as important as stiffness.
My two centavos. ~>
Ron
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Wow, flat or airfoiled............ hmmm.........
The two best flying planes I have had had one of each! Neither were foam cores, and both were extremely rigid. Of couse one is the USA-1 and it IS airfoiled, but it is built on a core as Ty described, and the center section is flat where it goes on the fuselage. The "solid CF strip" .007 thick can be used in a lot of places to lend rigidity to the structure with minimal weight gain.
Bill <><
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I build mostly airfoiled stabs. Aligning isn't too hard if the cutout in the fuse is straight and you use an incidence meter. I mostly build them because it's easier to make them very, very rigid and straight and because I imagine that the greater lifting surface it provides allows me to carry the CG further back, though I'm probably just imagining it.