Phil Hill wrote: >...when faced with cutting out an > airfoil profile, like the ones in our KR plans, do you cut outside the > line, inside the line or right down the middle? The line is so thick, > where you cut it, makes a difference.
It won't matter if the size is a little large or small, or even if you gradually deviate even .100", but as Larry said, be consistent. I modeled and made the "new airfoil" drawings at http://www.krnet.org/as504x/templates.html, and I drew them up with a .030" gap between two sets of lines. My logic for that was to use the outer line to try to cut the airfoil out, but invariably you'll cut off some of the line with the jigsaw, so the second line is there for you to use a sanding block to get really close to the second line. With some care, you could get an almost perfect outside shape. Of course, once you start sanding the foam wings to shape using the airfoil templates as guides, you'll alter the shape anyway. Bottom line with airfoil shapes is to get it close to the intended shape, and it'll fly just fine. I went way out of my way to build mine perfectly to the templates, and the wings to have perfect dihedral and washout, and on my first flight I realized I was going to have to put an aluminum trim tab on one of my ailerons, as well as my elevator. It still flew fine though... Mark Langford ML at N56ML.com website at http://www.N56ML.com --------------------------------------------------------
