This is, and was intended to be, a learning exercise.
I don't know if I'm repeating myself, but I started with an old LPP wing, ready for the scrap heap (where it is now). It was covered in a very unskilled manner with Ultrafilm. There was loads of slack on both sides of the dihedral break rib. I read thru the advice, including some that came in offline. First thing I made a soft balsa tweezer about 1/4" wide. Then I ran glue onto both sides of the rib and clamped down with the tweezer along the rib from the top. This drew in 1/16" of film on each side of the rib, which made a big difference in contour but there was still some sag left. In addition, the rib now projected above the top surface of the wing (although the airfoil was correct, only 1/16" south of where it should be). I let that dry, then glued both sides of the rib from the top and came in with the tweezer from the bottom, drew in another 1/16" of film on each side of the rib, and pushed it back up to the top. Now I had eliminated 1/4" of excess film and it almost looked perfessional.
For the new wing, I made a copy of a fixture devised by John Barker (the Atlanta one), deployed the OS film on it, and stuck the bones onto the film. Once dry and cut loose, I added 30º of dihedral and there was no really objectionable sag. However, in the interest of learning how to do it right, where there's only a maximum of 1/16" to be pulled out, and only on one side of the rib, what would you do with it? Glue the top and work the film into the glue with the tweezer from the bottom? Or let it go?
The new wing is really clean looking and has rendered the model 300mg underweight. That's a first for me.
a.
Received on Tue Aug 27 2013 - 21:01:38 CEST
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:48 CET