Saturday, November 17, 2012

Good weather for a while.

I got the Yak-9 flying pretty good. The aileron as a trim tab did the trick. I outlined both ailerons with 1/16" black trim tape to hide the cuts. The model has a belly scoop like the Mustang and is painted blue to match the rest of the bottom. I've been seeing the scoop and thinking it is the out board wing. That complicated the trimming process a bit. Yesterday I ordered some poly span covering and some propellers for the Strega.
 It took most of the morning to figure out how to install the cowl hold downs. The plans show a strip of ply across the fuse. and one in the cowl with a bolt to hole them in place. The plane is designed for rear exhaust engines and one is shown on the plans. The plans method for holding the cowl on won't work with a rear exhaust engine. I thought about that for several days and finally used three tabs, two at the rear of the cowl and one in front across from the needle valve hole. A lot of cutting and fitting on each tab to get  the right fit. Then to drill the holes so it lined up with the blind nuts on the tabs glued to the fuse. The center wing ribs are 2-7/8" thick at the fuse. the fuse. sides are 3-1/4" wide. That leaves a very weak strips of balsa connecting the front and rear of the fuse. I ended up installing it into the adjusto-jig for the final assembly and for safety.
This morning I fitted the flaps and built the control horn boxes. The horn is connected at the flap root by some cut out pieces of ply. Very weak. I filled the ply up to the flap surface and added 1/32" ply reinforcement pieces over the assembly. The horn is 1/8" wire and doesn't look to be easily tweakable.
 The molded turtle deck came out fine and will be installed after the wing is glued in place. I made some bucks for the top forward sheeting and have to cut the foam and wet down the balsa. I figure to add 1/16" sheeting to the top and bottom for added strength before installing the molded sections. A lot like the Sig Kougar, Kobra and King Kobra fuselages. I'm hoping for a final weight in the 50 ounce range. 59.9 will do. I thing the final result will look more like the P-51 B than the D model it was loosly designed after.

No comments: