Well after a long break its time to start the airplane factory again. I've set a goal for the next year to repeat the build hours of 722 that I put in the first year of construction. I was planning to start on the starting anniversary of Aug 19th but I figured I'd cheat and get a head start today. I've spent the last couple weeks getting organized again and cleaning the shop. Now I'm ready to go!
There has been some discussion on the news group lately regarding multi layers (like around the fuel tank bay) and when to dimple and when to machine counter sink. I have been wondering the same thing for some time but the discussion never really lead to any clear conclusion that I could see. So I figure I'd do some experimenting.
I tried 3 different techniques 1) dimple all three layers 2) counter sink the 2 bottom layers and dimple the top (like the fuel tank cover) 3) counter sink the bottom layer (like the .032 spar) and dimple the other two layers. They actually all 3 worked fine. I measured the thickness of each method and they were all the same indicating a tight fit with all 3 methods. I noticed Eric Newton used the counter sink method around his fuel tank bay and dimpled only the cover: http://mybearhawkpatrol.com/wings/tankcvr1.html The advantage of that is the nut plate can be of the flat variety. Since I have the K1100-6 nut plates which accept a dimple that's not really a factor.
I decided that I'm going to machine counter sink the bottom layer if it's .032 (like the spar) and dimple the rest. In the case of the main tank fuel bay the bottom layer is .032 all the way around and with the aux tank bay just the spar points.
I started deburring the ribs and spars on the right wing frame. I got most of the top side done.
