RE: Building the Yak 54 - 79"
Nope, doesn't matter whether you build the wing rightside up or upside down, the ribs will always tilt toward the tip a very slight amount. This is because the wings are "quad tapered" meaning not only the le and te edges are tapered relative to the fuselage but also the top AND bottom surface of the wing taper down and upward respectively toward the tip. Look at the picture below which depicts a typical front view of a symetrical wing which is equally tapered on the top and bottom surfaces. If you imagine the root rib vertical and flush against the fuselage, you will notice the bottom and top surface taper equally toward the tip. Now picture this wing panel laying flat on your table and you can see how all the ribs will tilt toward the tip. Doesn't matter if the wing is rightside up or upside down. If it's laying flat along the main spar on your building board, the ribs will tilt toward the tip. I believe the computed angle for my Yak 54 is around 89 degrees. Obviously that's much off of 90 degrees but it's important if you want the wing panel to fit flush against the fuselage.