When I laminated my spar caps I used wood a little oversize so I could plane it to the exact dimensions when they were done. Being someone who learned to measure in a machine shop and make parts to tollerances of a few ten thousandths of an inch, I was measuring everything with a set of dial calipers. While double and triple checking everything I realized that there is something weird in the dimensions in the plans.
The 2S plans call for the center section front spars to be 2 5/32" wide which is about 2.1563". The outboard spars are supposed to be 1 15/16" at the root which is 2.9375". They each get skinned on both sides with 3/32" plywood. That makes the center spar about 2.344" which is also the distance betwen the faces of the attach fittings. The attach fittings on the outer spars go inside the inner fittings so we add the two 1/8" fittings to the inner spar to give us 2.375" which is about 30 thousandths wider than the space they go into. Obviously, the fittings will flex a little and you can make them fit, but why in the world would they not just make the center section spars 1/32" wider so the fittings will slide right in? Brian Kraut Engineering Alternatives, Inc. www.engalt.com
