After much delay, I am finally getting around to counter sinking all the holes in the wing spar flanges. (BTW - I?m building a ?9) The instructions say to ??mark the orientation of the spar?and study the plans until you understand how the spars are installed. You do NOT want to build a wing upside down!? Well, after studying the plans and staring at the spar for a while, I ?understand? how the spar is installed, but don?t ?understand? how the spar was built!
While ?studying? the spar and plans, I noticed that the upper and lower spar flange bars (the thick stepped bars that run along the top and bottom of the forward side of the wing spars, W-906 B & D) are in the opposite position from what I would expect. The bottom flange bar is shorter and gets thinner sooner than the top flange bar. This is counter intuitive from what I would expect - at least to me! I would think the longer and thicker flange bar would be on the bottom (bottom of the spar loaded in tension) with the shorter and thinner bar (loaded in compression) on the top.
Anyone else noticed this? I?m just a ?dumb? engineer, but what am I missing here?
Scott Harding
RV-9 ? Slowing working on wings
Sugar Land, TX
While ?studying? the spar and plans, I noticed that the upper and lower spar flange bars (the thick stepped bars that run along the top and bottom of the forward side of the wing spars, W-906 B & D) are in the opposite position from what I would expect. The bottom flange bar is shorter and gets thinner sooner than the top flange bar. This is counter intuitive from what I would expect - at least to me! I would think the longer and thicker flange bar would be on the bottom (bottom of the spar loaded in tension) with the shorter and thinner bar (loaded in compression) on the top.
Anyone else noticed this? I?m just a ?dumb? engineer, but what am I missing here?
Scott Harding
RV-9 ? Slowing working on wings
Sugar Land, TX