There is only one Airworthiness Directive on the WACO NINE. It was the result of wing spars on the upper wings twisting and cracking at the root ends. At the time the belief was that it was the result of poor quality spruce used in the spars, but no one knew for sure. I have the factory drawings for the parts and how they were to be installed. The installation drawing gave the idea of how to do the installation but no actual dimensions for where to locate bolt holes.
I spent a few hours bringing up the old drawings in TurboCAD, scaling them to actual size and the redrawing the parts to work out what they planned for hole locations
With these dimensions I've located the holes on the first 2 spars. I've drawn the parts on the spars to help make installation more obvious later. The upper and lower straps go on both face of the spars with 1/4" bolts.
There are also clamping plates on the top and bottom of the spars . I'm not sure this makes a big difference but we will comply.
The fittings for the wing struts and brace cable are also drawn on the struts to help make it obvious later.
This last bit is the taper down to the wing tip bow on the last 12 inches of the spars.
I'm going to lay out the areas to be routed as well, and I have the other 2 upper spars to finish marking up.
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