Today I used the spar jacking technique called for in the construction manual to take the sag out of the spars while they are in the assemble fixture. I used some mason's string stretched along the forward spar flange rivet hole line. Image one shows the mason's string just under the anchor nuts on the spar flange. After that I cut from the supplied 10 x 48 inch stock sheet the wing walk doublers, see image 2.
