Having previously pre-drilled the 3/32 pilot holes in the bottom skin, today it was time to make the final bellcrank cut outs and form the holes for the strut attach strap penetrations.
I double checked the level of the wing and made sure of the correct amount of washout, and then started drilling through the pilot holes, working from the centre area outwards after setting up a hair dryer to blow hot air into the wing to create a small amount of expansion of the skin, thus helping to minimise the 'Oil Canning' of the skin between the ribs & stringers.
Pre drilled skin with the bellcrank cutouts
checking the washout at the wing tip trailing edge.
Started drilling the holes into the ribs & stringers from the centre area outwards.