Cleco the Rear Bottom Skin to the Bottom Skin. Position the Longeron on the side of the Bottom Skins. The Longeron is properly positioned when the skin is against the lip on the Longeron at the start of the radius. Position the Longeron so there is excess on each end of the Skins, they will be trimmed later. Back drill with a #40 drill bit through the holes in the Skins into the Longerons and Cleco. With a #30 drill bit, expand the holes.
