Working on the left flap this week.
There are lots of dire warnings (even more than there were for the ailerons) regarding building these dudes dead flat. As big as they are spanwise, a bit of washout could make for some interesting handling.
The plans call for making a dead flat table about 8 feet long (already had that from the empennage). The difference here is that you need to make a flat top that can be drilled to allow clecoes to poke through. I got a sheet of 3/4" MDF, ripped it down the middle, and raised it with some dead straight 2x4's so there was enough clearance in the middle.
You lay the flap down, match drill every other skin hole to the table, then take it off and drill the holes out to 5/8".
Here's what it looks like when the holes are mostly drilled:
Once we get that done, we match add the ribs, match drill to spar and bottom skins, cleco, then stick the assembly onto the table. The clecoes on the underside of the skin fit into the previously drilled holes so it lays dead flat.
