Today, I decided to install the trailing edge flaps. I thought this could not be done before the riveting of the lower skins, but it is easily done with the wings in the cradle. The operation is a little scary as the hinge does not leave much toom for play and it is better if the flaps are aligned with the ailerons. The method I choose has been well documented by Dan Checkoway on page 8 of this document: Flaps install. It seems a bit complicatd but is quite straightforward. First I riveted 8 small rivets to hold the skin and the flap brace once the clecos are removed. On the picture you can see the shophead of one of the rivets, behind the cleco. On the other side, the hinge will lie flat, as the rivethead is countersunk.



Then the flap is clamped on the wing, alignment and gap with the aileron are checked. I then drilled one hol out of three and installed some clecoes before drilling the other holes.



All is much easier with a helper, so Guillaume came to give a hand for the alignments and he did the drilling.



Once the drilling is finished, the small rivets get drilled out. After that the skins get lightly countersunk (manually with a deburring tool) to allow a small rivet to be inserted the other way round. On the picture, an idea of the end result once everyting gets riveted together.



Today, the work hour count reaches 500 after 11 months of work. I am very statisfied with the pace : empennage 90% complete, wings 85% complete and fuselage begun.