I now have finished all the ribs and the trailing edge of the rudder on both sides. I only have to add the balsa block behind the leading edge / main spar:

I slightly altered the construction proposed by the plans. The balsa doubler of the main spar is designed to be of the same size as the main spar itself, but it already felt quite stiff without the doubler, so I decided this was a bit too much. The doubler now goes from 3 to 6 mm instead of all the way up to 1/2″, so it still has a slope to it and adds a lot of strength, but you will not see it anymore once the covering is on:

I will apply the same concept to the balsa block on the lower half of the rudder.

It’s hard to get a good picture of it, but here you can see it is now symmetrical, being finished on both sides. The trailing edge still has to be sanded to a round shape to mimic the original tube frame:

I think I started thinking about the control horns a little late in the process, as I’ve found a few small glitches. Following the plans the control horn should go like this:

… and that’s also how the ply core is cut, but that’s not correct. The control horn should be placed behind the leading edge or main spar, and not through it:

To fix this I will have to cut through the leading edge. Also, I cut a small noth in the control horn so I can slide it over the ply core:

I could also make the notch in the ply core bigger… but still, this wouldn’t allow me to slide in the control horn from the side, so this solution seemed to be the better one of the two. By the way, the control horn exists of two parts and still has to be laminated (using epoxy).