Finally! The shell of the center section is joined. It was a long and tedious way, but worth it:
We had to solve many problems to get there! It is astonishing how well it worked out considering that a couple of years ago we had not much more besides an idea.
Joining the shell was more or less straightforward. We mixed an adhesive based on expoy-resin (130 g), cotton flakes (15 g) and thixotropic agent (3 g). The adhesive was spread on the contact surfaces and the shells were pressed against each other with the mold. While the aft joint is wide, and hence, strong enough, the contact surface in the front is small. Notice also, that the aerodynamic pressure is highest here, as the stagnation point moves around this region. A bursting shell would we simply catastophal. Reinforcement was a must. We laminated and vacuum bagged a layer of biaxial non-crimp carbon fabrics (200 g) from the inside and outside. This should be enough to keep it together in all circumstances.
Here’s a video of how we joined the shells:
The next steps? Well, we have enough to do in the center section: reinforcements of the ribs, canopy, fitting of spars, seat, controls, etc. We hope to start soon with the pattern of the cockpit and canopy. If everything works out as expectect, we should have at the end of the year a cockpit and a clear canopy (produced by Plexiweiss GmbH).