For those wondering about the lack of visible progress in recent months, here’s the explanation:
No aircraft construction project goes without setbacks, especially one where many details have to be developed before they can even be built. One such detail is currently taking up a lot of time and effort: due to the modification of the tail section from the original metal structure to a continuous wooden framework, the attachment of the vertical stabilizer needs to be adjusted accordingly.
To begin with, the forces acting on the vertical stabilizer were quantified in a study conducted by Jürg Müller (Aerodynamics at RUAG Aerospace). The results were impressively high, and directing those forces into the fuselage has proven to be a significant challenge.
This adjustment to the fuselage structure has involved a considerable amount of engineering work to ensure that the stabilizer can be securely attached while handling the required stresses.
Under the guidance of Stefan Bräutigam (Structural Engineer), the design was revised to ensure that the strength of the wood would be sufficient to handle the required forces. Calculations alone were not enough; tensile tests were also necessary to verify that the fastening in the wood could withstand the applied loads. To this end, a total of 27 tensile tests were conducted at the Windisch University of Applied Sciences, with each sample being loaded until failure.
These tests provided the necessary data to confirm the structural integrity of the wood, ensuring that the attachment points for the vertical stabilizer could safely bear the forces involved in flight.
With this information, the calculations were then carried out under the strict supervision of Stefan Bräutigam and documented in a 23-page technical statement.