We redesigned the nose to use a stronger, triangle-based beam structure. The past fuselage designs had mostly been explorations of the pros and cons of the Legal Eagle frame and we finally decided to break away and begin designing our own truss frame during our Design Team meeting on March 16th. We realized that the greatest force the nose would experience under normal operating conditions would be the tensile force from the motor mounted at the tip of the nose. Previously, this load was transferred to the frame through several beams which were mounted normal to each other forming some oddly shaped polygons. Not only are polygons a bad idea when it comes to truss design (they are weaker and it’s harder to calculate the resultant forces), but our previous nose design also put several critical beams in shear as opposed to the much stronger tension or compression they are designed for. The new nose design is completely made of triangles and should be much stronger. The motor mount/firewall sheet metal model was also updated to remove the X-shaped mount for the speed controller. Instead, two wood plates were added in as replacements. If the hood area is going to be used to store our avionics and power electronics, it makes more sense to plate it with wood and not conductive aluminum.
In addition to revising the nose, Design Team also added in the upper cabin beams and redesigned the empennage cross web members to all be diagonal. We realized the vertical web members in the empennage weren’t serving any specific purpose with the anticipated loads on the empennage. Since they weren’t angled, the vertical web members weren’t space efficient and needed to be distributed diagonally.
Lastly, the Design Team revised the rear of the empennage to transition directly into the vertical stabilizer for added rigidity and strength.