This vehicle was built and flown in August 2021
This was a really fun project. I only spent a week on it, as it an idea I had while working an internship. The vehicle can yaw incredibly fast compared to conventional designs and has fabulous potential for extremely maneuverable flight. Another clear benefit of this design is that all four motors face the airstream in forward flight, allowing for efficient long-range flight without the weight of an unusable powertrain.
Unfortunately, there was a problem with yaw oscillation. Because the motors were so much more powerful than the servo assembly, without any mechanism to prevent back-driving the motors would torque each beam and throw each beam back and forth as it desperately tried to correct for the huge amount of what amounted to mechanical slack in the tilt mechanisms. Because this was a weekend build, I chose to spend some time tuning the flight controller and eventually dropped the yaw P-term almost altogether. The servo control of the beams was manually mixed into my controls, and eventually, the aircraft was mostly flyable. The first test was a success, even transitioning to and from the forward flight.
The next test was not so successful, as I tried to transition in a small space and the vehicle lost altitude before it landed harder than I intended. This broke more than I realized, and after some small fixes, I tried again, during which a motor came loose and tore the vehicle to pieces as the beams twisted and the entire conglomeration spiraled to the ground.
In revisiting this project I would certainly design a tilt mount that could not be back-driven by the motors, and ensure the wings were sufficiently sized for the vehicle’s weight.
Jordan's Juide 