Voting Result: 2.66294861623
Overview for UAXAC
UAXAC ("Eagle" in maya language) is designed to be efficient.
Sergio de la Parra and Oriol Gallemí squeeze their minds to design a vehicle sticking to the requirements and to maximize the lift/drag figure to be capable of efficient sustained flight. Drag is minimized by means of eliminating sharp edges and useless wet/turbulent areas.
By eliminating the huge payload from the Flight Termination Devices, the team started a mass decreasing design spiral, where every design looked differently to better fulfill the new requirements. Removing those 1,2kg decreased the design mass by almost 7 kg, and minimizing the steady-power consumption by 20W (180gr of batteries). At the end, a high capacity cell instead of a high discharge was used to improve by a 2x factor the energy on board without abusing the battery while enhancing battery life. In its turn, that decreased the mass of the motors, the overall mass and changed the wing profile in several iterations.
The final design is a tailsitter, tilting-wing, mainly made out of hollow foam inside of an infused carbon skin body (and wings) with thicker reinforcements to accomodate payload fixing points, motors, actuators and sensors.
The design maintains the direct-drive, fixed pitch propellers approach and avoid electric propeller locking (excess of energy consumption), while alternatives could be envisaged to maximize efficiency in both modes.
The simpler, the better.
Wish you like it as we do !