It’s true that a helicopter, looking purely at the physics, can be more efficient based on the even lower disk loading. There are very good reasons however that we see multi-copters proliferating in insane numbers on the battlefield and other applications like agriculture, cinematography etc and we aren’t seeing that with helicopter-type drones. The parts for multi-copters are readily available in large numbers, the complexity is dramatically reduced due to the absence of a swash plate assembly, reliability goes up, maintenance goes way down - and last but not least, our multi-copter was probably 1/10th of the cost of the helicopters that did well. Ultimately the team wanted to build a truly practical drone for this competition.