While there were several novel designs in the DARPA lift challenge, in the end the winners by a large margin were helicopter and a quadcoptor designs which reached close to 1:4 payload ratio. Both electric or gas engine designs did equally well.

The most interesting part was watching the failure modes: main helicoptor rotors snapping under payload weight, wind gusts sending quadcoptor controls into an uncontrollable regime. Batteries and electric motors heating up under load stress.