From a commenter under the video:
Summarized the measurements, with rough timestamps:
Stock blades (6:43): 1 m/s, 64.3 W,
simple airfoil (7:55): 0.8 m/s, 66 W
modern airfoil (9:12): 1.2 m/s, 64.5 W
stock motor no blades (13:49): 53.8 W
BLDC motor no blades (16:24): 8 W
BLDC stock blades (18:27): 1.8 m/s, 59 W
BLDC stock blades at reduced speed (19:35): 1.0 m/s, 27.3 W
BLDC motors, also called brushless, is the silent geeky revolution that brought us lighter, cheaper and more efficient robotics. It also allowed to make battery-powered electric version of many gardening equipment. More precisely, it is the design of cheap lighter controllers that made all of this possible (a good controller will require a fast-ish microcontroller on board)
Kind of a niche subject but happy to see it here!