My friend just brought this question up, and I really don’t know of a real answer.
Why on wind turbines do they only use 1 prop, instead of using for instance 2 at the top parallel to each other, spaced out like 10m. but creating independent power (2 power lines running up to the top of the turbine.) Or why not put multiple turbines on the 1 shaft. Save space, rotate more? more power?