Even if the efficiency thing was true, which I have doubts about, the birds couldn't evolve a rotor, since a part rotor is completely useless.Śiva wrote:But, related to the wheel, is the rotor which, when combined with blades (or 'wings'), would surely provide a more efficient means of propulsion through the air for the likes of insects and birds which have a 'hovering' flight mode. A hummingbird with a pair of rotating wings would be far more energy efficient in flight than our current model with its extremely complex, and therefore wasteful, rapid 'beating' motion - at best the current mode for the hummingbird is 50% energy efficient as the upstroke of the wing serves no purpose other than resetting the position of the limb in its socket so it may deliver thrust once again.
Primitive wings are great for gliding from tree to tree, which is how birds and bats evolved wings, long before they could achieve powered flight.
Without the gliding stage, there would never have been birds or bats.
I don't know about insects, whether they went straight to flapping flight, but down at that size bracket, it probably started as being blown around in the wind, or maybe dropping out of trees and drifting to another. I think it's more likely that that started as a primitive glide.
But what's the possible use of a primitive rotor?
