Originally Posted by seagull10
I think he has pretty good understanding and explanation how fan - flapping ornithopter's wings work and especially to the moment when flapping speed is faster than forward speed. I will just suggest him to replace the term "Partial vacuum" with "Lower pressure area" everything else is OK for me.
I understand that a low-pressure area is a region where the atmospheric pressure is lower than that of surrounding locations and a partial vacuum is anything between zero and 14.7 inHg.
I prefer calling it Partial vacuum on the phenomena that can change place in every wing stroke, (25 times/second on the humming bird flapping).
Some flies beat their wings up to 1000 times per second.
The “Kjell-Effect” is there in every stroke.