I've seen or read several people in various articles saying that hovering in place uses more power than actually flying around. This doesn't make sense to me. To me, the only way that would be possible is if the body were generating some amount of lift by moving through the air. Surely that's not happening is it? In fact, given the way the drone tilts down when flying, I would think it would take more power to overcome the force of the apparent wind hitting that angled surface and pushing the drone down as opposed to just sitting still in the air. Do I have this wrong or do "they"? Thanks.
I had to look this up too and I found a good explanation here. Sorry if this part is too elementary but airfoils (blades, propellers, wings, etc) work with airflow over them. The more "relative wind" coming at them, the more available to generate lift. While hovering, all of that relative wind is being generated by the movement of the propeller (and the work of the motor). When moving forward, a lot of that relative wind is also coming through the movement of the propeller through the air, or so their explanation goes and it makes some sense. Just like any time you're generating lift, there's a curve. Go too fast and now you're working to overcome the drag of the aircraft (and other induced drag) and so require more energy. I was surprised to see that the authors think it's all that much more efficient. I would have thought a bit more efficient but not hugely so. Hope this helps.
I wonder if it might be related to heat. Perhaps forward motion provides better airflow through vents/heatsinks and cools the circuits and improves efficiency.
Some of it may be heat but some may be the inherent efficiency of moving through the air on "wings". I think properly designed planes are also more efficient when moving faster (to a certain point). In the case of a quad or a heli instead of constantly beating on the air and fighting gravity you are partially gliding. That's my guess.
Well if you look at a typical eCalc estimate they seem to say that hovering gives the longest flight time. About 22% more than mixed flight, in this example at least.
