When someone earlier mentioned weight, as opposed to load, it threw me off since weight is strictly a downward (toward gravity) force.
If lift is always perpendicular to thrust and thrust is always in the direction of travel, with load and drag, respectively, being opposite those forces, I...
Got it. I think that set me on the right course, so to speak. :)
I was getting messed up with Bernoulli and flight but thinking about it in light of HallsofIvy's hint Bernoulli's principle seems more like buoyancy, or at least very similar.
So if the airplane rises it must expend at least the same amount of energy from the engine (assuming no losses) as the change in gravitational potential (plus whatever is needed to overcome drag/friction)?
Consider a simple prop plane like a Cessna. I'm a little confused about the origin of the energy for lift. We know the engine accounts for all the thrust and the wings have drag that varies by angle of attack, which also changes lift. But does the engine account for all the energy in lift? If...