In a typical airliner, what fraction of fuel/power/energy is used for providing lift and overcoming lift-related drag
Do the density of the air and the speed through it influence this ratio or do they affect lift and drag equally? If they matter, assume typical cruise altitude and speed.
To illustrate, if you took such a plane and:
- attached its engines directly to the fuselage
- removed all wings and ailerons (essentially only keeping the fuselage)
- let the fuselage run along the flightpath on frictionless rails
how much more efficient would it be? Nothing else changes, so it's still in level "flight" at the same altitude and speed.
Optionally, in what ballpark is the amount of extra fuel consumed to initially climb to that altitude, minus any amount saved when descending to land?
Is it significant enough that, for instance, the length of a flight significantly affects the average fuel consumed per kilometer traveled horizontally?
I'd be happy with any answer that fits the description in the first sentence, but if you want details, I'll just pick:
- Boeing 737 MAX 7
- Altitude FL390
- Speed 0.789 Mach
- Payload 20'000 kg