5 ms·

Well, that’s in part a point for the batteries, though. You spend a lot of energy to lift all that fuel that you just blow out with all its potential energy up

by adminu 7y ago

Well, that’s in part a point for the batteries, though. You spend a lot of energy to lift all that fuel that you just blow out with all its potential energy up in the air, whilst the batteries provide you with that very potential energy on the way down as well. Glider planes quiet commonly are filled with water to make them heavier so they can make more use of the potential energy they gain from the externally powered take off and so that they can bridge longer distances without lift generating upwind.

janus 7y ago
Actually, gliders with water ballasts have the same L/D full or empty. The difference is that they can fly faster when the tanks are full, but they don’t travel larger distances
MayeulC 7y ago
Which brings me to the ask the following: Would electric towplanes be doable for passenger aircraft? (Long or short haul, electric or otherwise). If one of the downside of electric planes is the range, while fuel is cheap, making them cheaper to operate, and take-off uses a significant portion of the total energy, I could see very powerful electric towplanes as a way to reduce the amount of fuel needed for takeoff. This would: * Allow to travel longer distances with the same amount of fuel (enabling electric airplanes to fly longer distances). Alternatively, allow planes to fill up with less fuel for the same distance. * Improve fuel efficiency of big airliners, and their carbon footprint if you consider regular ones. One last question: aircraft that fly shorter routes typically embark less fuel, but would that be doable with electric planes?
FabHK 7y ago
That's not a point for batteries. I cannot imagine a circumstance where, during cruise or even descent, you'd wish that you'd be carrying more mass (except possibly to have a higher AoA and thus higher V_a if you want to fly through turbulence faster).

by adminu 7y ago

janus 7y ago

Actually, gliders with water ballasts have the same L/D full or empty. The difference is that they can fly faster when the tanks are full, but they don’t travel larger distances

MayeulC 7y ago

Which brings me to the ask the following: Would electric towplanes be doable for passenger aircraft? (Long or short haul, electric or otherwise). If one of the downside of electric planes is the range, while fuel is cheap, making them cheaper to operate, and take-off uses a significant portion of the total energy, I could see very powerful electric towplanes as a way to reduce the amount of fuel needed for takeoff. This would: * Allow to travel longer distances with the same amount of fuel (enabling electric airplanes to fly longer distances). Alternatively, allow planes to fill up with less fuel for the same distance. * Improve fuel efficiency of big airliners, and their carbon footprint if you consider regular ones. One last question: aircraft that fly shorter routes typically embark less fuel, but would that be doable with electric planes?

FabHK 7y ago

That's not a point for batteries. I cannot imagine a circumstance where, during cruise or even descent, you'd wish that you'd be carrying more mass (except possibly to have a higher AoA and thus higher V_a if you want to fly through turbulence faster).