Re:How trains could replace planes in Europe
by Dylan16807 on Thursday November 11, 2021 @05:26PM
(#29194062)
You're describing something like the rocket equation, but that's for increasing final speed, not increasing mass.
If you double the weight of "the plane", that includes the batteries and motors.
If you start with doubling just the structure, then you might need to add 50% more batteries, not "twice as much". Then to lift those batteries it takes another 30%. Then you add bigger motors which adds even more weight, etc. etc. By the time you finish, the total weight will be about 2x your initial weight.
There is difficulty in scaling planes, but it's not because more mass requires more fuel. A fixed percentage devoted to fuel works fine, if you're assuming the same route for both planes.
If you double the weight of "the plane", that includes the batteries and motors.
If you start with doubling just the structure, then you might need to add 50% more batteries, not "twice as much". Then to lift those batteries it takes another 30%. Then you add bigger motors which adds even more weight, etc. etc. By the time you finish, the total weight will be about 2x your initial weight.
There is difficulty in scaling planes, but it's not because more mass requires more fuel. A fixed percentage devoted to fuel works fine, if you're assuming the same route for both planes.