For those curious about the physics of these aircraft, here's an analysis I did of the same concept. The goal is to determine the smallest aircraft configuration that can indefinitely sustain flight: https://github.com/gusgordon/atmospheric_satellite#readme
Is there a reason you optimized the amount of starting energy in the battery? I know basically nothing about how solar power works, but surely you'd just fill the battery up to 100% with an extension cord on the ground before launching it?
Good question. One requirement for the aircraft in this optimization is that they must have more energy in the battery than they did 24 hours prior. If the aircraft started at full energy, they wouldn't ever be able to satisfy this requirement, so that's why it's an independent variable.
For example, an aircraft could "start" at 50% battery state of charge, then charge to 95% over the course of the day, then come back 24 hours later at 51%, and that would be valid. There are other ways around this, but this is what I came up with at the time.
This is similar to why the starting altitude is allowed to float. The gravitational potential energy of the aircraft can be used as another "battery", but the aircraft is only a valid solution if it's not losing altitude over the course of 24 hours.
Maybe it helps surface how much charge is required to climb to altitude vs how much charge is required to sustain it? This may also help surface how much of a buffer you may have in takeoff time in order to survive night. E.g. if you require 100% charge then it's likely you have to take off at a fairly specific time of day.
onychomys|4 years ago
gusgordon|4 years ago
For example, an aircraft could "start" at 50% battery state of charge, then charge to 95% over the course of the day, then come back 24 hours later at 51%, and that would be valid. There are other ways around this, but this is what I came up with at the time.
This is similar to why the starting altitude is allowed to float. The gravitational potential energy of the aircraft can be used as another "battery", but the aircraft is only a valid solution if it's not losing altitude over the course of 24 hours.
jcims|4 years ago
pault|4 years ago
mkr-hn|4 years ago
edit: remember the context. This is about an abstract optimization to find the minimum viable aircraft.
algo_trader|4 years ago
Is it feasible to operate these at lower altitudes?
e.g. can we have solar/air drones posted every 100 miles of interstate highway?!
gusgordon|4 years ago
zucker42|4 years ago
What's the usefulness of this or was it just a random example?