- You don't have to worry too much about efficiency from the ground, since resources are plentiful unlike the sky where every gram counts. For example it would be completely fine to have a 20% efficiency from the ground to the sky (if we don't take into account the heating of the wire), for example spend 2kw to get 400w in the drone. Not ideal, but acceptable to many.
- Also, the efficiency can be greatly improved by using high voltage AC and a transformer on both ends. Very similar to how the power grid works, you can use thin cables to deliver a lot of power, I would not be surprised if 90% efficiency can be achieved. This field has been well researched, tethered drones can fly for hours, but the ranges that are useful in war (10+ km) are a novelty.
- You don't have to worry too much about efficiency from the ground, since resources are plentiful unlike the sky where every gram counts. For example it would be completely fine to have a 20% efficiency from the ground to the sky (if we don't take into account the heating of the wire), for example spend 2kw to get 400w in the drone. Not ideal, but acceptable to many.
- Also, the efficiency can be greatly improved by using high voltage AC and a transformer on both ends. Very similar to how the power grid works, you can use thin cables to deliver a lot of power, I would not be surprised if 90% efficiency can be achieved. This field has been well researched, tethered drones can fly for hours, but the ranges that are useful in war (10+ km) are a novelty.