This reminds me of one of Aesop's fables. The cat and the bell I think, where, briefly a man buys a cat to solve his mouse problem. The poor mice now have problems foraging for food and scouting, so a mouse comes up with an idea, by tying a bell to the Cat. Everyone agreed, but who was going to tie the bell to the cat?

@Jackeea
Must you treat everything like a joke?

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Of course it's possible, just the perpetual part isn't. The engine will also have to be efficient enough to run on a day that's not cloudy, and having to not fly through many clouds to keep going.