eli5: Why is it not possible to build bird-like attachable wings that account for body proportions to allow humans to fly or glide around?

Question

eli5: Why is it not possible to build bird-like attachable wings that account for body proportions to allow humans to fly or glide around?

In: 2102

Answer 1

Grab onto something and try to hold your full weight off the ground long enough to fly somewhere. Now imagine you have to do that, plus flap hard enough to lift your whole weight against gravity. Humans are built to do a lot of things but they don’t have the upper body strength to overcome their weight regardless of how fancy the wings are.