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

The primary answer is pectoral muscles.

To propel a human-weighted person to flight, you would need immense pecs. Last I heard, you would need something like G sized boobs, except pure muscle, with all the relevant anatomy to match (bones, sinew etc.)