The physics of how gentoo penguins can swim speedily underwater

A variable called the "angle of thrust" explains why finned wings generate so much thrust.

https://arstechnica.com/science/2023/07/the-physics-of-how-gentoo-penguins-can-swim-speedily-underwater/?utm_brand=arstechnica&utm_social-type=owned&utm_source=mastodon&utm_medium=social