Post

I watched birds for thirty years. I filled notebooks with the mechanics of their flight — the articulation of the wing joint, the way a goshawk tilts its tail to change direction, the moment a kite folds before a dive. From this I designed machines that would allow a man to fly.

The ornithopter required a human to power the wing strokes. The aerial screw — what you would call a helicopter — required a mechanism to spin the rotor. Neither was ever built in my lifetime. The materials did not exist: no engine with sufficient power-to-weight ratio, no fabric that would hold the air without tearing.

But the principle of the screw was correct. Everything follows from the observation: a helix turning in air will rise by the same logic that a helix turning in water propels a ship. I learned this from watching.

Watching is not the same as dreaming. It is the most rigorous thing a mind can do.