I recently finished the fantastic book The Wright Brothers by David McCullough and jumped right into Leonardo da Vinci by Walter Isaacson.
Having just now finished the chapter Birds and Flight I was struck by numerous similarities and differences between da Vinci and the Wrights.
Basically da Vinci was process-oriented and the Wrights result-oriented.
Da Vinci was content to observe, record, and dream. He filled notebooks full of unfinished treatises on various topics as well as studies for unfinished works of art.
His observations about birds and flight were unprecedented, and the Wrights had to rediscover on their own much that da Vinci had already taken note of.
But many of da Vinci’s contraptions seem to be theatrical props designed to mimic what the actions of birds’ wings look like rather than serious investigation into flight.
After all, it was obvious to Vinci that the strength-to-weight ratio of humans made bird-style human-powered flight impossible.
The Wright brothers were mechanics, not artists or scientific researchers. For them their detailed study of birds, like the wind tunnel they made, and so many other things, were merely means to an end.
They realised that man didn’t have to fly like a bird, only glide like a bird. Their airplane was a powered glider, in effect.
Another crucial insight was that the skill birds have in making continuous adjustments as they glide (due to the unpredictable nature of wind) was just as important as the apparatus of flight.
Like Leonardo they knew that manpower wouldn’t do. The Wrights found that no available motor would either, so they had to invent their own, using aluminium to achieve the necessary power-to-weight ratio. (They painted their engine black to conceal their secret.)