Bernoulli (1794)


Eddie sez:

You can learn the theory behind airfoils and lift at lift. It really isn't that hard. I took my first aeronautical engineering class in 1975 and I still know the formula for lift.

I can't blame you if you want to pass on this story. Some of these are here because they amuse me.

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The man who invented lift.


Daniel Bernoulli, (Public domain)

We should never forget Daniel Bernoulli, an eighteenth-century Swiss scientist, who invented lift. That he discovered the principle of the inverse relationship between a fluid’s velocity and its pressure is common knowledge, how he did this is less well known.

Intuitively, he knew the equation for lift. He just couldn’t explain it. He traveled to the world’s centers of great thought in search for his answer. He ended up in Venice, where once again his quest remained unsatisfied. In a fit of depression, he went to a bar and decided to drink his problems away. He had an entire liter of beer, which was a lot for him, being a pointy-headed academician. He got up to leave but staggered a few steps and realized he shouldn’t wander the streets of Venice on an empty stomach, so he ordered a pizza. After finishing half the pizza, he left the bar.


Photo: Rialto Bridge, (Eddie photo)

Now for those of you who haven’t been to Venice, the important point here is that the city’s major arteries are canals, which run throughout the city and are bridged here and there with walkways. These canals are pretty much equal in width throughout their lengths except where crossed by a bridge, where they narrow to allow for a shorter bridge, thusly...


(Notice how one-half of the picture looks a lot like half of an airplane’s wing.)

Our hero was walking along one of these canals when he felt his beer and pizza fighting in his stomach, so he ran to the railing and tossed his cookies into the water below.


He walked a little further, but then his stomach churned again so he heaved once more.


Feeling better, he walked along and started gazing about. Then he noticed two pools of his vomit flowing downstream in the canal at about the same pace as he walked. It bothered him so he picked up his pace.

As he walked along side a bridge, where the width of the canal narrowed, he was stunned to see the two pools of vomit accelerated past him.


Yet on the other side the two pools decelerated...


He stood there, dumbfounded, trying to discern why the vomit behaved the way it did when it hit him: “Eureka! Lift occurs when you Consume a Liter of beer, one-half a pizza, and vomit twice!”

L = CL ½ ρ V2

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