YOU WILL NEVER Understand Lift

Forget it. You haven't got a chance. So I muttered to myself as I closed a fascinating book called, The Enigma of the Aerofoil.

- PETER GARRISON

THE AUTHOR, David Bloor, is an emeritus professor at the University of Edinburgh whose field is the sociology of science: how cultural and personal factors shape the acquisition and use of scientific knowledge.

Bloor’s story, which unfolds like a genial Foyle’s War-style slow-motion whodunit from the BBC, concerns the efforts of scientists and mathematicians in the ivory towers of England and Germany between 1909 and 1930 to understand how wings produce lift.

Their work went on parallel to, and largely insulated from, that of manufacturers and aeronautical engineers, who built tens of thousands of aeroplanes without worrying about why wings worked. They did — that was all that mattered.

The sense in which scientists understand something is not the sense in which you and I do. We know what it feels like to stick a hand out the window of a moving car, to sail a boat or to carry an umbrella on a windy day. These are direct, elemental experiences, familiar since childhood, and we have no difficulty extrapolating them to the wings of airplanes. We understand lift by empathy: We feel it.

But that is not the kind of understanding that exercised the giant brains of Cambridge and Göttingen. They were not Impressionists. To them, understanding wings meant finding the mathematical laws that govern them and that would allow accurate prediction of their behaviour. These laws were elusive. Not that much of the grunt work hadn't already been done: Mathematical descriptions of the behaviour of frictionless “ideal fluids” under highly prescribed conditions had been developed in the 18th century by Leonhard Euler and our old pal Daniel Bernoulli. But real air is not a frictionless fluid; there, so to speak, is the rub.