In fluid dynamics you have to smooth whatever you can, whenever you can, as much as you can.
[A. Jameson, 1994]
… if we further assume that the atmosphere has been well mixed by turbulent motion, so that all the molecules have scattered in the course of the last two thousand years, it follows that every time we breath we inhale at least one molecule of breath that Julius Caesar exaled when he was murdered in the Roman Senate house in 44 B.C. …
[PP Wegener, in What Makes Airplanes Fly ? , 1991]
Give me an engine big enough and I’ll give you an ironing board that will fly supersonic.
[Not sure about the originator, certainly and American aircraft designer]
The helicopter appeared so reluctant to fly forward that we even considered turning the pilot’s seat around and letting it fly backward.
[Igor Sikorsky, 1940, about his prototype VS-300 that would only fly backward and sideways]
The Boeing 747 is the commuter train of the global village.
[H. Tennekes, in The Simple Science of Flight, 1996]