I have noticed that on commercial aircraft all the windows have what appears to be a tiny hole in, presumably, the inner skin at the bottom of the window. What is this for?
A lot of commercial diesels spend their working lives runnning continuously for very long periods which is ideal for longevity. They don't do stop-start motoring with attendant cool-hot-cool cycles like so many gasoline engines
Is the paint on an aircraft aerodynamically necessary, or necessary for the protection of the skin of the aircraft? I'm just wondering how much a typical paint covering for, say, a 747 weighs. Are the passengers paying so that the airline can fly a ton(?)of advertising hoarding on every trip?