It's very hot in the UK at the moment, and so I went out and bought a semi-industrial 20" pedestal fan for my living room. It certainly does its job in cooling, but unfortunately, it also sounds like a jet engine. This got me wondering. I assume it uses a standard brushless electric motor to avoid friction, so where is the noise coming from? (I know that it's not coming from the blades whirling, because I removed them, and just heard the engine noise). Is it possible to engineer an electric motor to avoid the noise completely, and would room-temperature superconductors (if and when they become available) immediately solve the problem? Searching the web produced surprisingly few answers, but it would be profound for humanity if we could create a silent engine.