... well as the Sussex police/hospital helicopter. Flight 'Heavier than air' flying machines must have someway of taking off from the ground; they must be self-propelled, and must have some way to create lift, (aeroplanes have wings, and helicopters have rotor blades). There are two main ways for wings to create lift; The Longer Path, (Bernoulli or equal transit time) explanation and the Newtonian, (momentum transfer or deflection) explanation. The longer path explanation works on the theory that if an object hits air, all particles of air passing around the object will meet again on the other side. This means that if an object is shaped in a particular way so that the top side of the object is longer from front to back than the underside, then when particles of air go above and below the object the fact that particles above the wing are travelling faster than the ones below it means ...

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