Leonardo drew many flying machines. Discover for yourself which of these two will fly like a bird or sink like a stone, and why.
Humankind has always envied the birds their freedom of the skies, so it was only natural that we should try to fly like them. Unfortunately, as both Leonardo and countless others discovered, it’s not possible for humans to fly in this way.
Even if we strap on a pair of “wings” and flap our arms around a lot, we lack the necessary upper body strength to provide the power needed to lift off the ground – or avoid a painful and often fatal collision with it.
With a fixed wing or aerofoil, however, we have a much better chance of achieving flight.
The shape of the aerofoil means that air passes over the top of it at a greater speed than it passes under it. This greater speed results in a drop in pressure on the top of the wing, generating lift.
Having passed over the aerofoil the air is then deflected downwards. This downwards push of air is balanced by a matching upwards force.
Conveniently, this was described by Sir Isaac Newton in his Third Law, which states crudely that for every action there is an equal and opposite reaction. This equal and opposite reaction provides the additional push necessary to get the craft into the air and keep Leonardo out of the water.