revealing view of the 1907 Cornu helicopter, with its 24hp Antoinette engine and twin, tandem disposed belt driven twin-bladed rotors. The two surfaces at the fore-and-aft extremities of the machine are stabiliser planes. As with other designers of his time, Cornu, lacking modern-day systems and component supplier support, had to improvise by using such 'off-the-shelf' items as standard bicycle wheels. (US National Archives)