and the early pioneers such as Voisin and Santos Dumont had used inefficient propellers with flat aluminium blades mounted on a steel tube. The first truly efficient European propeller design was produced by Lucien Chauvière, who had studied the theory of propeller design while a student at the École des Arts et Métiers in Angers. Chauvière pioneered a sophisticated construction technique using laminations of walnut. A Chauvière propeller was used by Blériot in his flight across the English Channel, and the importance of Chauvière's contribution was recognised by his being awarded a silver medal by the Aero-Club de France. Theoretical The achievement of powered flight led to the establishment of centres for aeronautical research in many countries. In 1907 Ludwig Prandtl, who had joined the University of Göttingen university in 1904, founded the Modellversuchsanstalt für Aerodynamik der Motorluftschiff-Studiengesellschaft [society for testing aerodynamic models of powered airships ]. The University of Göttingen would become a world leader in aerodynamic research. In 1909 Henri Deutsch de la Meurthe endowed a department devoted to aeronautics at the University of Paris In France the famous engineer Gustave Eiffel performed a series of experiments to investigate the effects of wind resistance on moving bodies by dropping test apparatus down a wire suspended from the Eiffel Tower: he later built a wind tunnel at the base of the Tower, in which models of many pioneer French aircraft were tested and carried out pioneering work on aerofoil sections. Pilot training Many of the pioneer constructors started their own flying schools. Pilot training was rudimentary: although the Wright Model A used by the Wright Brothers for training in Europe had been fitted with dual control, dual-control aircraft were not generally used, and aspiring pilots would often simply be put in charge of a machine and encouraged to progress from taxying the aircraft then short straight line flights to flights involving turns. Sometimes ground handling experience was built up using special short-span machines that were incapable of flight, such as the Blériot Pinguin. Most flight training was done early in the morning or in the evening when winds tend to be low, and the time taken to qualify for a licence was greatly dependent on the weather. Popular impact Santos-Dumont's airship flights had already made him a celebrity, and while ballooning remained a popular activity for the wealthy, heavier-than-air aviation quickly became a popular spectator sport, and the major