“Gradual development of flight should begin with the simplest apparatus and movements, and without time complication of dynamic means.”Otto Lilienthal The Romance of Aeronautics (1912)
“The sailing flight of birds is the only form of flight which is carried on for some length of time without the expenditure of power.”Otto Lilienthal The Romance of Aeronautics (1912)
“The supporting powers of time air and of the wind depend on the shape of the surfaces used, and the best forms can only be evolved by free flight through the air.”Otto Lilienthal The Romance of Aeronautics (1912)