The the design of their kite and full-size gliders on work done in the 1890s by other aviation pioneers. They adopted the basic design of the Chanute-Herring biplane hang glider ("double-decker" as the Wrights called it), which flew well in the 1896 experiments near Chicago, and used aeronautical data on lift that Otto Lilienthal had published. The Wrights designed the wings with camber, a curvature of the top surface. The brothers did not discover this principle, but took advantage of it. The better lift of a cambered surface compared to a flat one was first discussed scientifically by Sir George Cayley. Lilienthal, whose work the Wrights carefully studied, used cambered wings in his gliders, proving in flight the advantage over flat surfaces.