(September 2011) In 1920 it was already common knowledge among pilots that, as airplanes got very close to the ground, they seemed to slide along on a slippery cushion of air. A decade later, the phenomenon — “ground effect” — had been investigated in wind tunnels and flight tests and was well documented, even if the precise mechanisms involved were still imperfectly understood. A 1934 summary of existing research by a French investigator, Maurice Le Sueur, was translated by the National Advisory Committee for Aeronautics, NASA’s wonderfully productive and helpful predecessor, and published as Technical Memorandum 771 under the title “Ground Effect on the Takeoff and Landing of Airplanes.”
“Observations on airplanes in free flight,” Le Sueur wrote, “have enabled us to observe certain systematic phenomena such as: the greater facility of low-wing airplanes for taking off; the impossibility of certain heavily loaded airplanes to gain altitude; the prolonged gliding power of low-wing airplanes at landing, etc.”
