sentences:  Akaflieg
  
  Akaflieg is an abbreviation for "Akademische Fliegergruppe", groups of aeronautical engineering students from individual German Technical Universities, pre and postwar, who design aircraft, often gliders.Otto Lilienthal published his book "Der Vogelflug als Grundlage der Fliegekunst (Birdflight as the Basis of Aviation)" in 1889.