Betz was born in
Schweinfurt. In 1910 he graduated as a
naval engineer from
Technische Hochschule Berlin (Diplomingenieur Schiffbau). In 1911 Betz became a researcher at the
University of Göttingen aerodynamics laboratory, where he was awarded his
PhD in 1919 for his work on 'ship propellers with minimum loss of energy'. In his 1920 paper "Das Maximum der theoretisch möglichen Ausnutzung des Windes durch Windmotoren" ("Theoretical Limit for Best Utilization of Wind by Wind Motors") was published. His work was based on earlier studies by
Frederick Lanchester that included the first full description of
lift and
drag. The formulation was somewhat complex and had to wait for
Ludwig Prandtl's version before becoming generally useful.
Betz's law states that, independent of the design of a wind turbine, only 16/27 (or 59%) of the kinetic energy of the wind can be converted to mechanical energy. His book "Wind-Energie und ihre Ausnutzung durch Windmühlen" ("Wind Energy and its Use by Windmills"), published in 1926, gives a good account of the understanding of wind energy and wind turbines at that period. In 1926 he was appointed
professor at Göttingen. In 1936 he succeeded Ludwig Prandtl as director of the
Aerodynamische Versuchsanstalt (AVA, aerodynamics laboratory), a position he held until 1956. During
World War II he developed the
Messerschmitt swept wing, as well as other war devices for the
Luftwaffe. There are also sources tying him to the development of wind turbines, in a plan to establish a German rural population in the east, replacing the Slavic population. In early 1945 he participated in the attempt to evacuate the
Z4 (computer) to the AVA under his supervision. From 1947 to 1956 he also headed research into
hydrodynamics at the
Max Planck Institute. He was the great-uncle of the author Alfred J. Betz from
Philadelphia, and great-nephew of
Vladimir Alekseyevich Betz the discoverer of the
pyramidal cell. Betz died in
Göttingen, aged 82. ==Recognition==