Abstract
Everyone involved in the field of wind energy research and utilization is familiar with the so-called Betz limit. It defines an upper limit to the amount of energy in the wind that can be converted to effective power. The original derivation of this limit has been attributed to Albert Betz, a pupil and colleague of Ludwig Prandtl at Goettingen University in Germany.
However, the English engineer Frederick William Lanchester published more than five years before exactly the same result as derived later by Betz. And yet, there is no reason to believe that Betz would deliberately to acknowledge Lanchester's earlier derivation if he was aware of it. It is interesting to consider whether or not the earlier deviation might have been known to Betz.
In view of the circumstances affected by World War I, the authors propose that the so-called Betz limit be referred to in the future as the Lanchester-Betz limit. For Lanchester, it will be a well deserved tribute to a scientist who helped lay the foundation for our present understanding of wind turbine rotor aerodynamics.
