A rotor model of radius 0.40 m produces the desired aerodynamic performance while rotating at 300 rpm. A full-size rotor, geometrically similar and of radius 4.0 m, is to be tested under dynamically similar conditions in the same air. Approximately what speed should the full-size rotor be run at?
a) 30rpm
b) 9.5rpm
c) 3rpm
d) 95rpm