def Rmax_Q11(Vmax):
    """ Estimation of the radius of maximum wind according to the formula proposed
    by Quiring et al. (2011); Vmax and Rmax are in nautical miles. 
    Expression herein converted in km"""
    Vm= Vmax * 0.5399568
    Rmax = ((49.67 - 0.24 * Vm)) * 1.852 
    return Rmax