return expected rate of turn in degrees/s for given speed in m/s and
       bank angle in degrees

def rate_of_turn(speed, bank):
    '''return expected rate of turn in degrees/s for given speed in m/s and
       bank angle in degrees'''
    if abs(speed) < 2 or abs(bank) > 80:
        return 0
    ret = degrees(9.81*tan(radians(bank))/speed)
    return ret