9.33 An airplane with an effective lift area of 25 m2 is fitted with airfoils of NACA 23012 section (Fig. 9.23). The maximum flap setting that can be used at takeoff corresponds to configuration in Fig. 9.23. Determine the maximum gross mass possible for the airplane if its takeoff speed is 150 km hr at sea level. Find the minimum takeoff speed required for this gross mass if the airplane is instead taking off from Denver (elevation 1.6 km).