On an average, we can say either hydro static pressure acting on the propeller is at the shaft center line, where you have half the blade above half the blade below. But locally the hydrostatic pressure is low at the top and high at the bottom, this is a very broad indication of pressure variation. On top of it we will impose the hydro dynamic pressure. We have seen yesterday that the propeller generates high pressure on the face and low pressure on the back. Have we seen that yesterday, isn’t it? So, and that is how you get the lift by pressure variation.