Let C be a cylinder positioned at the center of the propeller with the same radius as the propeller and whose length = the velocity of the wind. Based on the de

Let C be a cylinder positioned at the center of the propeller with the same radius as the propeller and whose length = the velocity of the wind. Based on the density of the air and the volume of air contained in the cylinder and velocity of the wind we can calculate the total momentum available. There are theorems on how efficiently you can extract this energy - based on propeller theory. let this number be defined as "eta". if M * V * eta is the momentum available and the mass of the vehicle is less that M * eta where M * V * eta is the momentum extracted i.e. m < M * eta - then the velocity of the vehicle "v" must be greater than V the velocity of the wind. If you notice the size of the propeller in the picture - it is huge - so that the mass of the wind it intercepts > than the mass of the vehicle