Участник:Эйхер/Песочница: различия между версиями

In both cases the two media travel in the same direction relative to the vehicle - backwards. In the case of going upwind the air is travelling faster than the Earth and in the case of going downwind faster than wind the Earth is travelling faster relative to the vehicle. For a given force imparted by a medium to the vehicle the power delivered to or gained from the meduim is directly proportional to the velocity of the medium relative to the vehicle. Therefore, in accordance with the law of conservation of energy, in order to sustain the motion the vehicle must harvest the power from the medium that moves faster relative to the vehicle and to deliver power to the slower medium.

 

 

When the vehicle goes downwind faster than wind, the wheels are used to harvest the power impeding the motion of the vehicle and driving the rotor, who, acting as an airscrew, propel the vehicle, overcoming both the resistance of the wheels and the aerodynamic drag of the hull.