3 ms·

I find it extremely counterintuitive, especially this part: In 2012, Blackbird also demonstrated sailing directly upwind with twice the speed of the wind.[0]

• marcan_42 5y ago
  I posted an explanation for the downwind version above, but here's the gist of why all this is possible: To extract energy from the wind, you need a reference that is slower than the wind. The ground is one such reference. The vehicle gets access to that reference via the wheels. It can therefore extract power from the wind regardless of where it's going or what it's doing. So it's like a wind turbine on the ground, connected to a car that has nothing to do with it. Of course the car can go faster than the wind in this situation; the wind speed doesn't matter, only the drag of the car and how big your wind turbine is (how much energy you can get out of it). This vehicle just makes the whole thing self contained with gearing and counterintuitive rotation of the propeller. It's touching the ground and can use that reference via the wheels, so it can pretend to be a stationary wind turbine on the ground this way. That means it can go downwind, or upwind; doesn't matter. As long as the wind is moving relative to the ground, it can harness that energy.