Comments by "bruzote" (@bruzote) on "Risking My Life To Settle A Physics Debate" video.

@Cryseris - I believe the video includes a comment that it is not only possible, but has been done! That is a bit mind-bending to me as well. I am humbled by these sailcraft videos.
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@gl0wingice - Ah, but the "trick" of exceeding downwind air speed is being explained using a similar trick for tacking sailboats. I am interested in how a tacking boat can achieve a downwind speed exceeding the downwind air speed (horizontal speed of a free balloon). It seems the boat gains energy by constraining the direction of flow. From a conservation of momentum standpoint, it seems possible but I can't say certainly it should happen. After all, momentum and energy are different things.
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No, that is not. Feathering is when the propeller blades are turned so a dead prop is able to slice through the wind with minimal drag. Without feathering, a prop blade on a dead engine is like a flat board pushing against the air. You don't want to waste energy like that, especially when you've just lost the use of a propeller.
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In your analogy, what would be the ground surface that is used to drive the spacecraft?
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@191246mann1 - People can delete their own replies, which some do after they realize they were wrong (or for other reasons, like regretting rudeness or unjustified allegations against others). I've done that myself at times. Sometimes, it is because incorrect replies can mislead others, especially on YouTube where the comments are not fully hierarchical. Other times, I have been an offensive fool and simply saw no reason to leave up a comment that was offending others.
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I believe you are referring to the end of the video, in which it seems the car is turned away from the downwind direction and towards the waiting trailer and crew. You can the call for direction change (full tack, full tack). As for the professor, if he was wise enough to not make a losing bet if he wanted to make, perhaps he was not trying to make money. Maybe he was willing to donate money to get attention to the video.
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