Comments by "" (@timogul) on "driving 4 answers" channel.

I could see how you could use "extremely slim gaps" if we were talking a consistent distance, like if the vanes stayed extended the entire time, but I don't understand how it would ever work with constantly shifting vane lengths. If it only barely touched at the two apogees, it would still be grinding against the walls the entire rest of the rotation. If you're trying to say that it would precisely extend and retract to the exact size needed at ever possible millisecond, I just think that's extremely unrealistic. It might be possible for a multi-million dollar gadget that needs to be very precise and worth using it for that, but never something that could be scaled down to a commercial auto. One possible solution I could think of though would be if the vanes themselves were geared in some way so that they just automatically extended and retracted as the unit spun, similar to one of those antique toys with a wooden crank that causes four blocks to extend and retract as you crank it. I think perhaps there would be a lot of strain in such a system, however, and it might be difficult to get the extreme tolerances needed.
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