The last time something about this was posted on HN there were a lot of comments about them taking advantage of the ground effect: http://en.wikipedia.org/wiki/

The last time something about this was posted on HN there were a lot of comments about them taking advantage of the ground effect: http://en.wikipedia.org/wiki/Ground_effect_(aircraft) http://en.wikipedia.org/wiki/Ground_effect_(aircraft) Apparently a lot of the aircrafts flying capability has to do with its proximity to the ground. I'm sure part (if not all) of the reason why the rotars almost touch the ground. It seems that you're certainly right, they're not creating a fully functioning flying machine, they're building a challenge winner, and that's what they set out to do.