A bit cheap, but generally correct answer: how could *this* be?
The keyword is "drawing". It seems that it is the drawing that represents the general idea, not all the details and technical solutions. Also note that at least I cant see there any shaft from the engine to the rotor.
Thanks Matej, I had not noticed the window at the rear of the cockpit, with no shaft there nor below the rotor.
Well, I imagine a solution: in fact the engine and propeller axis were one or two feet higher, with a direct (almost horizontal) link to the rotor, and just the blade tips needed a hole to rotate freely thus lateral booms. The artist made it wrong, but maybe more pretty, this is art... No?
Though it would be a bit corny, there is another possibility: the propeller at the back tilts underneath the fuselage when in the air, working as an counter-rotating rotor. When landing, it stops and tilts back between the booms...
Your idea is fascinating, yes! ???
While... I doubt the length is big enough for the blade above to go down without breaking the tailplane, or even the boom/tail contact if the blade is set at 45° (or 60°) before the moving occurs.
But this looks like brainstorming for us. Very pleasant, thanks a lot! ;D