content: I agree with your skepticism. It appears to be petrol powered, and to be fair there are videos showing the prototype generating significant lift unassisted. And actually, the amount of force generated by four rotters even with a small engine could be sufficient for low sustained flight. From an engineering point of view, the design and the concept are far from unrealistic. The unrealistic part is the licensing and regulation of this kind of small personal helicopter. Much like the Moller skycar - it will probably work just fine - except that it will be completely illegal.