This simple, practical, foolproof personal helicopter coupe is big enough to carry two people and small enough to land on your lawn. It has no carburetor to ice up, no ignition system to fall apart or misfire: instead, quiet, efficient ramjets keep the rotors moving, burning any kind of fuel from dime-a-gallon stove oil or kerosene up to aviation gasoline
GREGORY BENFORD, Popular Mechanics, (2012), "The Future That Never Was: Pictures from the Past', [online], Available: http://www.popularmechanics.com/technology/engineering/future-that-never-was-next-gen-tech-concepts?click=main_sr#slide-1
http://www.popularmechanics.com/technology/engineering/future-that-never-was-next-gen-tech-concepts?click=main_sr#slide-32