autogyro v. helicopter
Sunday, November 22, 2009 
Autogyro An autogyro (also spelt ‘autogiro’, and sometimes called a gyroplane or gyrocopter) is a type of rotorcraft having a front- or rear-mounted powered propeller, which provides thrust, and an unpowered, autorotating rotor, which provides lift. The autogyro was invented by Juan de la Cierva and first successfully flown in 1923.
By comparison, a helicopter has no propeller, and both thrust and lift are generated by one or more engine-powered rotors.
Unlike a heliopter (but like almost all other fixed-wing aircraft), an autogyro has to move forward to develop lift, so it can’t hover. It does, however, require a dramatically smaller runway than an airplane would, and can fly at very low speeds. In addition, autogyros can fly faster than helicopters, which stall at high speeds. Autogyros are constructed more simply than helicopters, which tends to make them lighter. Lastly, in the event of engine failure, an autogyro’s forward velocity ensures that autorotation will continue to generate lift, allowing the craft to land gracefully.