ABSTRACT
Despite of the advantage on aerodynamic performance, the conventional fixed-wing aircrafts suffer from a disadvantage of takeoff and landing, which yields a fierce dependence on airports. When economy or convenience counts, it becomes increasingly difficult to accept. Indeed, the problem would be enhanced in military use. Helicopters may overcome it, yet their cruising performance (especially the efficiency) is quite poor. A configuration that synthesizes the ability of economical horizontal cruise and the ability of vertical takeoff and landing has become a focus of aircraft design nowadays.
