The turboprop tailsitter concept emerged in the late 1940s, with the US Navy Bureau of Aeronautics (BuAer) beginning to seriously examine the feasibility of developing a vertical take-off and landing (VTOL) tailsitter aircraft to protect convoys, task forces, and other vessels. These specialized interceptors would be placed on the decks of ships to provide a rapid defensive and reconnaissance capability until conventional carrier-based fighters could arrive and assist. The Battle of the Atlantic was fresh in the minds of Navy planners, who were concerned that the Soviets would engage in a similar campaign against merchant shipping if the nascent Cold War erupted into open conflict. BuAer’s interest in a VTOL tailsitter fighter coincided with the development of new turboprop engines which provided enough horsepower to make the concept a reality.
BuAer’s Outline Specification for Class VF Airplane (Convoy Fighter) OS-122 was dated July 10, 1950. It listed the requirements for such an aircraft along with a scale demonstrator to verify the soundness of the concept. The document was distributed to the major aircraft manufacturers of the day, with the Lockheed, Convair, Goodyear, Northrop and Martin responding.
Lockheed and Convair were selected and given a contract to produce two prototypes each. These aircraft never made it beyond the prototype stage, as they proved to be very difficult to land, suffered from power plant reliability issues, and were eclipsed in performance by contemporary jet fighters.
Convair Model 5 XFY-1 Pogo
Goodyear Model 28B XF3G-1
Lockheed model 081-40-01 XFV-1 Salmon
Martin model 262 XFM-1
Northrop model N-63 XF3T-1
Convair XFY-1 Pogo - KP
Goodyear 28B - Fantastic Plastic
Lockheed XFV-1 - Valom
Martin M262 - Fantastic Plastic
Norethrop N63 - Fantastic Plastic