Vertol VZ-2 - (scan - 1997)

Produced under Army/Navy contract to develop tilt-wing (wing and rotors rotate as unit) concept. Center-mounted engine drove 2 3-bladed rotors through gear train; 2 ducted fans at the tail--1 rotating in horizontal plane and the other rotating in vertical plane--provided pitch and yaw control at low speeds. Aircraft successfully transitioned during tests c. 1958-9. Power adequate, and pilot John Reeder completed a number of successful transitions from vertical takeoff to horizontal flight and from horizontal flight to vertical flight and vertical landing. Later flight tests explored limits of operation near ground and established minimum and maximum speeds/ rates of descent (or climb) for safe operation. An unusual observation during the latter tests was "negative" ground effect. During descent, aircraft would experience sharp increase in rate of descent as aircraft approached ground; conversely, during low-speed ascents, aircraft experienced reverse effect-- notable increase in rate of climb as it got out of ground effect. VZ-2 program developed some significant parameters which guided designs of subsequent VTOL aircraft. A tilt-wing transport design carrying 14 passengers powered by 2 2,200 hp turboprop engines was being investigated under joint development program between DMAV, Inc., Arlington TX, and Ishida Group of Nogoya, Japan. DMAV claimed tilt-wing design, explored in detail during 50s and 60s, allows use of relatively simple propeller-type rotor, while tilt- rotor design (e.g., V-22 Osprey) requires more complicated helicopter-type rotor with attendant complexities. Project abandoned c.1994.

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