XV-15 litho - NASA's History Office

Figure 4.
McDonnell XV-1
compound helicopter.
(Boeing Photograph
AD98-0209-13)
Figure 5.
Sikorsky XV-2
Convertible Aircraft.
4
Early Efforts
For one group of military planners in the late 1940s and early 1950s, the mission
requirements included significant hover duration, low speed maneuvering and
agility, and a speed and range greater than current helicopter capabilities. This, and
additional mission factors such as the need for moderate downwash velocities
below the hovering aircraft to enable safe rescue operations, led the planners to
specify low disc loading for the new VTOL vehicle. These considerations resulted
in the August 1950 initiation of the joint U.S. Army and U.S. Air Force
Convertiplane Program. This program was formulated to provide demonstrations
of different approaches to meeting the convertiplane requirements. The aircraft
selected from the design competition were the XV-1 compound helicopter, figure 4
(proposed by the McDonnell Aircraft Co.), the XV-2 stoppable rotor aircraft, figure
5 (proposed by Sikorsky Aircraft), and the XV-3 tilt rotor aircraft, figure 6 (submitted
by the Bell Helicopter Company). A discussion of the aircraft concepts
addressed in the Convertiplane Program is provided by R. W. Prouty’s February
1984 Rotor and Wing International article “From XV-1 to JVX—A Chronicle of
the Coveted Convertiplane.”
Two designs, the XV-1 and the XV-3, survived the initial evaluation phase and
were developed as test aircraft for limited flight evaluations. While the XV-1