On October 14, 1960, the United States Navy solicited response from 25 aircraft manufacturers to a request for proposals (RFP) on behalf of the Army for the Light Observation Helicopter (LOH). Bell entered the competition along with 12 other manufacturers, including Hiller Aircraft and Hughes Tool Co., Aircraft Division. Bell submitted the D-250 design, which would be designated as the YHO-4. On May 19, 1961, Bell and Hiller were announced as winners of the design competition.
YOH-4A LOH in flight
Bell developed the D-250 design into the Bell 206 aircraft, redesignated as YOH-4A in 1962, and produced five prototype aircraft for the Army's test and evaluation phase. The first prototype flew on December 8, 1962. The YOH-4A also became known as the Ugly Duckling in comparison to the other contending aircraft. Following a flyoff of the Bell, Hughes and Fairchild-Hiller prototypes, the Hughes OH-6 was selected in May 1965.
When the YOH-4A was eliminated by the Army, Bell went about solving the problem of marketing the aircraft. In addition to the image problem, the helicopter lacked cargo space and only provided cramped quarters for the planned three passengers in the back. The solution was a fuselage redesigned to be more sleek and aestheticly appealing, adding 16 cubic feet (0.45 m3) of cargo space in the process. A Bell executive contributed to this redesign by drawing on a sketch two lines extending the fuselage to where it meets the tail. The redesigned aircraft was designated as the Bell 206A, and Bell President Edwin J. Ducayet named it the JetRanger denoting an evolution from the popular Model 47J Ranger.