XV-15 litho - NASA's History Office

Figure 35.
Illustration of the Boeing
Model 222 tilt rotor aircraft.
(Boeing-Ames Photograph
AC86-0140-1)
36
empennage configuration to improve the directional stability characteristics.
Boeing provided a proposal based on the new Model 222. This design used the
Boeing-developed 26-foot diameter soft-in-plane hingeless proprotor on nacelles
that tilted only the proprotors. The engines of the 222 were mounted in fixed
horizontal wing-tip nacelles. To minimize research aircraft development costs,
the Boeing 222 was to use the fuselage, landing gear, and empennage of the
Mitsubishi Mu-2J twin turboprop executive transport aircraft. The 222 wing
incorporated leading edge “umbrella” flaps and large deflection trailing edge
flaps to reduce download. An artist’s illustration of the Boeing 222 in flight is
shown in figure 35.
A Source Evaluation Board (SEB) was convened to evaluate the proposals. In
accordance with procurement regulations, the outcome of the competition was to
be determined by the Evaluation Criteria defined in the RFP. These consisted of
the Mission Suitability Factors which were scored, and “other factors” which
were evaluated but not scored. The Mission Suitability Factors were comprised
of Design, Implementation, and Management components. The other factors that
were rated but not scored were: cost, company past performance, financial capability,
and the new-technology plan.