Kit #AA2011. 1/72 scale. Highly-detailed resin kit with decals. During early 1955, Hiller Aircraft designed a large, tilt-wing VTOL aircraft as an in-house study. In 1956, the U.S. Air Force became interested in the concept and assigned a contract to Hiller to further develop the VTOL cargo transport. The test bed was designated X-18. In order to speed the construction process and to conserve available Air Force funding, the X-18 was built from many existing materials, including the fuselage from Chase C-122, the turboprops engines from the XFV-1 and XFY-1, miscellaneous parts from the R3Y. The prototype was completed and started to proceed with ground testing in 1958. A year later, it made first flight without any difficult. After a total of 20 flights were completed, the Air Force ended its flight-testing and set it aside for ground tests to develop a database for the upcoming XC-142 transport project. In 1964, the X-18 was disassembled for scrap.