Originally the first YH-40, redesignated YHU-1B and then YUH-1B, this early Huey was rebuilt for high-speed research. It is fitted here with a pair of additional J69 engines. Wings were also added later on. In 1969 it reached a speed of 509 km/h (316 mph). Photo from: US Army / Wright State University
This photo was added on 29 July 2021, and has since been viewed 354 times.