希勒XH-44 – 照片和视频

Hiller Aircraft Company was founded in 1942 as Hiller Industries by Stanley Hiller to develop helicopters. Stanley Hiller, then seventeen, established the first helicopter factory on the West Coast of the United States, located in Berkeley, California, in 1942, under the name “Hiller Industries,” to develop his design for the coaxial-rotor XH-44 美国陆军的"希勒-科普特"XH-44于1944年投入使用。1945年，它与亨利·凯撒合作，成为联合直升机公司。在战后的岁月里，联合直升机公司为军事和民用目的设计了许多创新的直升机设计，包括同轴旋翼和无尾设计，以及更传统的型号。1949年1月，一架希勒360成为第一架穿越美国的民用直升机

源： 维基百科上的希勒 XH-44

这 希勒 XH-44 was an experimental helicopter developed by Stanley Hiller Jr. in the early 1940s. It was the first successful coaxial helicopter in the United States and the first helicopter to use all-metal rotor blades. The XH-44 was designed as a proof-of-concept for Hiller’s innovative rotor system, which used counter-rotating blades to eliminate the need for a tail rotor.
The XH-44 had a two-seat open cockpit, a tubular steel frame, and a 90-horsepower Franklin engine. It made its first flight in July 1944 and demonstrated excellent stability and maneuverability. The XH-44 was later donated to the Smithsonian Institution and is currently on display at the Steven F. Udvar-Hazy Center in Virginia.