On 14th January 1942 (or 13th January, according to some sources), a helicopter designed by Igor Sikorsky and designated Vought-Sikorsky VS-316 (aka XR-4, under its USAAF designation) performed its maiden flight, piloted by Les Morris, Sikorsky´s test pilot. A few months later, the XR-4 was approved by the US Army and became the first serial manufactured helicopter in the USA and the first one operationally used by the Allied forces in the World War II.
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Cover photo: One of Langley’s Sikorsky YR-4B/HNS-1 helicopters is seen in the 30 x 60 Full Scale Tunnel. The technician is setting up camera equipment for stopped-action rotor-blade photos. Source: NASA, Image # L-40416, via Flickr Commons.
