Two families and a Spanish patent

W. Wallace Kellett and C. Townsend Ludington founded the company in Philadelphia in 1929 with their brothers Rodney Kellett and Nicholas Ludington. In 1931 they licensed the autogiro patents of Juan de la Cierva and Harold Pitcairn, and their first three machines were textbook Cierva types. The K-2 utility autogiro flew in 1931 and a dozen were built.

Mail on the post office roof

The breakthrough was the KD-1 of 1934, similar to the Cierva C.30, steered entirely through its rotor with no ailerons or elevators. Kellett’s own test pilots distrusted it and refused to fly it, so the firm hired autogiro specialist Johnny Miller. In 1935 the US Army bought one as the YG-1, its first practical rotary-wing aircraft, and later ordered more as observation machines. On 6 July 1939 Eastern Air Lines used a KD-1B to open the first scheduled rotary-wing air mail service, between Camden airport and the roof of Philadelphia’s main post office.

The egg-beater

Sikorsky’s VS-300 turned the Army towards helicopters, and Kellett followed. Its XR-8 of 1944, with two intermeshing three-bladed rotors that earned it the nickname egg-beater, proved the twin-rotor idea though its blades once collided in flight. The larger XR-10 followed in 1947. Kellett stopped building autogiros in the late 1940s and ended with ultralight test helicopters and the K-25 tilt-rotor convertiplane project in the 1950s.

الناس

• دبليو. والاس كيلت · المؤسس المشارك
• Johnny Miller · chief test pilot — Flew the KD-1 when staff pilots refused; later flew the mail for Eastern
• Dave Driskill · chief test pilot — First flew the XR-8 in 1944

الأرقام القياسية والأولويات

• First practical rotary-wing aircraft used by the US Army, KD-1 as YG-1, 1935
• First scheduled rotary-wing air mail service, Eastern Air Lines KD-1B, 6 July 1939