Kellett KD 1

Development

Using the experience gained in building Cierva autogyros under licence the Kellett Autogiro Company developed the KD-1 which was similar to the contemporary Cierva C.30. It had two open cockpits, a fixed tailwheel landing gear and was powered by a 225 hp (168 kW) Jacobs L-4 radial engine. After testing of the prototype a commercial variant designated the KD-1A was put into production. The KD-1A had a three-bladed rotor with folding blades and a number of minor detail improvements. A KD-1B which was a KD-1A with an enclosed cockpit for the pilot was operated by Eastern Airlines and inaugurated the first scheduled rotary-wing air-mail service on 6 July 1939.

In 1935 the United States Army bought a KD-1 for evaluation and designated it the YG-1, a second aircraft followed which had additional radio equipment and was designated the YG-1A. These two aircraft were followed by a batch of seven designated YG-1B. In 1942 seven more were bought for use in the observation role as the XO-60. Six XO-60s were re-engined with 300 hp (224 kW) Jacobs R-915-3s and re-designated YO-60. One YG-1B was modified with a constant-speed rotor and was re-designated the YG-1C, it was later re-engined with the more powerful R-915 and re-designated again as the XR-2. The XR-2 was destroyed by rotor ground resonance problems and the evaluation was continued with another modified YG-1B designated the XR-3.

Variants

KD-1

Prototype, one built

KD-1A

Commercial variant with open cockpit and a 225 hp (168 kW) Jacobs L-4 radial engine; three built.

KD-1B

Commercial variant with enclosed cockpit; two built.

YG-1

United States Army designation for one KD-1A acquired for evaluation.

YG-1A

One aircraft as YG-1 with the addition of radio equipment.

YG-1B

Production aircraft for the United States Army; seven built.

YG-1C

One YG-1B modified with a constant-speed rotor for evaluation, later designated the XR-2.

XO-60

Production aircraft for the United States Army with a 225 hp (168 kW) Jacobs R-755 radial engine, seven built.

YO-60

Six XO-60s re-engined with a 300 hp (220 kW) Jacob R-915-3 radial engine.

XR-2

The YG-1C re-designated after being re-engined with a 300 hp (220 kW) Jacobs R-915-3 radial engine.

XR-3

One YG-1B modified to XR-2 standard for evaluation.

Kayaba Ka-Go prototype

Prototype, based on a KD-1A airframe repaired by Kayaba.

Kayaba Ka-1

Imperial Japanese Army development of the Ka-Go, powered by a 240 hp (180 kW) Argus As 10 engine.

Kayaba Ka-2

Imperial Japanese Army development of the Ka-1, powered by a 245 hp (183 kW) Jacobs L-4MA-7 engine.

Operators

 United States

Eastern Airlines

United States Army Air Forces

Specifications (KD-1B)

General characteristics

Crew: 2

Length: 28 ft 10 in (8.79 m)

Performance