Kellett KD-1

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Kellett KD-1
Kellet YG-1B Autogyro (37-381 - N37380) (25340902763).jpg
Kellett XR-3 modification of YG-1B (KD-1) of U.S. Army preserved at Yanks Air Museum, Chino airfield California, on February 2016
RoleAutogyro
National originUnited States
Manufacturer Kellett Autogiro Company
First flight 1934
Primary users United States Army Air Forces
Eastern Airlines
Developed into Kayaba Ka-1/Ka-2

The Kellett KD-1 was a 1930s American autogyro built by the Kellett Autogiro Company. It had the distinction of being the first practical rotary-wing aircraft used by the United States Army and inaugurated the first scheduled air-mail service using a rotary-wing aircraft.

Contents

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. The D in the KD-1 designation stood for Direct control, meaning that the rotor was responsible for all control of the machine, so ailerons, wings and elevators were not necessary. [1] This caused distrust from Kellett's test pilots, who refused to fly it. Kellett then hired Johnny Miller, who thoroughly understood autogyros, as chief test pilot. After successful testing of the prototype, it was converted into a mail-carrying variant designated the KD-1A which had the front cockpit converted into a baggage compartment and was put into production. It had a three-bladed rotor with folding blades and a number of minor detail improvements. A KD-1B was a development of the KD-1A, with an enclosed cockpit for the pilot, radio, blind-flying instruments and a landing light, and was ordered and operated by Eastern Air Lines, who hired Miller to fly it.

They inaugurated the first scheduled rotary-wing air-mail service on 6 July 1939 between Camden Central Airport and Philadelphia's main Post Office. [2]

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. [3] 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

YG-1 (KD-1) at Langley Kellett YG-1 at Langley April 1936.jpg
YG-1 (KD-1) at Langley
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, one converted from the KD-1.
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 at Langley Kellett YG-1B at Langley - NASA image L-16653.jpg
YG-1B at Langley
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.
A Kellett XO-60 XO-60.jpg
A Kellett XO-60
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
Based on a KD-1A airframe repaired by Kayaba.

Operators

Flag of the United States (23px).png  United States

Specifications (KD-1B)

General characteristics

Performance

See also

Related development

Aircraft of comparable role, configuration, and era

Related lists

Related Research Articles

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<span class="mw-page-title-main">Juan de la Cierva</span> Spanish engineer and count (1895–1936)

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<span class="mw-page-title-main">Cierva C.30</span> 1933 autogyro family by Cierva

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<span class="mw-page-title-main">Cierva C.8</span> Type of aircraft

The Cierva C.8 was an experimental autogyro built by Juan de la Cierva in England in 1926 in association with Avro. Like Cierva's earlier autogyros, the C.8s were based on existing fixed-wing aircraft fuselages – in this case, the Avro 552.

<span class="mw-page-title-main">Cierva C.17</span> Type of aircraft

The Cierva C.17 was a British experimental autogyro built by Cierva Autogiro Company in England in 1928, in association with Avro. It was an attempt to build upon the successful Cierva C.8 design using the smaller, more streamlined fuselage of an Avro Avian IIIA as a starting point. The type was found to be underpowered, and when the first attempt at fitting a more powerful engine still did not result in acceptable performance, the design was abandoned.

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<span class="mw-page-title-main">Kellett Autogiro Corporation</span> US aircraft manufacturer

The Kellett Autogiro Corporation was an American aircraft manufacturer from 1929 based in Philadelphia, named after founder W. Wallace Kellett.

<span class="mw-page-title-main">Kellett K-2</span> Two-seat autogyro

The Kellett K-2 was a two-seat autogyro developed in the United States in the early 1930s. Later examples were designated K-3 and K-4 when equipped with more powerful engines. K-3 NC 12691 is seen in the 1934 movie, It Happened One Night.

<span class="mw-page-title-main">Kellett XR-8</span> Type of aircraft

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<span class="mw-page-title-main">Pitcairn PA-34</span> Type of aircraft

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<span class="mw-page-title-main">Pitcairn PCA-2</span> Type of aircraft

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The Westland CL.20 was a two-seat autogyro designed and built by Westland Aircraft between 1934 and 1938. One flying prototype and six airframes were built, which had control problems and insufficient lift. Before these problems could be solved the programme was abandoned and the prototype was scrapped in 1938.

<span class="mw-page-title-main">Buhl A-1 Autogiro</span> Type of aircraft

The Buhl A-1 Autogiro was an autogyro optimised for air camera work designed and built from 1930. To this end, Etienne Dormoy designed the Buhl A-1, an autogyro with a pusher engine located behind the pilot and camera operator. The Buhl A-1 was the first pusher style autogyro. It is now on display at the Hiller Aviation Museum in San Carlos, California.

<span class="mw-page-title-main">Johnny Miller (aviator)</span> American aviator, autogyro pioneer, and airline pilot

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<span class="mw-page-title-main">Pitcairn PA-22</span> Type of aircraft

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References

Notes

  1. "Kellett KD-1". All the World's Rotorcraft. Retrieved 24 May 2020.
  2. Lewis, W. David. "The Autogiro Flies the Mail! Realising the dream of flight pp 79-81" (PDF). NASA History. Retrieved 24 May 2020.
  3. "ARMY AUTOGIRO" Popular Science, June 1944, photo of YO-60

Bibliography

Commons-logo.svg Media related to Kellett KD-1 at Wikimedia Commons