The name Autogiro, spelled thusly and capitalized, was copyrighted by Pitcairn Co in 1923, but eventually became generic and often was used interchangeably with the lower-case autogyro.

G-1 - Wingless 2pOAg; 225hp Jacobs R-775; rotor: 40'0" length: 28'10" v: 125/x/0 (data for YG-1B). From KD-1 series.

  Kellett YG-1 [34-278] (NASA)

YG-1 1935 = POP: 1 modified commercial model [34-278].

YG-1A 1936 = Radio installed. POP: 1 [36-352].

  Kellett YG-1B

YG-1B 1937 = POP: 7 [37-635, -37/382], of which 1 became YG-1C/XR-1 and 1 later redesignated as XR-3.

YG-1C 1937 = YG-1B modified with constant-speed rotor. POP: 1 [37-378], redesignated as XR-2.

H-17 1952 = Large, jet-rotor CH flying crane developed under contract as Hughes H-17 (qv).

K-1X 1930 = 1pOAg; 40 hp Szekley, later 65hp Velie M-5; rotor: 27'8" length: 24'6". Fred Seiler. Featured an unique, single-blade, wooden rotor that see-sawed on its rotor hub. The craft suffered from structural problems and unsound aerodynamic design, so several taxi runs were made with no flights, then the project was abandoned [919N] c/n 1.

  Kellett K-2 [NC11666] (Frank Rezich coll)

K-2 1931 (ATC 437, 2-351) = 2pO/ClwMAg; 165hp Continental A-70; rotor: 41'0" span: 26'0" length: 19'6" load: 649# v: 95-100/82/10-15 range: 250 ceiling: 9000'. W Laurence LePage (K-series). Direct-drive. Side-by-side seating; convertible coupe-type top. $7,885 open cockpit, $8,255 canopied cockpit; POP: 14 [NC10766/10767, NC11666/11668, NC11683, NC11685/11687, NC11691, NC12603, NC12605, NC12615, NC12633], with some modified into K-3 and -4. Rotor design and tradename later licensed by Autogiro Co of America (Pitcairn). (2-351) for prototype only [X10766] c/n 1. [NC10767] c/n 2 restored to flying condition in 2001 by Al Letcher, Mojave CA.

K-2A 1932 (ATC 2-431) = 210hp Continental R-670. POP: 4 conversions from K-2.

  Kellett K-3

K-4 1933 (ATC 523) = 2pOlwMAg; 210hp Continental R-670; rotor: 40'6" span: 24'7" length: 19'11" load: 655# v: 110/95/0-15 range: 310. POP: 1 modified from K-2 [NC11666].

  Kellett KD-1 [X14742] (Kellett)

KD-1 1934 = 2pOAg; span: (wingless) length: 28'10". No ailerons, rudder, or elevator; directional control was through a pivoting rotor head modified under license from the Cierva invention. Folding rotor blades, required a storage area of only 29'10" long, 10'4" wide, and 10'3" high. Made the first landing of an autogyro on a rooftop, at the Philadelphia post office, May 1935 (p: Lou Leavitt). POP: 1 prototype [X14742], which became KD-1A, and 1 to AAC in 1935 as YG-1.

KD-1A 1937 (ATC 712, 2-513) = 1-2pOlwMAg; 225hp Jacobs L-4; rotor: 40'0" span: 0' length: 28'10" load: 645# v: 125/100/0-15 range: 310 ceiling: 12,000'. POP: 3; [NC15684] to AAC as YG-1A, [NC39Y], and [NC14742] converted from KD-1.

  Kellett KD-1B (Stephen Pitcairn coll)

KD-1B 1937 = 1p cargo version; load: 620# v: 127/104/0-15 range: 220. POP: 7 to AAC as YG-1B and 2 civil [NC39Y, NC15069], the latter used on first autogyro air mail route, from Philadelphia PA to Camden NJ, in 1939 [.

  Kellett KD-10

  Kellett KH-2 Mock-up minus blades (Mechanix Illustrated)

KH-2 - Chubby 8-passenger jet "skybus" project only made it as far as mock-up for a 1947 trade show display. Estimated cruise: 118.

KH-15 1954 = USN. 1pOH propelled by small hydrogen-peroxide rockets at the rotor tips; ff: 5/13/54. POP: 1 for testing by the Office of Naval Research [140957].

  Kellett YO-60 [42-13606] (Stephen Pitcairn coll, Hofstra Univ)

O-60 1942 = Similar to XR-2. POP: 7 as XO-60 [42-13604/13610], the first 6 of which became YO-60.

R-2, -3 193? = POP: 2 redesignations from YG-1B and -1C as XR-2 [37-378] and XR-3 [37-380].

  Kellett XR-8 [43-44714] (1945 Flying)
  Kellett XR-8A [44-21908]

R-8, H-8 1944 = 2p KH-1; 245hp Franklin O-405-9; rotor: 36'0" length: 23'0" v: 105/85/0 range: 470. Intermeshing rotors. POP: 1 as XR-8 [43-44714] and 1 as XR-8A [44-21908], redesignated as XH-8.