. . . "Development of the X-27 began in mid 1961, when Clarence L. 'Kelly' Johnson, head of Lockheed's advanced development projects office, initiated an in-house study to create an improved, yet relatively unchanged, long term replacement for the F-104 Starfighter. This eventually led to the CL-1200, the design of which was frozen in 1971."@en . . . . "Lockheed X-27"@en . . "Development of the X-27 began in mid 1961, when Clarence L. 'Kelly' Johnson, head of Lockheed's advanced development projects office, initiated an in-house study to create an improved, yet relatively unchanged, long term replacement for the F-104 Starfighter. This eventually led to the CL-1200, the design of which was frozen in 1971."@en . . .