Boeing B-50 Superfortress

KB-50s were B-50 bombers modified as aerial tankers, generally after they had become surplus to Strategic Air
Command requirements.

These alterations involved the removal of armament and the installation of additional fuel tanks and probe-and-drogue
equipment to permit the aerial refueling by hose of up to three fighter-type aircraft at one time.

KB-50s went into service with the Tactical Air Command in 1957. As the performance of operational jet fighters increased, a J47 jet engine was installed under each wing on some KB-50s to boost speed while refueling and to increase altitude capability. Hayes Aircraft Corporation converted 136 tankers in this manner (KB-50Js and Ks).

Deliveries of these improved tankers to TAC began in early 1958.

They were replaced by jet KC-135 tankers in the mid-1960s, but a few were still available in 1965 for use in Southeast
Asia for emergency refueling of fighters over hostile territory.

All 24 TB-50H aircraft were modified initially to KB-50 configuration and later to K models after the addition of two J47 turbojets.

The primary reason the 136 KB-50s (112 from B-50D and 24 from TB-50H) were redesignated J and K models was to distinguish the aircraft for maintenance purposes.

The differences between the D and H model were significant enough to warrant separate maintenance manuals.