As mentioned in the previous post in this series, early in 1953 two B-47Bs were converted for trials with the British-developed hose-and-drogue aerial refuelling system. One of them was to be a tanker, the other the receiver. The tanker was redesignated KB-47G, and the receiver was redesignated YB-47F.
The KB-47G was a single B-47B (serial number 50-040) modified as a experimental hose tanker for the refuelling of the YB-47F which was fitted with a refuelling probe in its nose. During the refuelling operation, a hose and drogue system was unreeled from the bomb bay of the KB-47G, and the YB-47F would fly below and behind and use a nose probe to engage a basket trailed from the end of the hose.
The method did not prove to be practical for the inflight refuelling of the B-47, and the established flying boom system was used for the refuelling of subsequent models.
The Stratojet tanker concept was briefly revised in mid-1956, when it was found that the KB-50s of the Tactical Air Command lacked the speed and altitude performance to refuel the new Century Series fighters. On July 23, 1956, the Air Force authorized the development of a KB-47 two-drogue prototype tanker. However, the cost of the KB-47 conversion promised to be excessively high, and it was found that the addition of two auxiliary jet engines to the KB-50 provided a satisfactory albeit temporary solution to the speed problem. The Air Force canceled the KB-47 program on July 11, 1957.