Lockheed U-2 variant
Lockheed U-2 U-2F
An air-refuelling-capable version derived from the J75-powered U-2C, with five airframes converted. Taking fuel from a KC-97 or KC-135 nearly doubled the aircraft’s reach, yet the capability was barely used: pilot fatigue set a limit the design had never accounted for.
- 5
- Units built
History
Range the pilot could not use
In May 1961, seeking to stretch the U-2’s already considerable range, Lockheed fitted six CIA aircraft and several USAF machines with aerial refuelling equipment able to take fuel from either a KC-97 or a KC-135. On paper the gain was dramatic: range rose from roughly 4,000 to 8,000 nautical miles — 7,400 to 15,000 kilometres — and endurance passed fourteen hours. Each modified aircraft also carried an extra oxygen cylinder.
Designations
The conversion produced two parallel designations according to powerplant: J57-powered aircraft became U-2Es, while those already fitted with the J75 were redesignated U-2F. The sole U-2H combined air refuelling with carrier capability.
Little practical use
The modification solved a technical problem and ignored a human one: nobody had considered pilot fatigue in a pressure-suited cockpit for more than half a day aloft, so the refuelling capability was hardly exercised. Its traces survive on individual airframes: the National Air and Space Museum’s Article 347 carried the refuelling probe for a time and flew as a U-2F during that period.