Lockheed U-2 U-2C

The original J57 left the U-2 with very little thrust margin at its operating ceiling, and the answer was to re-engine the airframes with the appreciably more powerful J75-P-13. The change went beyond the engine itself: it demanded a visible widening of the fuselage intakes, the feature that tells a U-2C from a U-2A at a glance. Thirteen aircraft went through the modification. When Lockheed redesigned the aeroplane outright in the mid-1960s, the U-2R kept exactly the J75-P-13B introduced on the U-2C.

The aircraft preserved at the National Air and Space Museum, Article 347 (serial 56-6680), sums up the version on its own: the seventh U-2 built, it was delivered on 9 February 1956 and first used operationally on 4 July that year. It flew initially as a U-2A and was later upgraded to U-2C with the J75-P-13B and the enlarged intakes; at one point it was temporarily fitted with an in-flight refuelling probe and redesignated U-2F. In CIA service it remained unpainted apart from its three-digit production number. The museum acquired it from the U.S. Air Force on 30 August 1982.

U-2Cs also served well away from military reconnaissance. NASA’s High Altitude Missions Branch operated the type on high-altitude research — stratospheric sampling, natural disaster assessment, water and land use studies — and it was alongside that fleet that the ER-2s derived from the TR-1A later flew.