The Central Intelligence Agency and Overhead Reconnaissance; The U-2 and OXCART Programs, 1954-1974

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6ee1 et NOFOAN
Chapter 6
First flight of the A-12,
30 April 1962
Initial testing could not explore the A-12·s maximum potential,
since the J58 engine was stil l not ready. Developing this power plant
to OXCART specifications was proving much more difficult than
had been expected because the J58 had to reach performance levels
never before achieved by a jet engine. while operating under ex­
tremely difficult environmental conditions. To simulate the stress
that the J58 would undergo during maximum power output (Mach
3.2 at 97,000 feet), the power plant was tested in the exhaust stream
of a 175 engine. ln the course of this extremely severe testing, the
J58• s problems were gradually overcome. By January 1963, Pratt &
Whitney had delivered 10 J58 engines to the Nevada testing site.
The first flight of an A- 12 with two J58 engines took place on
15 January 1963. µ
SPEED-RELATED PROBLEMS
As 158-equipped A-12s reached higher and higher speeds. more diffi­
culties arose. Major problems developed at speeds between Mach 2.4
and 2.8 because the aircraft's shock wave interfered with the flow of
air into the engine. greatly reducing its performance. Solving this
problem required long and often highly frustrating experimentation
•· William H. Brown. ··J58/SR-7 I Propulsion lntt!gration." Studies i11 /ntellis:,·11c,e 26
(Summt!r 1981):pp. 17-18 (U): OSA History. chap. 20. pp. 5~. 67 (TS Co<lc:wor<l).