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

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In designing the U-2 aircraft, Kelly Johnson was confronted with
two major problems-fuel capacity and weight. To achieve interconti­
nental range, the aircraft had to carry a large supply of fuel, yet, it
also had to be light enough to attain the ultrahigh altitudes needed to
be safe from interception. Although the final product resembled a typ­
ical jet aircraft, its construction was unlike any other US military air­
craft. One unusual design feature was the tail assembly, which-to
save weight-was attached to the main body with just three tension
bolts. This feature had been adapted from sailplane designs.
The wings were also unique. Unlike conventional aircraft, whose
main wing spar passes through the fuselage to give the wings continu­
ity and strength, the U-2 had two separate wing panels, which were
attached to the fuselage sides with tension bolts (again, just as in sail­
planes). Because the wing spar did not pass through the fuselage,
Johnson was able to locate the camera behind the pilot and ahead of
the engine, thereby improving the aircraft's center of gravity and re­
ducing its weight.
The wings were the most challenging design feature of the entire
airp~ane. Their combination of high-aspect ratio and low-_drag ratio
(in other words, the wings were long, narrow, and thin) made them
unique in jet aircraft design. The wings were actually integral fuel
tanks that carried almost all of the U-2's fuel supply.
The fragility of the wings and tail section, which were only
bolted to the fuselage, forced Kelly Johnson to look for a way to pro­
tect the aircraft from gusts of wind at altitudes below 35,000 feet,
which otherwise might cause the aircraft to disintegrate. Johnson
again borrowed from sailplane designs to devise a "gust control"
mechanism that set the ailerons and horizontal stabilizers into a posi­
tion that kept the aircraft in a slightly nose-up attitude, thereby
avoiding sudden stresses caused by wind gusts. Nevertheless, the U-2
remained a very fragile aircraft that required great skill and concen­
tration from its pilots.
The final major design feature was the lightweight, bicycle-type
landing gear. The entire structure-a single oleostrut with two light­
weight wheels toward the front of the aircraft and two small,
solid-mount wheels under the tail-weighed only 208 pounds yet
could withstand the force of touchdown for this 7-ton aircraft. Because
both sets of wheels were located underneath the fuselage, the U-2 was
also equipped with detachable pogos (long, curved sticks with two
small wheels on them) on each wing to keep the wings level during
takeoff. The pilot would drop the pogos immediately after takeoff so
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Chapter 2
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