(^86) UNITED STATES
Lockheed SR-71A Blackbird
Max speed: Mach 3.3 (2,200+mph)
at 80,000ft (24,000m)
Powerplant: 2 x Pratt & Whitney J58-1
afterburning turbojets
Power: 34,000lb each
Wingspan: 55ft 7in (16.94m)
Length: 107ft 5in (32.74m)
Height: 18ft 6in (5.64m)
Max T/O weight: 172,000lb (78,000kg)
Ceiling: 85,000ft (25,900m)
Range: 2,900 miles (5,400km)
Payload: 3,500lb (1,600kg)
O
ver 50 years ago a menacing black
shape tore the skies asunder
travelling at over three times the
speed of sound. It was a machine so far
ahead of its time, that even its own pilots
thought it looked more like a spaceship than
an aircraft. It represented such a quantum
leap in performance that no known aircraft
since has come close to challenging its
dominance. Quite simply, the Lockheed
SR-71 Blackbird is the world’s ultimate
speedster, and remains so some two decades
after its retirement.
During the height of the Cold War, Lockheed
was tasked with building an innovative aircraft
to improve intelligence-gathering, one that
would y faster than any aircraft before, at
greater altitude, and with a minimal radar
cross section. President Eisenhower deeply
valued the strategic bene ts of the high- ying
but vulnerable U-2’s airborne reconnaissance
during these tense Cold War times. And now
the call came from Washington to build the
impossible – ‘an aircraft that can’t be shot down- and do it fast’.
Kelly Johnson, one of the pre-eminent aircraft
designers of the 20th century, and his ‘Skunk
Works’ team had a track record of delivering
‘impossible’ technologies on strategically
Lockheed SR-71 Blackbird
critical deadlines. But this new aircraft was in
a di erent category from anything that had
come before. ‘Everything had to be invented,
everything’, Johnson recalled. The speed of the
new aircraft was to exceed 2,000mph. Other
aircraft of the era could, in theory, approximate
that speed but only in short, afterburner-driven
bursts. This new machine needed to maintain
a record-setting speed for hours at a time. At
such velocity, friction with the atmosphere
generates temperatures that would melt the
conventional airframe. Thus, titanium alloy
was the only option for the airframe. Titanium,
however, proved to be a particularly sensitive
material from which to build an aircraft. The
brittle alloy shattered if mishandled. Also, as
a large amount of titanium was required, the
CIA created fake companies around the world
to buy metal from the USSR, which was the
biggest supplier. The aircraft was also painted
black to dissipate heat across the entire
airframe (black paint both emits and absorbs
heat), earning the aircraft its name, ‘Blackbird’.
To reduce the likelihood that the aircraft would
be perceived and shot down, surfaces were
designed to avoid re ecting radar signals, the
engines moved to a subtler mid-wing position,
and a radar-absorbing element was added to
the paint.Two Pratt & Whitney J58 axial- ow turbojets
with afterburners, each producing 32,500lb of
thrust, powered the Blackbirds. Less than 20
per cent of the total thrust used to y at
Mach 3 was produced by the engine itself,
however. During high-speed cruise conditions
the balance of total thrust was produced by
the unique design of the engine inlet and a
moveable conical spike at the front of each
engine nacelle. Under these conditions, air
entering the inlets bypassed the engines, going
directly to the afterburners and ejector nozzles,
thus acting as ramjets.
The original Blackbird was designated the
A-12 and made its rst ight on 30 April 1962.
The single-seat A-12 soon evolved into the
larger SR-71, which added a second seat for a
Reconnaissance Systems O cer and carried
more fuel than the A-12. The SR-71’s rst ight
was on 22 December 1964.
A total of 32 SR-71s were built and the
rst was delivered to the 4,200th (later, 9th)The need for speed
The records set are many. The Blackbird was and remains the world’s fastest and highest- ying
manned aircraft capable of sustained supersonic speed.
On 28 July 1976, SR-71 serial number 61-7962, piloted by then Capt Robert Helt, broke the
world record: an ‘absolute altitude record’ of 85,069ft (25,929m). Several aircraft have exceeded
this altitude in zoom climbs, but not in sustained ight. That same day SR-71 serial number
61-7958 set an absolute speed record of 2,193.2mph (3,529.6km/h), approximately Mach 3.3.
However, SR-71 pilot Brian Shul states in his book ‘The Untouchables’ that he ew in excess of
Mach 3.5 on 15 April 1986 over Libya to evade a missile. The SR-71 also holds the ‘Speed Over a
Recognised Course’ record for ying from New York to London (3,461.53 miles/5,570.79km), at
1,806.964mph (2,908.027km/h), and an elapsed time of 1hr 54min 56.4sec, set on 1 September
1974 while own by James V. Sullivan and Noel F. Widdi eld. This equates to an average
velocity of about Mach 2.72, including deceleration for in- ight refuelling. For comparison, the
best commercial Concorde ight time was 2hrs 52min.Right: Looking as futuristic today as it did then,
it is di cult to believe that the SR-71 was a child
of the sixties. The slender, aerodynamic fuselage
contains most of the SR-71’s fuel, together with
its sensor payload. The ‘Blackbird’ name was
never o cially bestowed on the SR-71. In any
case, most crew members refer to it as the ‘Habu’,
or ‘Sled’.