SR-71 Blackbird Spy Plane
Courtesy Boeing Museum of Flight and Wikipedia, the free encyclopedia.
Edited by David Barth November 2014. Photos are by David Barth.
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| Boeing Museum of Flight. |
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| SR-71 Blackbird Spy Plane. |
This is a front section of a Blackbird that visitors can sit in.
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| SR-71 Blackbird Spy Plane. |
This is the rear of the SR-71 showing the D21 drone mounted on top. One drone, launched from international airspace, flew into China
and disappeared. Later, after a drone impacted the cockpit of the SR-71 launch plane, resulting in the remaining D21 drones being
retired and mothballed. The drones used the same J58 turboramjet engine as the Blackbirds.
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SR-71 Blackbird Spy Plane.
This is the front wheelwell. |
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| SR-71 Blackbird Spy Plane. |
This is the front end of a J58 turboramjet engine showing the pointed spike that can move 30 inches to keep the shock wave properly
positioned to enter the engine, depending on the aircraft's speed.
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| SR-71 Blackbird Spy Plane. |
As shown, the Blackbird flies in afterburner all the time except when landing and tanking. The bright spots in the exhaust are called
"shock diamonds." Tanking was from special, dedicated tankers carrying JP7 fuel which could not be used by any other aircraft.
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| A Pratt & Whitney J58 turboramjet. |
| SPECIFICATIONS FOR PRATT & WHITNEY J58 ENGINE |
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| ITEM | SPECIFICATION |
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| Take-off Thrust | 34,000 lbs. (15,300 kg) at sea level |
| Dry Weight | 6,500 lbs. (2,925 kg) |
| Diameter | 4 ft. 2 in. (1.27 m) |
| Length | 15 ft. (4.57 m) |
This engine is on loan from the United Technologies Corporation, Pratt & Whitney Group
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The inlet end of a Pratt & Whitney J58
turboramjet. |
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The exhaust end of a Pratt & Whitney J58
turboramjet showing the afterburner. |
The small holes inject fuel into the rear of the engine to provide additional thrust from afterburning.
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| The design of the Pratt & Whitney J58 engine inlet. |
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Main landing gear of the SR-71 Blackbird with a
McDonnell F4 Phantom in the background. |
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Special BF Goodrich tires were used on the Blackbirds.
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The tires are impregnated with aluminum powder to expel heat and filled with nitrogen because any oxygen inside them would ignite at the
high temperatures generated in high-speed flight.
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| SR-71 Blackbird BF Goodrich tire. |
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| SR-71 Blackbird Spy Plane. |
The J58 Engine Start Cart is called the "Buick" by Blackbird pilots because of its two Buick Wildcat V8 automobile racing engines.
Through a series of gears, the two Buick engines drive a vertical shaft connected to one of the Blackbird's J58 aircraft engines. The
"Buicks" have no mufflers and full throttle is needed to crank the engine to a starting speed of 3,200 rpm. The noise is deafening.
The sound during startup has been described by SR-71 pilots as a "combination shuttle launch and drag race."
Start cart is on loan from the U.S. Air Force Heritage Program.
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| J58 engine Start cart. |
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Blackbird engines were started with the planes
inside their hangars. |
A "Buick" is in the shadow area below the right wing. When the "Buick" had rotated the engine up to 3,200 rpm, tri-ethyl borane (TEB)
was injected into the engine to light it off.
Note that the Blackbird does not have a D21 mounted on top. D21s never got beyond the testing stage, and mission flights did not use
them.
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| SR-71 Blackbird with a D21 drone mounted on top. |
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| SR-71 Blackbird with a D21 drone mounted on top. |
Pratt & Whitney J58 engine record-breaking Speed records made in 1976 by the amazing J58-powered Lockheed Blackbird still stand as of
2014.
In one second at high speed and altitude, two J58 turboramjets consume 2.2 gallons (8.4 l) of fuel and 200,000 cubic feet (6,000 cubic m)
of air.
The thirsty engines are why the planes had to tank after takeoff and at intervals along their planned route. They usually tanked prior
to zooming to 95,000+ feet for the signals and imaging acquision run, and then slowed down and dropped to a lower altitude to tank again.
All tanking was accomplished at subsonic speeds and at altitudes below 40,000 feet.
As the fuselage cooled, it shrank, causing gaps in the fuel tanks that resulted in a fuel spray behind the plane. After tanking, the
Blackbird went to afterburner and climbed back to altitude, heating up as it went, which effectively sealed the fuel tanks.
Tanking was critical. It is not known if a Blackbird ever ran out of fuel, although it is known that there were at least two landings at
unplanned air fields in South Dakota and Denver, Colorado.
The most expensive items for a flight were the cost of flying all of the tankers as well as air force fighters to protect it during ascent
and descent phases of the mission.
As the Blackbird blazes through the sky, its J58 engines grow six inches (15 cm) in length and two and a half inches (6 cm) in diameter
due to the extreme heat.
All of this speed and power made the J58 as unique as the plane they propel. It is the only engine rated for continuous afterburner,
the first to use fuel as hydraulic fluid, and has engine oil that can operate at 550 degrees F without degradation. The Museum's engine
was built in February of 1964 and installed in an A-12, one of the first aircraft in the Blackbird series.
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| SR-71 Blackbird with a D21 drone mounted on top. |