Credit: NASA. Titanium skin. Because the aircraft was designed to fly faster than 2, mph, friction with the surrounding atmosphere would heat up the fuselage to a point that would melt a conventional airframe. The plane was therefore made of titanium, a metal that was able to withstand high temperatures while also being lighter than steel. Using titanium presented other problems, however. First, a whole new set of tools -- also made of titanium -- had to be fabricated, because regular steel ones shattered the brittle titanium on contact.
Second, sourcing the metal itself proved tricky. The US government had to purchase a lot of that, probably using bogus companies," said Merlin.
The initial aircraft were flown completely unpainted, showing a silver titanium skin. They were first painted black in , after the realization that black paint -- which efficiently absorbs and emits heat -- would help lower the temperature of the entire airframe.
The "Blackbird" was born. Same plane, different names. The A was soon evolved into a variant that was designed as an interceptor -- a type of fighter aircraft -- rather than a surveillance plane. Two As were modified to carry a special reconnaissance drone, designated D The modified As were redesignated Ms.
These were designed to take off with the D drone, powered by a Marquart ramjet engine mounted on a pylon between the rudders. The M then hauled the drone aloft and launched it at speeds high enough to ignite the drone's ramjet motor. Lockheed also built three YFAs but this type never went into production. Two of the YFAs crashed during testing. The first SR flew on December 22, These were retired in after only one year of operational missions, mostly over southeast Asia.
After the Air Force began to operate the SR, it acquired the official name Blackbird-- for the special black paint that covered the airplane. This paint was formulated to absorb radar signals, to radiate some of the tremendous airframe heat generated by air friction, and to camouflage the aircraft against the dark sky at high altitudes.
The RSO operated with the wide array of monitoring and defensive systems installed on the airplane. This equipment included a sophisticated Electronic Counter Measures ECM system that could jam most acquisition and targeting radar.
In addition to an array of advanced, high-resolution cameras, the aircraft could also carry equipment designed to record the strength, frequency, and wavelength of signals emitted by communications and sensor devices such as radar. The SR was designed to fly deep into hostile territory, avoiding interception with its tremendous speed and high altitude. It could operate safely at a maximum speed of Mach 3. The crew had to wear pressure suits similar to those worn by astronauts.
These suits were required to protect the crew in the event of sudden cabin pressure loss while at operating altitudes. A typical Blackbird reconnaissance flight might require several aerial refueling operations from an airborne tanker.
Each time the SR refueled, the crew had to descend to the tanker's altitude, usually about 6, m to 9, m 20, to 30, ft , and slow the airplane to subsonic speeds.
As velocity decreased, so did frictional heat. This cooling effect caused the aircraft's skin panels to shrink considerably, and those covering the fuel tanks contracted so much that fuel leaked, forming a distinctive vapor trail as the tanker topped off the Blackbird. As soon as the tanks were filled, the jet's crew disconnected from the tanker, relit the afterburners, and again climbed to high altitude. Cuban missions were flown directly from Beale. The SR did not begin to operate in Europe until , and then only temporarily.
In , when the U. When the SR became operational, orbiting reconnaissance satellites had already replaced manned aircraft to gather intelligence from sites deep within Soviet territory. The aviation pioneer Clarence "Kelly" Johnson headed the project. Though it was successful, fears arose that Soviet technology was catching up and could render the aircraft obsolete. The jet was commissioned by the Central Intelligence Agency. Here's a model of it that sits outside its headquarters in Langley, Virginia.
Compared with its predecessor, the Blackbird had more radar-reflecting surface and was less easily detected by enemy antiaircraft. Two crew members would command the bird, with only pilot in the front and a reconnaissance and navigation officer in the back. The crew would wear spacesuit-like uniforms as they embarked high in the upper altitudes. Here's the one-man cockpit of the high-speed spy plane.
They enabled the high altitude, supersonic flights the Blackbird would undertake. The jet could fly at speeds of over 2, mph, about three times the speed of sound, at altitudes greater than 80, feet.
When in danger, the pilot could simply engage the afterburners and cruise away from any threat — including a missile. The speed and altitude ceiling of the Blackbird meant it could cross continents in just a few hours. Pilots navigating by sight couldn't rely on ground features such as roads, depending instead on mountains and major coastlines. When it ran low on fuel, a tanker would be sent in to give it a top-off, allowing it to stay in the air for long periods.
Blackbirds would often depart with minimum fuel and then be refueled once airborne before heading to a mission zone. Expensive to maintain and fly, the SR was retired from the Air Force in The speeds at which the Blackbird hurtled along resulted in extremely punishing conditions. Anticipating this, designers chose to build the SR almost entirely out of titanium, a metal that is heat resistant and relatively lightweight but difficult to work with.
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