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SR-71 Blackbird
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The Lockheed SR-71 is an advanced,  long range,  Mach 3+ strategic reconnaissance spy aircraft developed by Lockheed Skunk Works as a Black Project. The SR-71 was unofficially named the “Blackbird”.

The call sign of the aircraft, "Blackbird",  signifies the resistance of its airframe to visible light and radar detection. The SR-71 was the first operational aircraft designed around a stealthy shape and materials.

The SR-71 was in service from 1964 to 1998,  none were lost to enemy action.

A defensive feature of the aircraft was its high speed and operating altitude, whereby,  if a surface-to-air missile were detected, standard evasive action was simply to accelerate.

A particularly difficult issue with flight at over Mach 3 is the high temperatures generated. As an aircraft moves through the air at supersonic speed, the air in front of the aircraft is compressed into a supersonic shockwave and the energy generated by this heats the airframe. To address this problem, the SR-71 was made from a substantial amount of the high-temperature material titanium, which was obtained from the USSR at the height of the Cold War. Lockheed used many disguises to prevent the Soviet government from knowing the purpose of the titanium.

The red stripes on SR-71s are to prevent maintenance workers from damaging the skin. The curved skin near the center of the fuselage is thin and delicate. There is no support underneath with exception of the structural ribs, which are spaced several feet apart.

To allow for thermal expansion at the high operational temperatures, the fuselage panels were manufactured to fit only loosely on the ground. Proper alignment was only achieved when the airframe heated due to air resistance at high speeds, causing the airframe to expand several inches. Because of this and the lack of a fuel sealing system that could handle the thermal expansion of the airframe at extreme temperatures, the aircraft would leak JP-7 jet fuel onto the runway before it took off.  (Just imagine any machine that leaked the fueled used to operate it as being normal, especially from a machine as powerful as the SR-71 Blackbird, or even your car).

The aircraft would quickly make a short sprint, meant to warm up the airframe, and was then refueled in the air before departing on its mission. Cooling was carried out by cycling fuel behind the titanium surfaces at the front of the wings (chines). On landing after a mission, the canopy temperature was over 300 °C (572 °F), too hot to approach. Non-fibrous asbestos with high heat tolerance was used in high-temperature areas.

JP-7 is extremely difficult to light in any conventional way, which made the fuel leaking before take off a non fire hazard. When the engines of the aircraft were started, puffs of triethylborane (TEB), which ignites on contact with air, were injected into the engines to produce temperatures high enough to initially ignite the JP-7. The TEB produced a characteristic puff of greenish flame that could often be seen as the engines were ignited. TEB was also used to ignite the afterburners.

SR-71 full pressure flight suit.

Crews flying the SR-71 at 80,000 ft (24,000 m) faced two main survival problems:

1. Human lungs cannot absorb enough 100% oxygen above 43,000 ft (13,000 m) to sustain consciousness and life with a standard pressure demand oxygen mask.

2. The instant heat rise pulse on the body when exposed to a Mach 3.2 air flow during ejection would be about 450 °F (230 °C).

3. Note: If a human being were exposed to the atmospheric pressures found at the Blackbird’s “advertised” operational altitude of 80,000 ft (i.e. no full pressure suit), he or she would be unconscious in 3-5 seconds and dead in less than 10 seconds.

To solve these problems the David Clark Company was hired to produce protective full pressure suits.  Click here to see a photo of the full pressure suit.

After a high altitude bailout, an oxygen supply would keep the suit pressurized. The crew member would then free-fall to 15,000 ft (4,600 m) before the main parachute was opened, allowing the high heat rise to bleed off as the crew member slowed down and descended.

To demonstrate this full pressure suit capability, crew members would wear one of these suits and undergo an altitude chamber explosive decompression to 78,000 ft (24,000 m) or higher while chamber heaters would rapidly turn on to 450 °F (230 °C) and then be turned down at the rate experienced during a real life free-fall.

The cabin could be pressurized to an altitude of 10,000 ft (3,000 m) or 26,000 ft (7,900 m) during flight. Crews flying a low-subsonic flight (such as a ferry mission) would wear either their standard USAF hard hat helmets, pressure demand oxygen masks and nomex flight suit or full pressure suit.

The Pratt & Whitney J58-P engines used on the Blackbird were the only American engines ever designed to operate continuously in afterburner.

The SR-71 was the world's fastest and highest-flying operational manned aircraft throughout its career.

On 28 July 1976, an SR-71 broke the world record for its class: An "absolute altitude record" of 85,069 feet (25,929 m). That same day an SR-71 set an absolute speed record of 1,905.81 knots (2,193.2 mph; 3,529.6 km/h). Several aircraft exceeded this altitude in zoom climbs but not in sustained flight.

The SR-71 also holds the ("Speed Over a Recognized Course") record for flying from New York to London in 1 hour 54 minutes and 56.4 seconds, set on 1 September 1974. For comparison, the best commercial Concorde flight time was 2 hours 52 minutes, and the Boeing 747 averages 6 hours 15 minutes.

More perspective:

The speed of sound or “mach” is about 769 mph. At the SR-71’s “Advertised” speed of mach 3.2+, that’s over 2,463 mph.

So how fast is 2,463 mph? The circumference of the earth at the equator is about 24,901 miles. So the SR-71 can go all the way around the world in a little over 10 hours.

In comparison it will take an AK-47 round about 15 hrs, and a “Tomahawk” cruise missile about 45 hrs.

So what is faster? The average space shuttle can do it in about 1.5 hrs.

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