The SR 71:Before and after Take Off

 
A close up of the SR 71 cockpit taken from a KC 135

 The SR 71 refuelling in midflight from a KC 135 tanker

Picture Courtesy: NASA SR 71 image gallery

When the aircraft has completed its pre-flight checks, it will pull out of the barn and move onto the runway. From there, the SR-71 will perform engine run-ups and then the ground crew will pull the chocks. The SR-71 will start to roll down the runway slowly and then accelerate rather rapidly after the afterburner is lit. The feel has been described as a freight train moving down hill. At approximately 230 knots, the airplane lifts off of the runway.
Before any flight, the crew would receive a high protein, low residue meal of steak and eggs. After that, the crew would have a brief medical examination. Following the examination, the crew would get suited up and the Physiological Support Division would check the suit integration.Since the SR 71 operates at a maximum speed of Mach 3.3 at an altitude more than sixteen miles, or 25,908 m (85,000 ft), above the earth,the crew have 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 The suits that the SR-71 crew members wear are identical to those worn by the crews on the space shuttle. After the crew is suited up, they breathe in pure oxygen and filter out any other gas from their body before takeoff. Then the crew would go out to the van for the trip to the barn where the SR-71 is housed. When the crew arrives at the hangar, they shake hands with the buddy crew and then shake hands with each other before entering the aircraft. The pilot and his RSO enter the aircraft and the pilot will tell the ground crew to start the engines. The pilot will then move up the throttle about half way. TEB is shot into the tailpipe of the aircraft and a green flash is seen out of the ejector. Then there are about 25 minutes of pre-flight checks before takeoff.

FUEL
In order for the SR-71 to fly the worldwide missions, it has a special fleet of modified KC-135Q tankers for refueling. SR-71s run on JP-7 fuel, that fills the six large tanks in the fuselage. The component parts of the Blackbird fit very loosely together to allow for expansion at high temperatures. At rest on the ground, fuel leaks out constantly, since the tanks in the fuselage and wings only seal at operating temperatures. There is little danger of fire since the JP-7 fuel is very stable with an extremely high flash point. Originally developed for the A-12 Oxcart plane in the late 1950s, the JP-7 jet fuel had a relatively high flash point (60 °C) to cope with the heat. In fact, the fuel was used as a coolant and hydraulic fluid in the aircraft before being burned. The fuel also contained fluorocarbons to increase its lubricity, an oxidizing agent to enable it to burn in the engines, and even a cesium compound, A-50, which disguised the exhaust's radar signature. As a result, JP-7 was claimed to be more expensive than single malt Scotch whisky.JP-7 is very slippery and extremely difficult to light in any conventional way. The slipperiness was a disadvantage on the ground, since the aircraft leaked fuel when not flying, but at least JP-7 was not a 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.
After the SR-71 takes off, it has a rendezvous with a KC-135Q tanker seven minutes later. The SR-71 takes off with a very light fuel load and after this refueling, the plane can fly up to 2,500 miles without refueling. The aircraft then accelerates to speed and altitude which is about Mach 3.2 at 85,000 feet. The SR-71 then takes photos of the targeted area and has another rendezvous with a tanker before returning home. After the flight, the photography equipment is removed and is analyzed immediately. The photography is then sent to the CIA, or whomever needs this valuable intelligence.