During my four years in the Air Force, I processed and printed aerial reconnaissance film taken by RF-4C Phantoms. Having that career field, I could have been stationed at Beale AFB and processed film taken by the SR-71 Blackbird. Unfortunately, the Air Force needed me elsewhere so I never got the opportunity to work with the most spectacular aircraft ever built.
The SR-71 Blackbird was a long-range, supersonic reconnaissance aircraft capable of flying at Mach 3.3. Unless there is another top secret aircraft that hasn’t been disclosed to the public, the SR-71 is still the fastest and highest flying production aircraft in the world. The only aircraft that was faster was the X-15 which could fly over 4,000 mph.
Development and History:
The SR-71 serviced the United States for more than 35 years. During that time, it has had a very interesting history. It all began back in the mid 1950s when the United States Air Force and the CIA decided that it would be best to replace the U-2, an aircraft with something that would travel much faster and higher to avoid enemy defenses. Lockheed, the developer of the U-2 was also given the contract to develop this supersonic aircraft after a competition with Convair. The project was called ARCHANGEL and the Skunk Works, a division of the Lockheed Aircraft Corporation went through twelve design proposals before they reached their final design, the A-12.
On January 26, 1960, the CIA ordered twelve A-12 aircraft. The next month, Lockheed began to search for 24 pilots for the A-12. Soon after in May of 1960, Francis Gary Powers was shot down in a U-2 over the Soviet Union. This event resulted in the United States and the Soviet Union signing an agreement not to fly manned vehicles over the Soviet Union again, a treaty that was undermined even before the SR-71 was built.
Research and development continued for a couple years before the first A-12 was completed and taken from Burbank to the Groom Lake test facility on February 26, 1962. A few months later, the A-12 made its first flight on April 25 with Lockheed test pilot Lou Schalk. During this flight, there were a few technical problems with the aircraft so the aircraft did not make its official first flight until April 30, 1962. After this event, a few days later, the aircraft went supersonic for the very first time and reached Mach 1.1 during the second test flight.
The A-12 was primarily an over-flight vehicle that was configured to fly over a target at a very high speed and high altitude. It got all of the coverage that it could and then made it back to the base. Now that the United States signed the treaty with the Soviet Union, the A-12 could never fly over the target that it was designed for. Therefore, the United States Air Force needed something more, the SR-71. The SR-71 was configured to use cameras that were for peripheral coverage. The aircraft did not need to go into enemy airspace. On June 13, 1962, the SR-71 mock-up was reviewed by the Air Force. A month later, the J58, the turbojet engine that was used in the SR-71 and A-12 completed its pre-flight testing.
As all of this was going on, the A-12 still was going through flight-testing. When the A-12 made its first flight, it was with two J75 engines since Pratt & Whitney did not have the powerful J58 completed. On October 5, 1962, with the J58 testing complete, the A-12 flew with a J75 in the left nacelle and the new J58 on the right nacelle. Near the end of that year, Lockheed signed a contract to build six SR-71 aircraft.
Early in 1963, the A-12 made its first flight with two of the J58 engines. During this year, the program experienced its first Blackbird loss when an A-12 crashed near Wendover, Utah on May 24th. Also, the aircraft made its first flight at Mach 3.2, the speed that the aircraft was intended to fly at in November. Due to a political motivation brought on by Barry Goldwater during the upcoming election, President Johnson announced the existence of the Blackbird on February 29, 1964. In June of 1964, the last A-12 was delivered to the Groom Lake test facility. Shortly after, in July, President Johnson made another announcement, this time it was to make public the existence the SR-71. In October, the prototype SR-71 was delivered to Palmdale, CA at Air Force Plant #42. In December, Beale was announced as the base for the SR-71 and on December 22, 1964, the SR-71A prototype made its first flight with test pilot Bob Gilliland at Palmdale.
Two years later on December 28, 1966, the decision was made to terminate A-12 operations by June 1, 1968. The BoB (Bureau of the Budget) decided that it would be too costly to have both the SR-71 and the A-12 programs at the same time because both aircraft are very similar and do similar tasks. In May of 1967, A-12s were flown to Kadena Air Base on Okinawa, Japan and BLACK SHIELD unit was declared operational. Near the end of May of 1967, the first flight of the A-12 in a combat mission over North Vietnam took place, lasting three hours and thirty-nine minutes. In November of 1967, the A-12 and the SR-71 conducted a reconnaissance fly-off to decide which aircraft was superior and worthy to keep. The final choice was the SR-71 but it is still debatable that the A-12 is superior.
In February of 1968, Lockheed was ordered to destroy all tooling used to create the Blackbirds. Also during that year, the first SR-71 arrived at Kadena to replace the A-12s and it also flew its first operational mission on March 21st. May 8th saw the last operational mission of an A-12, which was over North Korea. After this, all A-12s were sent back to Palmdale to be put into storage for several decades before going to museums around the United States.
Speed and Altitude Records:
The SR-71 has accumulated many outstanding achievements. The SR-71 program itself has been a total success based on the fact that the aircraft holds all of the official airspeed and altitude records. On September 13, 1974, an SR-71A set a speed record from London to Los Angeles at an average speed of 1,435.587 mph. On July 28, 1976, an SR-71A set an Altitude in Horizontal Flight record at 85,068.997 feet. On that same day, the aircraft set the Speed Over a Closed Course record of 2,193.167 mph. On July 27, 1976, the SR-71 set a Speed Over a Closed Circuit record at a speed of 2,092.294 mph. On September 1, 1974, the airplane set a record from New York to London in 1 hour, 54 minutes, and 56.4 seconds.
Airframe and Powerplant:
The airframe of the SR-71 is unique. To withstand the friction-generated heat at Mach 3+, over 90 percent of the airframe is made of titanium composite. Also to withstand heat, the main gear tires have been impregnated with aluminum and are filled with nitrogen.
The SR-71 was the first operational aircraft designed around a stealthy shape and materials. There were a number of features in the SR-71 that were designed to reduce its radar signature. The first studies in radar stealth technology seemed to indicate that a shape with flattened, tapering sides would avoid reflecting most radar energy toward the radar beams' place of origin. To this end, the radar engineers suggested adding chines to the design and canting the vertical control surfaces inward. The aircraft also used special radar-absorbing materials which were incorporated into sawtooth shaped sections of the skin of the aircraft, as well as cesium-based fuel additives to reduce the exhaust plumes' visibility on radar. Despite these efforts, the SR-71 was still easily detected on radar while traveling at speed due to its large exhaust stream and air heated by the body (large thermal gradients in the atmosphere are detectable with radar).
Although equipped with defensive electronic countermeasures, the SR-71's greatest protection was its high top speed, which made it almost invulnerable to the attack technologies of the time; over the course of its service life, not one was shot down, despite over 4,000 attempts to do so. All the pilot had to do was to accelerate.
Each J58 engine has 32,500 lbs. of thrust, enough to drive the largest ocean liners. They are the largest of their kind and used to be the most powerful in the world. The engine is one part of a propulsion system, which includes an inlet and an ejector, each producing thrust. In order for the system to work properly over a long period of time, the inlet must capture the onrushing air properly. To do this, a large spike is placed in the inlet and moves forward and back as conditions change. When the air is not captured properly, an event called an unstart occurs. An unstart is best described as a violent yaw where the aircraft pulls to the side where the engine has unstarted. To correct the problem, the pilot must push the spike totally forward and adjust it to capture the air properly; this is called a manual intake. The J58 engines operate as ordinary jets at low speeds, switching to become ramjets at high speeds above 2,000 mph.
SR-71s used JP-7 fuel and there was a special fleet of modified KC-135Q tankers for refueling them. Since the component parts of the Blackbird fit very loosely together to allow for expansion at high temperatures, fuel leaked out constantly while it was at rest on the ground. The fuselage and wing tanks only sealed at operating temperatures. There was little danger of fire from the leaking fuel since JP-7 is very stable with an extremely high flash point.
Preparing for Flight:
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. The suits that the SR-71 crew members wore are identical to those worn by the crews on the space shuttle. After the crew was suited up, they breathed in pure oxygen and filtered 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 was housed. When the crew arrived at the hangar, they shook hands with the buddy crew and then shook hands with each other before entering the aircraft. The pilot and his RSO entered the aircraft and the pilot would tell the ground crew to start the engines. The pilot would then move up the throttle about half way. Triethylborane (TEB), which ignites on contact with air, was injected into the engines to produce temperatures high enough to ignite the JP-7 and a green flash would come out of the ejector. Then there were about 25 minutes of pre-flight checks before takeoff.
When the aircraft completed its pre-flight checks, it would pull out of the barn and move onto the runway. From there, the SR-71 would perform engine run-ups and then the ground crew would pull the chocks. The SR-71 would start to roll down the runway slowly and then accelerate rather rapidly after the afterburner was lit. The feel has been described as a freight train moving down hill. At approximately 230 knots, the airplane lifted off of the runway.
After the SR-71 took off, it had a rendezvous with a KC-135Q tanker seven minutes later. The SR-71 took off with a very light fuel load and after this refueling, the plane could fly up to 2,500 miles without refueling. The aircraft then accelerated to speed and altitude which was about Mach 3.2 at 85,000 feet. The SR-71 then took photos of the targeted area and had another rendezvous with a tanker before returning home. After the flight, the photography equipment was removed and was analyzed immediately. The photography was then sent to the CIA, or whoever needed this valuable intelligence.
Sensors and Payloads:
Original capabilities for the SR-71 included optical/infrared imagery systems, side-looking airborne radar (SLAR), electronic intelligence (ELINT) gathering systems, defensive systems (for countering missile and airborne fighter threats) and recorders for SLAR, ELINT and maintenance data. I remember developing SLAR images taken by RF-4Cs in Germany. We had to run it through a correlater to bring out the true image.
Imagery systems used on the Blackbird were diverse. At the simple end of the spectrum, SR-71s were equipped with a Fairchild tracking camera of modest resolution and an HRB Singer infrared-tracking IR camera, both of which ran during the entire mission to document where the aircraft flew and answer any post-flight political charges of overflight.
One of many types of cameras used was the HYCON Technical Objective Camera (TEOC) that could look straight down or up to 45 degrees left or right of centerline. SR-71s were equipped with two of them, each with a six-inch (152 mm) resolution and the ability to show such details as the painted lines in parking lots from an altitude of 83,000 feet (25,000 m).
Retirement:
In 1989, the Air Force SR-71 program was officially terminated due to budgetary reasons. The argument was that the aircraft could be replaced with spy satellites and maintaining the plane was too costly. This early retirement decision was realized to have been a large mistake and in September of 1994, Congress voted to allocate 100 million dollars for the reactivation of three SR-71s. Then in April of 1995, the first reactivated SR-71A (61-17971) made its maiden flight after being refurbished by Lockheed. In June, the first reactivated aircraft returned to the Air Force inventory. Shortly after, in August, the second aircraft was reactivated (61-17967) and made its first flight after being refurbished by Lockheed. These last SR-71s were permanently retired in 1998. The Air Force quickly disposed of their SR-71s, leaving NASA with two flyable Blackbirds until the last flight in October 1999.
There were 18 A-12s and 32 SR-71s built. Of these, 20 were lost in crashes. The 30 remaining aircraft have been moved to museums except for the two SR-71s and a few D-21 drones retained by the NASA Dryden Flight Research Center.
Facts and General Characteristics of the SR-71:
Contractor: Lockheed Aircraft Corp (Skunk Works)
Type: High-altitude reconnaissance
Crew: Two – Pilot and Reconnaissance Systems Officer (RSO)
Wingspan: 55 ft. 7 in. (16.94 m)
Length: 107 ft. 5 in. (32.74 m)
Height: 18 ft. 6 in. (5.64 m)
Payload: 3,500 lb. (1,600 kg) of sensors
Weight: Empty 67,500 lb. (30,600 kg), Max. Takeoff: 172,000 lb. (78,000 kg)
Power Plant: Two Pratt & Whitney J58-1 continuous-bleed afterburning turbojets
Max thrust: 34,000 lbf (151 kN) each
Max speed: Mach 3.3 (2,200+ mph or 3,530+ km/h)
Rate of Climb: 11,810 ft/min (60 m/s)
Ceiling: 85,000 ft. (25,900 m)
Range: 2,900 miles (5,400 km)
Facts and General Characteristics of the Model:
This model is a replica of aircraft 61-17974 which crashed on April 21, 1989. Both crew members ejected safely.
Manufacturer: Testors
Scale: 1/48
Wingspan: 14"
Length: 26.8"
Height: 5"
Hours to build and paint: 12
