SR-71 Blackbird Totally Explained

Everything about Sr-71 Blackbird totally explained

The Lockheed SR-71 is an advanced, long-range, Mach 3 strategic reconnaissance aircraft developed from the Lockheed A-12 and YF-12A aircraft by the Lockheed Skunk Works. The SR-71 was unofficially named the Blackbird, and called the Habu by its crews. Clarence "Kelly" Johnson was responsible for many of the design's advanced concepts. A defensive feature of the aircraft was its high speed and operating altitude, whereby, if a surface-to-air missile launch were detected, standard evasive action was simply to accelerate. The SR-71 line was in service from 1964 to 1998, with 12 of the 32 aircraft being destroyed in accidents, though none were lost to enemy action.

Development

Predecessors

The A-12 OXCART, designed for the CIA by Kelly Johnson at the Lockheed Skunk Works, was the precursor of the SR-71. Lockheed used the name "Archangel" for this design, but many documents use Johnson's preferred name for the aircraft, "the Article". As the design evolved, the internal Lockheed designation progressed from A-1 to A-12 as configuration changes occurred, such as substantial design changes to reduce the radar cross-section.
   The first flight, by an A-12 known as "Article 121", took place at Groom Lake, Nevada, on April 25, 1962 equipped with the less powerful Pratt & Whitney J75 engines due to protracted development of the intended Pratt & Whitney J58. The J58s were retrofitted as they became available, and became the standard power plant for all subsequent aircraft in the series (A-12, YF-12, M-21) as well as the follow-on SR-71 aircraft.
   Eighteen A-12 family aircraft were built. One was a pilot trainer with a raised second cockpit for an Instructor-Pilot and 12 were reconnaissance A-12s to be flown operationally by CIA pilots. Three were YF-12As, prototypes of the planned F-12B interceptor version, and two were the M-21 variant. The Air Force reconnaissance version, originally called the R-12, was slightly larger.
   During the 1964 presidential campaign, Senator Barry Goldwater continually criticized President Lyndon B. Johnson and his administration for falling behind the Soviet Union in the research and development of new weapons systems. Johnson decided to counter this criticism by releasing information on the hitherto highly classified A-12 program, and later the existence of the reconnaissance version.

Name and designation

The SR-71 designator is a continuation of the pre-1962 bomber series, which ended with the XB-70 Valkyrie. During the later period of its testing, the B-70 was proposed for the reconnaissance/strike role, with an RS-70 designation. When it was clear that the Lockheed A-12 performance potential was much greater, USAF decided to pursue an RS-71 version of the A-12 rather than the RS-70. However, then-USAF Chief of Staff Curtis LeMay preferred the SR (Strategic Reconnaissance) designation and wanted the RS-71 to be named SR-71. Before the Blackbird was to be announced by President Johnson on 29 February 1964, LeMay lobbied to modify Johnson's speech to read SR-71 instead of RS-71. The media transcript given to the press at the time still had the earlier RS-71 designation in places, creating the myth that the president had misread the aircraft's designation.
This public disclosure of the program and its renaming came as a shock to everyone at the Skunk Works and to Air Force personnel involved in the program. All of the printed maintenance manuals, flight crew handbooks (the source of Paul Crickmoore's page), training slides and materials were labelled "R-12"; while the 18 June 1965 Certificates of Completion issued by the Skunkworks to the first Air Force Flight Crews and their Wing Commander were labelled "R-12 Flight Crew Systems Indoctrination, Course VIII". Following Johnson's speech the name change was taken as an order from the Commander-in-Chief, and immediate reprinting began of new materials, including 29,000 blueprints, to be retitled "SR-71".

Operational history

Although the predecessor A-12 first flew in 1962, the first flight of an SR-71 took place on 22 December 1964, at Air Force Plant 42 in Palmdale, California. The first SR-71 to enter service was delivered to the 4200th (later, 9th) Strategic Reconnaissance Wing at Beale Air Force Base, California, in January 1966. The United States Air Force Strategic Air Command had SR-71 Blackbirds in service from 1966 through 1991.
   SR-71s first arrived at the 9th SRW's Operating Location (OL-8) at Kadena Airbase, Okinawa on 8 March, 1968. These deployments were code named "Glowing Heat," while the program as a whole was code named "Senior Crown". Reconnaissance missions over North Vietnam were code named "Giant Scale".
   On 21 March 1968, Major (later General) Jerome F. O'Malley and Major Edward D. Payne flew the first operational SR-71 sortie in SR-71 serial number 61-7976 from Kadena AB, Okinawa. During its career, this aircraft (976) accumulated 2,981 flying hours and flew 942 total sorties (more than any other SR-71), including 257 operational missions, from Beale AFB; Palmdale, California; Kadena Air Base, Okinawa, Japan; and RAF Mildenhall, England. The aircraft was flown to the National Museum of the United States Air Force near Dayton, Ohio in March 1990. From the beginning of the Blackbird's reconnaissance missions over enemy territory (North Vietnam, Laos, etc.) in 1968, the SR-71s averaged approximately one sortie a week for nearly two years. By 1970, the SR-71s were averaging two sorties per week, and by 1972, they were flying nearly one sortie every day.
   While deployed in Okinawa, the SR-71s and their aircrew members gained the nickname Habu (as did the A-12s preceding them) after a pit viper indigenous to Japan, which the Okinawans thought the plane resembled.
   Operational highlights included:

3,551 Mission Sorties Flown
17,300 Total Sorties Flown
11,008 Mission Flight Hours
53,490 Total Flight Hours
2,752 hours Mach 3 Time (Missions)
11,675 hours Mach 3 Time (Total)

Only one crew member, Jim Zwayer, a Lockheed flight-test reconnaissance and navigation systems specialist, was killed in a flight accident. The rest of the crew members ejected safely or evacuated their aircraft on the ground.
The highly-specialized and advanced tooling used in manufacturing the SR-71 was ordered to be destroyed in 1968 by then-Secretary of Defense Robert McNamara, allegedly because of USAF's and Congress' preference for an F-12B interceptor version over his preferred option of using F-111s as interceptors. Destroying the tooling killed any chance of there being an F-12B, but also limited the SR-71 force to the 32 completed, the final SR-71 order having to be cancelled when the tooling was destroyed.

First retirement

In the 1970s, the SR-71 was placed under closer congressional scrutiny and, with budget concerns, the program was soon under attack. Both Congress and the USAF sought to focus on newer projects like the B-1 Lancer and upgrades to the B-52 Stratofortress, whose replacement was being developed. While the development and construction of reconnaissance satellites was costly, their upkeep was less than that of the nine SR-71s then in service. The SR-71 had never gathered significant supporters within the Air Force, making it an easy target for cost-conscious politicians. Also, parts were no longer being manufactured for the aircraft, so other airframes had to be cannibalized in order to keep the fleet airworthy. The Air Force saw the SR-71 as a bargaining chip which could be sacrificed to ensure the survival of other priorities. A general misunderstanding of the nature of aerial reconnaissance and a lack of knowledge about the SR-71 in particular (due to its early secretive development and usage) was used by its detractors to discredit the aircraft. In 1988, Congress was convinced to allocate $160,000 to keep six SR-71s (along with a trainer model) in flyable storage that would allow the fleet to become airborne within 60 days. The USAF refused to spend the money. The decision to release the SR-71 from active duty came in 1989. Funds were redirected to the financially- troubled B-1 Lancer and B-2 Spirit programs. Four months after the plane's retirement, General Norman Schwarzkopf, Jr. was told that the expedited reconnaissance which the SR-71 could have provided was unavailable during Operation Desert Storm. However, it was noted by SR-71 supporters that the SR-71B trainer was just coming out of overhaul and that one SR-71 could have been made available in a few weeks, and a second one within two months. Since the plane was recently retired, all the support infrastructure was still in place and qualified crews were available. The decision was made by Washington not to bring the aircraft back.

Reactivation

Due to increasing unease about political conditions in the Middle East and North Korea, the U.S. Congress re-examined the SR-71 beginning in 1993.}}
Rear Admiral Thomas F. Hall addressed the question of why the SR-71 was retired, saying it was under "the belief that, given the time delay associated with mounting a mission, conducting a reconnaissance, retrieving the data, processing it, and getting it out to a field commander, that you'd a problem in timeliness that wasn't going to meet the tactical requirements on the modern battlefield. And the determination was that if one could take advantage of technology and develop a system that could get that data back real time… that would be able to meet the unique requirements of the tactical commander." Hall stated that "the Advanced Airborne Reconnaissance System, which was going to be an unmanned UAV” would meet the requirements but wasn't affordable at the time. He said that they were “looking at alternative means of doing [thejob of the SR-71]."
Congress' disappointment with the lack of a suitable replacement for the Blackbird was cited concerning whether to continue funding imaging sensors on the U-2. Congressional conferees stated the "experience with the SR-71 serves as a reminder of the pitfalls of failing to keep existing systems up-to-date and capable in the hope of acquiring other capabilities."
Colonel Jay Murphy (USAF Retired) was made the Program Manager for Lockheed’s reactivation plans. Retired Air Force Colonels Don Emmons and Barry MacKean were put under government contract to remake the plane’s logistic and support structure. Still-active Air Force pilots and Reconnaissance Systems Officers (RSOs) who had worked with the aircraft were asked to volunteer to fly the reactivated planes. The aircraft was under the command and control of the 9th Reconnaissance Wing at Beale Air Force Base and flew out of a renovated hangar at Edwards Air Force Base. Modifications were made to provide a data-link with "near real-time" transmission of the Advanced Synthetic Aperture Radar's imagery to sites on the ground. All other Blackbirds have been moved to museums except for the two SR-71s and a few D-21 drones retained by the NASA Dryden Research Center.

24 December 1957: First J58 engine run.

1 May 1960: Francis Gary Powers is shot down in a Lockheed U-2 over the Soviet Union.

13 June 1962: SR-71 mock-up reviewed by Air Force.

30 July 1962: J58 completes pre-flight testing.

28 December 1962: Lockheed signs contract to build six SR-71 aircraft.

25 July 1964: President Johnson makes public announcement of SR-71.

29 October 1964: SR-71 prototype (#61-7950) delivered to Palmdale.

7 December 1964: Beale AFB, CA announced as base for SR-71.

22 December 1964: First flight of the SR-71 with Lockheed test pilot Bob Gilliland at AF Plant #42.

21 July 1967: Jim Watkins and Dave Dempster fly first international sortie in SR-71A #61-7972 when the Astro-Inertial Navigation System (ANS ) fails on a training mission and they accidentally fly into Mexican airspace.

3 November 1967: A-12 and SR-71 conduct a reconnaissance fly-off. Results were questionable.

5 February 1968: Lockheed ordered to destroy A-12, YF-12, and SR-71 tooling.

8 March 1968: First SR-71A (#61-7978) arrives at Kadena AB to replace A-12s.

21 March 1968: First SR-71 (#61-7976) operational mission flown from Kadena AB over Vietnam.

29 May 1968: CMSGT Bill Gornik begins the tie-cutting tradition of Habu crews neck-ties.

3 December 1975: First flight of SR-71A #61-7959 in "Big Tail" configuration.

20 April 1976: TDY operations started at RAF Mildenhall in SR-71A #17972.

27 July 1976 - July 28, 1976: SR-71A sets speed and altitude records (Altitude in Horizontal Flight: 85,068.997 ft. and Speed Over a Straight Course: 2,193.167 mph).

August 1980: Honeywell starts conversion of AFICS to DAFICS.

15 January 1982: SR-71B #61-7956 flies its 1,000th sortie.

21 April 1989: #974 was lost due to an engine explosion after taking off from Kadena AB. This was the last Blackbird to be lost, it was the first SR-71 accident in 18 years, and it's also the longest accident-free streak of any USAF aircraft ever.

22 November 1989: Air Force SR-71 program officially terminated.

21 January 1990: Last SR-71 (#61-7962) left Kadena AB.

26 January 1990: SR-71 is decommissioned at Beale AFB, CA.

6 March 1990: Last SR-71 flight under SENIOR CROWN program, setting four world records.

25 July 1991: SR-71B #61-7956/NASA #831 officially delivered to NASA Dryden.

October 1991: Marta Bohn-Mayer becomes first female SR-71 crew-member.

28 September 1994: Congress votes to allocate $100 million for reactivation of three SR-71s.

26 April 1995: First reactivated SR-71A (#61-7971) makes its first flight after restoration by Lockheed.

28 June 1995: First reactivated SR-71 returns to Air Force as Detachment 2.

28 August 1995: Second reactivated SR-71A (#61-7967) makes first flight after restoration.

19 October 1997: The last flight of SR-71B #61-7956 at Edwards AFB Open House.

9 October 1999: The last flight of the SR-71 (#61-7980/NASA 844).

September 2002: Final resting places of #956, #971, and #980 are made known.

15 December 2003: SR-71 #972 goes on display at the Steven F. Udvar-Hazy Center in Chantilly, Virginia.

Records

The SR-71 remained the world's fastest and highest-flying operational manned aircraft throughout its career. From an altitude of 80,000 ft (24 km), it could survey 100,000 square miles per hour (72 square kilometers per second) of the Earth's surface. In addition, it was accurate enough to take a picture of a car's license plate from this altitude. On 28 July 1976, an SR-71 broke the world record for its class: an absolute speed record of 1905.80993 knots (2,193.1669 mph, 3,529.56 km/h), and an "absolute altitude record" of 85,068.997 feet (25,929 m). Several airplanes exceeded this altitude in zoom climbs but not in sustained flight.
When the SR-71 was retired in 1990, one was flown from its birthplace at United States Air Force Plant 42 in Palmdale, California to go on exhibit at what is now the Smithsonian Institution's Steven F. Udvar-Hazy Center (an annex of the National Air & Space Museum) in Chantilly, Virginia. The Blackbird, piloted by Colonel Ed Yielding and Lt. Col. J.T. Vida, set a coast-to-coast speed record at an average 2,124 mph (3,418 km/h). The entire trip was reported as 68 minutes and 17 seconds. Three additional records were set within segments of the flight, including a new absolute top speed of 2,242 mph measured between the radar gates set up in St. Louis and Cincinnati. These were accepted by the National Aeronautic Association (NAA), the recognized body for aviation records in the United States. An enthusiast site devoted to the Blackbird lists a record time of 64 minutes. The SR-71 also holds the record for flying from New York to London in 1 hour 54 minutes and 56.4 seconds, set on 1 September 1974. This equates to an average velocity of about Mach 2.68, including slowing down for in-flight refueling. Peak speeds during this flight were probably closer to the declassified top speed of Mach 3.2+. (For comparison, the best commercial Concorde flight time was 2 hours 52 minutes, and the Boeing 747 averages 6 hours 15 minutes.)

Design and operational details

A particularly difficult issue with flight at over Mach 3 is the high temperatures generated. As an aircraft moves through the air, the air in front of the aircraft compresses and this heats the air, and the heat conducts into the aircraft's airframe. To help with this, high temperature materials were needed and the airframe was substantially made of titanium, obtained from the USSR, at the height of the Cold War. Lockheed used all possible guises to prevent the Soviet government from knowing for what the titanium was to be used. In order to control costs, they used a more easily-worked alloy of titanium which softened at a lower temperature. Finished aircraft were painted a dark blue (almost black) to increase the emission of internal heat (since fuel was used as a heat sink for avionics cooling) and to act as camouflage against the sky.
The aircraft was designed to minimize its radar cross-section, an early attempt at stealth design. However, the radar signature minimization didn't take into account the extremely hot particles in the exhaust which reflect radar extremely well. Ironically, the SR-71 was one of the largest targets on the FAA (Federal Aviation Administration) long range radars, which were able to track the plane at several hundred miles.

Air inlets

The air inlets were a critical design feature to allow cruising speeds of over Mach 3.2, yet provide subsonic Mach 0.5 airflow into the turbojet engines. At the front of each inlet was a sharp, pointed movable cone called a "spike" that was locked in the full forward position on the ground or when in subsonic flight. During acceleration to high-speed cruise, the spike would unlock at Mach 1.6 and then begin a mechanical (internal jackscrew powered) travel to the rear. It moved up to a maximum of 26 inches (66 cm).
   The original air inlet computer was an analog design which, based on pitot-static, pitch, roll, yaw, and angle-of-attack inputs, would determine how much movement was required. By moving, the spike tip would withdraw the shock wave, riding on it closer to the inlet cowling until it just touched slightly inside the cowling lip. In this position shock-wave spillage causing turbulence over the outer nacelle and wing was minimized while the spike shock-wave then repeatedly reflected between the spike centerbody and the inlet inner cowl sides. In doing so, shock pressures were maintained while slowing the air until a Mach 1 shock wave formed in front of the engine compressor.
   The backside of this "normal" shock wave was subsonic air for ingestion into the engine compressor. This capture of the Mach 1 shock wave within the inlet was called "Starting the Inlet". Tremendous pressures would be built up inside the inlet and in front of the compressor face. Bleed tubes and bypass doors were designed into the inlet and engine nacelles to handle some of this pressure and to position the final shock to allow the inlet to remain "started." So significant was this inlet pressure build-up (pushing against the inlet structure) that, at Mach 3.2 cruise, it was estimated that 58% of the available thrust was being provided by the inlet, 17% by the compressor and the remaining 25% by the afterburner. Ben Rich, the Lockheed Skunkworks designer of the inlets, often referred to the engine compressors as "pumps to keep the inlets alive" and sized the inlets for Mach 3.2 cruise (where the aircraft was at its most efficient design point). The additional "thrust" refers to the reduction of engine energy required to compress the airflow. One unique characteristic of the SR-71 is that the faster it went, the more fuel-efficient it was in terms of pounds burned per nautical mile traveled. An incident related by Brian Shul, author of Sled Driver: Flying the World's Fastest Jet, was that on one reconnaissance run he was fired upon several times. In accordance with procedure they accelerated and maintained the higher than normal velocity for some time; afterwards they discovered that this had reduced their fuel consumption.
   In the early years of the Blackbird programs the analog air inlet computers wouldn't always keep up with rapidly-changing flight environmental inputs. If internal pressures became too great and the spike was incorrectly positioned the shock wave would suddenly blow out the front of the inlet, called an "Inlet Unstart." The flow of air through the engine compressor would immediately stop, thrust would drop, and exhaust gas temperatures would begin to rise. Due to the tremendous thrust of the remaining engine pushing the aircraft asymmetrically an unstart would cause the aircraft to yaw violently to one side. SAS, autopilot, and manual control inputs would fight the yawing, but often the extreme off-angle would reduce airflow in the opposite engine and cause it to begin "sympathetic stalls." The result would be rapid counter-yawing, often loud "banging" noises and a rough ride. The crews' pressure-suit helmets would sometimes bang on the cockpit canopies until the initial unstart motions subsided.
   One of the standard counters to an inlet unstart was for the pilot to reach out and unstart both inlets; this drove both spikes out, stopped the yawing conditions and allowed the pilot to restart each inlet. Once restarted, with normal engine combustion, the plane could accelerate and climb to the planned cruise altitude.
   The analog air inlet computer was later replaced by a digital one. Lockheed engineers developed control software for the engine inlets that would recapture the lost shock wave and re-light the engine before the pilot was even aware an unstart had occurred. The SR-71 machinists were responsible for the hundreds of precision adjustments of the forward air by-pass doors within the inlets. This helped control the shock wave, prevent unstarts, and increase performance.

Fuselage

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 warmed up 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 extreme temperatures, the aircraft would leak JP-7 jet fuel onto the runway before it took off. 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, too hot to approach. Non-fibrous asbestos with high heat tolerance was used in high-temperature areas. The SR-71 made its debut years before Pyotr Ya. Ufimtsev's ground-breaking research made possible today's stealth technologies, and, despite Lockheed's best efforts, the SR-71 was still easy to track by radar and had a huge infrared signature when cruising at Mach 3.2 or more. It was visible on air traffic control radar for hundreds of miles, even when not using its transponder. SR-71s were evidently detected by radar, as missiles were often fired at them. The flight characteristics of the SR-71 made it almost invulnerable during its service life; not one was shot down, despite over 4,000 attempts to do so.

Chines

One of the Blackbird's interesting and unique features was its chines, sharp edges leading back to the left and right of the nose and along the sides of the fuselage.
   The Blackbird was originally not going to have chines. At its "A-11" design stage, it looked similar to an enlarged F-104. Lockheed's aerodynamicists were concerned that these large surfaces would hurt the aircraft's aerodynamic performance. But the government agencies paying for the project wanted drastically reduced radar cross-section, and pushed Lockheed's aerodynamicists to try chines on a few wind-tunnel models near the end of the configuration design process.
   The aerodynamicists discovered that the chines generated powerful vortices around themselves, generating much additional lift near the front of the aircraft, leading to surprising improvements in aerodynamic performance. The angle of incidence of the delta wings could then be reduced, allowing for greater stability and less high-speed drag, and more weight (fuel) could be carried, allowing for greater range. Landing speeds were also reduced, since the chines' vortices created turbulent flow over the wings at high angles of attack, making it harder for the wings to stall. (The Blackbird can, consequently, make high-alpha turns to the point where the Blackbird's unique engine air inlets stop ingesting enough air, which can cause the engines to flame out. Blackbird pilots were thus warned not to pull more than 3 g, so that angles of attack stay low enough for the engines to get enough air). The chines act like the leading edge extensions that increase the agility of modern fighters such as the F-5, F-16, F/A-18, MiG-29 and Su-27. The addition of chines also allowed designers to drop the planned canard foreplanes. (Many early design models of what became the Blackbird featured canards).
   When the Blackbird was being designed, no other airplane had featured chines, so Lockheed's engineers had to solve problems related to the differences in stability and balance caused by these then-unusual surfaces. Their solutions have since been extensively used. Chines are still an important part of the design of many of the newest stealth UAVs, such as the Dark Star, Bird of Prey, X-45 and X-47, since they allow for tail-less stability as well as for stealth.

Fuel

SR-71 development began using a coal slurry powerplant, Production of the SR-71 totaled 32 aircraft with 29 SR-71As, 2 SR-71Bs, and 1 SR-71C.
Another variant was the SR-71C. It was a hybrid airplane comprised of the rear fuselage of the first YF-12A (S/N 60-6934) and the forward fuselage from a SR-71 static test unit. This Blackbird was seemingly not quite straight and had a yaw at supersonic speeds. It was nicknamed "The Bastard". The YF-12 had been wrecked in a 1966 landing accident.

Flight simulator

The Link Simulator Company's SR-71 Flight Simulator was developed during 1963 – 1965 under a deep "black" security blanket because it and the team Link assigned to it were given access to CIA OXCART and USAF R-12 / SR-71 clearances, the complete list of names of classified vendors supplying parts and software that had to be simulated, the total aircraft performance envelope data and a government-produced satellite photo montage of almost the entire continental United States to provide optical imagery for the RSO's portion of the Flight Simulator. This later capability was mounted on a separate, large, rectangular glass plate (approximately 6 feet by 12 feet in size) over which moved an optical sighting head that traveled at the scaled speed and direction of the Blackbird during its simulated flight. Realistic and accurate images were then displayed in the Optical View Sight and SLR RCD (Radar Correlator Display) in the RSO cockpit. Imagery wasn't provided to the pilot's simulator, which like the RSO simulator, had translucent window panels with varying degrees of lighting to change a simulated flight from daylight to night flying conditions.
   Instructor positions were behind both the pilot's and the RSO's cockpits, with monitoring, malfunction and emergency problem controls provided. The simulator halves could be flown as separate cockpits with different training agendas or in a team mode, where intercom, instrument readings and air vehicle/sub-systems performance were integrated. Although most simulator flights were in a flight suit "shirt sleeve" environment, selected flights during a crew's checkout training were made with the crew wearing the complete David Clark Company's Full Pressure Suit.
   In 1965, when the first Beale AFB Instructor Pilot/RSO crew (wearing civilian clothes only) visited the Flight Simulator during USAF checkout and acceptance trials at Link's upstate New York facilities, they were surprised to park in front of a busy, active grocery store and then be escorted quietly to a side door that led them into a hidden, rear portion of the building that was Link's highly classified "Skunkworks" type facility for the Blackbird program. Total secrecy was so complete that no one in the New York township site was aware of what was going on behind the busy checkout stands selling foodstuffs and beverages.
   In 1965, the Flight Simulator was transferred to Beale AFB, California and the 9th Strategic Reconnaissance Wing's SAGE building, which provided vault level security for it plus the Wing Headquarters, Flight Mission Planning, and Intelligence Analysis / Exploitation of Blackbird mission products.
   Besides SR-71 flight crew training and currency usage, the Flight Simulator was used several times by Lockheed and CIA operatives to analyze Groom Lake A-12 problems and accidents with similar assistance provided for SR-71 flights at Edwards AFB. Another unique feature was that an actual flight mission tape for the SR-71 ANS could be loaded into the Flight Simulator's digital computers, which had been designed and programmed by Link engineers to emulate the Nortronics ANS. During Category II testing at Edwards AFB, some types of ANS navigation errors could be duplicated in the Flight Simulator at Beale AFB, with Link engineers then often assisting in software fixes to the main ANS flight software programs.
   At the conclusion of SR-71 flying at Beale AFB, the Flight Simulator (minus the RSO optical imagery system) was transferred to the NASA Dryden facility at Edwards AFB in support of NASA SR-71 flight operations. Upon completion of all USAF and NASA SR-71 operations at Edwards, the Flight Simulator was moved in July, 2006 to the Frontiers of Flight Museum on Love Field Airport in Dallas, Texas (flightmuseum.com) and, with support from the Museum and Link (now, L-3 Communications Simulation and Training Division), it's intended to be available for viewing by Museum visitors.

Myth and lore

The plane developed a small cult following, given its design, specifications and the aura of secrecy that surrounded it. Specifically, these groups cite that the aircraft's maximum speed is limited by the specific maximum temperature for the compressor inlet of 427 °C (800 °F). Recent studies of inlets of this type have shown that current technology could allow for inlet speeds with a lower bound of Mach 6.
It is known that the J58 engines were most efficient at around Mach 3.2, and this was the Blackbird's typical cruising speed. The SR-71's Pratt & Whitney J58 engines never exceeded test bench values above Mach 3.6 in unclassified tests.
The SR-71 was the first operational aircraft designed around a stealthy shape and materials. The most visible marks of its low radar cross section (RCS) are its inwardly-canted vertical stabilizers and the fuselage chines. Comparably, a plane of the SR-71's size should generate a radar image the size of a flying barn, but its actual return is more like that of a single door. Though with a much smaller RCS than expected for a plane of its size, it was still easily detected, because the exhaust stream would return its own radar signature (even though a special cesium compound was added to the fuel to reduce this signature). Furthermore, this is no comparison to the later F-117, whose RCS is on the order of a small ball bearing.

Succession

Much speculation exists regarding a replacement aircraft for the SR-71, most notably an aircraft identified as the Lockheed Aurora. This is due to limitations on the use of spy satellites which are governed by the laws of orbital mechanics. It may take 24 hours before a satellite is in proper orbit to photograph a particular target: far longer than the time requirements of a reconnaissance plane. Spy planes can provide the most current intelligence information and collect it when lighting conditions are optimum. The fly-over orbit of spy satellites may also be predicted and can allow the enemy to hide assets when they know the satellite is above: a drawback spy planes don't suffer. These factors have led many to doubt that the United States military has abandoned the concept of spy planes to complement reconnaissance satellites.
Another possible reason the SR-71 was retired due to a shift from spy planes to unmanned aerial vehicles (UAVs) and a reliance on reconnaissance satellites.

Specifications (SR-71A)

SR-71 aircraft on display Places to see a Blackbird on display include:

Multiple variants:

National Museum of the United States Air Force at Wright-Patterson Air Force Base, near Dayton, Ohio (an SR-71A, YF-12A and M-21/D-21 drone)
March Field Air Museum, Riverside, California (an SR-71A and a DR-21 Drone)

SR-71A variant:

Air Force Armament Museum, Eglin Air Force Base, Florida
Air Force Flight Test Center Museum, Edwards Air Force Base, California
Air Force Plant 42 Production Flight Test Installation, Palmdale, California
American Air Museum in Britain at the Imperial War Museum, Duxford, Cambridgeshire, England (the only example displayed outside the US)
Barksdale Air Force Base, Bossier City, Louisiana
Beale Air Force Base, Marysville, California
Castle Air Museum, Atwater, California
Evergreen Aviation Museum, McMinnville, Oregon
Kansas Cosmosphere and Space Center in Hutchinson, Kansas
Lackland Air Force Base, San Antonio, Texas
March Field Air Museum, Riverside, California
Museum of Aviation, Warner Robins, Georgia
Pima Air & Space Museum, Tucson, Arizona
Steven F. Udvar-Hazy Center, at Washington Dulles International Airport in Chantilly, Virginia
Strategic Air and Space Museum in Ashland, Nebraska
Virginia Aviation Museum in Richmond, Virginia

SR-71B variant:

Kalamazoo Aviation History Museum, Kalamazoo, Michigan

SR-71C variant:

Hill Air Force Base Museum, Ogden, Utah

Other images

Image:SR71BlackBird1.JPG|SR-71 Blackbird at the Steven F. Udvar-Hazy Center Image:Sr71 at national space museum.jpg|SR-71 Blackbird at the Steven F. Udvar-Hazy Center Image:sr-71.jpg|Blackbird at the Strategic Air and Space Museum in Ashland, Nebraska Image:Pima-SR71.jpg|SR-71 and D-21B at the Pima Air & Space Museum Image:EvergreenSR-71A.jpg|SR-71A (#61-7971) and D-21 drone at the Evergreen Aviation Museum in McMinnville, Oregon

Popular culture

In Manga Science (まんがサイエンス 1 Manga Science

), a science teaching comic short series, volume 2 (2006), an SR-71 was used to demonstrate the heat generated in high speed flight.
In Jeremy Clarkson's nonfiction book I Know You Got Soul, he devotes one chapter to the SR-71.

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