SR-71 Blackbird: the fastest aircraft in the world



In the middle of the 60-s of the last century, residents of American megacities repeatedly appealed to the city administration with complaints of strange phenomena occurring in the sky. In a completely cloudless weather, thunder unexpectedly resounded in the sky and, rapidly dying down, disappeared without a trace.



As time went. Mysterious thunder continued to periodically frighten ordinary Americans. Finally, July 10 1967, after single complaints escalated into mass discontent, the United States Air Force made an official statement in which it was reported that strange thunder occurs as a result of the flights of supersonic strategic intelligence officer Lockheed SR-71.

Continuation of this stories There were several dozen lawsuits of American citizens in which they demanded that the Air Force compensate for the damage caused during the flights. The amount that the military had to pay by the court was 35 thousand dollars, however, in the thirty-year history of the fastest and one of the most expensive military aircraft in operation, the SR-71 is a small drop in a sea of ​​victories and defeats.

The history of creation, or like, as better, but it turned out, as always
SR-71 Blackbird: the fastest aircraft in the world


The first flight of the Blackbird or the Black Bird, as the US military nicknamed the SR-71 for its appearance, took place on December 22 of the year 1964. New supersonic reconnaissance aircraft were intended for use by the US Air Force, which at that time did not have a worthy rival to the supersonic reconnaissance aircraft of the new generation A-12, which was in service with the CIA.

At that time, the A-12 was the fastest aircraft in the world - approximately 3300 km / h and had one of the highest ceilings of maximum height - 28,5 km. Initially, the CIA planned to use А-12 for reconnaissance over the territory of the Soviet Union and Cuba, however, the plans had to be changed in connection with the event that took place on 1 on May 1960, when the predecessor of "Titanium Goose" (as they called А-12) U-2 was shot down Soviet anti-aircraft missile system. The CIA decided not to risk expensive aircraft and used reconnaissance in the USSR and Cuba using satellites, and A-12 sent to Japan and North Vietnam.


A-12


To A-12 Chief Designer Clarence "Kelly" Johnson, such a distribution of reconnaissance forces seemed to be unfair and, beginning in 1958, he began to negotiate closely with the Air Force top command to create a more sophisticated military aircraft that could combine the functions of a reconnaissance and bomber.

Four years later, the US Air Force finally appreciated the possible advantages that they could get if they had an A-12 or its possible prototype in service and gave their consent. By that time, Johnson and his team had been working on two new models, the R-12 and RS-12, for over a year. A few months later, the mockups were ready and Johnson presented them to the "torn apart" air force commander. General Li Mei, who arrived at the presentation, was extremely unhappy. He stated that the RS-12 is nothing more than a repetition of the North American Aviation bomber designed at that time - XB-70 Valkyrie, a modification of the RS-70.

Perhaps the reason for such a statement was: firstly, the combat mission of both aircraft — reconnaissance bombers; secondly, the ability to refuel in the air for both models, and thirdly, the maximum speed, both of them have three times the superior speed. sound. In all other respects, neither in size, nor in form, nor in terms of their technical characteristics are the planes completely alike.



1) Length RS -12 - 32,74 m / Length Valkyrie - 56,6 m.
2) Wingspan RS -12 - 16,94 m / Wingspan Valkyrie - 32 m
3) The maximum speed of the RS-12 (at that time was assumed) - more than 3300 km / h / The maximum speed of the Valkyrie - 3200 km / h.



Convince General Maya Johnson and could not. Moreover, the dispute became so serious that the US Secretary of Defense Robert McNamara had to intervene. Without taking sides, he simply ordered that the development of both aircraft be stopped. If someone else had replaced Johnson, then perhaps the projects would have remained just projects. However, Hall Hibbard, Johnson’s manager and head of the project for the creation of the first F-117 Stealth aircraft, said quite rightly about him: “This damn Swede literally sees the air.” Perhaps now Johnson saw the air better than before and therefore decided to use his last chance.

He simply changed the abbreviation RS decoding from “Reconnaissance Strike” (reconnaissance / shock) to “Reconnaissance Strategic” (strategic intelligence officer). Thus, having changed the combat function of his aircraft, no one could reproach him for duplicating Valkyrie and he continued to develop the RS-12.

In the SR-71, the RS-12 model evolved quite by accident. In his speech in July 1964, the President of the United States (namesake Johnson) Lyndon Johnson, speaking about the RS-12 aircraft, mixed up the letters in some places and said SR-12. Incidentally, this was not the only misstep by the president in his speeches concerning aircraft. In February of the same year, Johnson read, instead of the abbreviation AMI (Advanced Manned Interceptor - a promising manned interceptor), the name A -11, which also later became the official name.



The 71 index, Clarence Johnson, took as an indication that his scout model is the next step after the Valkyrie project. This is how Lockheed SR -71 ("Blackbird") appeared.

In fact, the SR-71 was a prototype of two other aircraft of the Johnson design - A-12 and YF-12, which at the same time combined the functions of an interceptor and a scout. It was YF-12 that became the model from which Johnson eventually began to make a start. Compared to YF-12, it increased the size of the SR-71: its length was 32,7 meters instead of 32 m, and height 5,64 m instead of 5,56. In the entire history of world military and civil aviation, the SR -71 is one of the longest aircraft. It is rare to find a model whose length reaches at least 30 meters. But despite this, thanks to a record speed and one of the largest ceiling heights - 25,9 km, SR-71 joined the ranks of unobtrusive first-generation airplanes - the Stealth.

Johnson increased the maximum take-off mass, instead of 57,6 tons, like the YF-12, SR-71 began to weigh on the take-off 78 tons. The phrase “they wanted the best, but it turned out as always.” It was not easy to lift such a mass into the air, so Johnson decided to use the in-flight refueling system with the help of a specially converted KC-135 Q tanker aircraft. The scout was lifted into the air with a minimal amount of fuel, which made it much easier. Refueling was carried out at an altitude of 7,5 km. Only after that SR -71 could be sent on a mission. Without refueling, he could hold out in the air, as well as the previous 1,5 models of the hour, however, during this time he overcame 5230 km - 1200 km more than A-12 and YF-12. One flight with refueling cost the US Air Force 8 million dollars, which soon forced the military command, following the example of the CIA with A-12, to scream about the cost of flying SR-71.



The fact is that on December 28, the X-NUMX program for the production and development of intelligence officer A-1968 was closed. The company Lockheed Corporation called the main reason for the high cost of operation of the Titanium Goose (data on the cost of one departure A-12 not). Moreover, there was no point in continuing its production, while for service for two years a more sophisticated SR-12 stood. The CIA at that time had already given all of its A-71 air forces and in return received spy satellites with the most modern photo equipment. Looking ahead, we can say that one of the reasons why the surviving SR-12 began to be decommissioned from 71 to 1989 was the high cost of operation. Over the 1998 of the SR-34 model, the USAF spent more than 71 billion dollars flying on 31 flights. Save did not work.

Finally, the most important difference and the unsurpassed advantage so far is the supersonic speed SR -71 - 3529,56 km / h. This figure is three times the speed of sound in the air. A-12 and YF-12 lost to Blackbird over 200 km / h. In this regard, Johnson's aircraft made a revolution. After all, the world's first supersonic aircraft appeared in the 1954 year, just eight years before the A-12 or SR-71. The maximum speed that he could develop, barely exceeded the speed of sound - 1390 km / h. In 1990, thanks to its speed, “Blackbirds” avoided the usual “conservation” in museums and hangars of military bases, since NASA, where several copies were transferred, showed considerable interest in them.



At SR-71, scientists and designers from NASA conducted aerodynamic studies on AST (Advanced Supersonic Technology - promising hypersonic technology) and SCAR (Supersonic Cruise Aircraft Research - development of aircraft with hypersonic flight speeds) programs.


The minimum level of hypersonic speed is about 6000 km / h.

In the sky, everything was not easy

High speed not only solved the tasks set by Johnson, but also created many difficulties in the operation of the “Blackbird”. At the Mach 3 speed (Mach number = 1 the speed of sound, i.e. 1390 km / h), the air friction was so great that the aircraft’s titanium skin was heated to 300 ºС. However, Johnson solved this problem. Minimal cooling was provided by the black paint of the hull, made on a ferrite basis (ferrite - iron or iron alloy). It performed a dual function: firstly, it dissipated heat entering the surface of the aircraft, secondly, it reduced the radar visibility of the aircraft. In order to reduce the visibility of ferrite paint is very often used in military aviation.


Engine "Blackbird" - Pratt & Whitney J58-P4. Length - 5,7 m. Mass - 3,2 tons


The main "conditioner" in the design of the SR-71 was the special fuel JP-7, which was developed for US supersonic aircraft. Thanks to its constant circulation from the fuel tanks, through the skin of the aircraft, the Black Thrush hull was constantly cooled to the engines, and the fuel managed to warm up to 320 ºС during this time. True, the technical advantages of JP-7 were not justified by its consumption. At cruising speed, two Pratt & Whitney J58 scout engines consumed about 600 kg / min.

At first, the circulation system was a major headache for engineers. JP-7 fuel could easily leak even through the smallest leaks. And there were more than enough of these in the hydraulic and fuel systems. By the summer of 1965, the problem of fuel leakage was finally solved, but the chain of failures of the Blackbird was just beginning.

25 January 1966, the first SR -71 crashed. The scout flew at a height of 24 390 m with the speed of Mach 3, at this moment the plane lost control due to the failure of the air intake control system. Pilot Bill Weaver successfully catapulted, despite the fact that the ejection seat remained in the plane. On the SR-71, Johnson installed new ejection seats that allowed pilots to safely leave the cockpit at an altitude of 30 m and Mach 3 speed. Perhaps it was a fluke, it just vomited out of the cabin with a stream of air. Weaver’s partner Jim Sauer also managed to eject, but he could not survive.

An air intake is an element of aircraft design that serves to take in ambient air and then feed it to various internal systems. Air from the air intake can serve as a coolant, oxidizer for fuel, creating a supply of compressed air, etc.


Air intake "Blackbird"


Bill Weaver conducted most of the Blackbird trials. For him it was not the only disaster, as well as for his companions. 10 January 1967 of the year SR-71 held high-speed runs on the runway. For greater complexity, the strip was wet beforehand in order to enhance the effect of sliding. Having landed on the lane at a speed of 370 km / h, the pilot Art Peterson could not release the braking parachute. It is worth noting that the separation speed from the SR-71 band is 400 km / h. Of course, conventional brakes could not stop the scout on a wet surface and the SR-71 continued to move along the runway at the same speed. As soon as he stepped onto the dry section of the track, all the chassis tires burst from the heat. Bare chassis wheels began to strike sparks, causing the wheel hubs made of magnesium alloy to catch fire. If we consider that magnesium alloys ignite at temperatures from 400 to 650ºС, then about the same temperature was in the area of ​​the chassis during braking. The plane stopped only when it slipped through the whole lane and hit its nose into the soil of the dried lake. Peterson survived, however, received numerous burns.

The failure of the braking parachute turned out to be a single case, but the magnesium bushes repeatedly led to the ignition of the Blackbird. In the end, the engineers replaced the magnesium alloy with aluminum.



The last accident in the test program occurred again due to the failure of the air intake. 18 December 1969, the crew of the SR-71 was working on the onboard electronic warfare system. As soon as the scout reached the maximum speed, the pilots heard a strong bang. The plane began to lose control and gave a sharp roll. After 11 seconds after the cotton, the commander of the crew gave the order to eject. The plane crashed, and it was not possible to find out the exact cause of the accident. However, experts have suggested that the disaster occurred due to the failure of the air intake. Sharp roll, which gave the plane after the clap, could be explained only by the uneven distribution of thrust engines. And this happens if the air intake fails. The problem with not starting the air intake was inherent in all A-12, YF-12 and SR-71 aircraft. In the end, Johnson decided to replace the manual control air intakes on automatic.



In 1968-1969 three more crashes occurred with SR -71. The reason was: the failure of the generator (the battery, which could provide the 30 aircraft minutes of flight, was not enough), the engine ignited and the fuel tank ignited (after fragments of wheel disks pierced it). The planes failed and another serious drawback appeared on the project's surface: firstly, there was a catastrophic lack of spare parts, and secondly, the repair of one aircraft would have hit the US Air Force "pocket" badly. It is known that the cost of maintaining one squadron of SR-71 was equal to the cost of maintaining the two tactical fighter wing wings in flight condition - that is approximately 28 million dollars.

Those "Blackbirds" who successfully passed the flight tests, were subjected to rigorous technical inspection. After landing, each flight unit passed about 650 checks. In particular, it took several hours at the two technicians for post-flight inspection of air intakes, engines and bypass devices.

During the tests, which took place up to the 1970 year, when SR-71 had been in service for four years, Lockheed suffered heavy losses, both technical and human. However, military service for the Blackbirds was just beginning.

"Blackbirds" on assignment

Approximately 1300 meters need SR-71 on the runway for a takeoff run at speed 400 km / h. After 2,5 minutes after the scout leaves the ground, at a speed of 680 km / h, he gains altitude 7,5 km. So far, the SR -71 remains at that height, only increasing the speed to Mach 0,9. At this point, the KC-135 Q air tanker refuels the Blackbird. As soon as the tanks are full, the pilot transfers the scout’s control to autopilot, as the plane must begin to gain altitude at 860 km / h, no less, no more. At altitudes of 24 km and speeds of Mach 3, the pilots again switch to manual control. So begins each mission mission.



The main points of intelligence for SR-71 were: Vietnam, North Korea, the Middle East, Cuba, and yet, despite the warnings of the Air Force command, the Soviet Union in the Kola Peninsula.

When the Blackbirds began to be sent to North Vietnam in 1968, the Vietnam War between the north and south of the country (1955 - 1975) was in full swing in its territory. From 1965 to 1973, the year went through a period of full-scale US military intervention. For SR -71 it was the largest military mission.

The Blackbirds had their own reconnaissance equipment installed. An automatic autonomous astro-inertial navigation system was installed on them, which, guided by the stars, made it possible to accurately calculate the position of the aircraft even during the day. A similar navigation system was used later in the projected, at that time, Soviet bomber T-4 bomber. The exact compliance of the flight with a given route on the SR-71 could be verified using an air data computer and an onboard computer.

In the reconnaissance process itself, the SR-71 could use several aerial cameras, a side-looking radar system (radar) and equipment capable of operating in the infrared range (thermal imaging devices). A panoramic aerial camera was also located in the nose instrument compartment. Such reconnaissance equipment allowed the Blackbird for 1 flight hours at an altitude of 24 km to survey the territory in 155 thousand km 2. This is slightly less than half the territory of modern Vietnam. As for the photographic equipment only, the intelligence officer shot several hundred ground objects in one flight. So, for example, in November 1970, in Vietnam, before the failed operation of the American military "Falling Rain" to free prisoners from Son Tay camp, the Blackbird managed to photograph the place where it was allegedly held prisoners.

The North Vietnamese artillery repeatedly tried to bring down the SR-71, according to some calculations, several hundred artillery rockets were fired at the reconnaissance aircraft, however, not a single launch was unsuccessful. Experts believed that the electronic warfare system, which suppressed the radio signal on the Vietnamese launch complex, allowed the Black-Thrush to escape the shelling. SR-71 was also subjected to the same ineffectual attack once over the territory of the DPRK.

However, the Air Force still lost several SR-71 during reconnaissance missions, although in all cases weather conditions became the cause of the accident. One such incident occurred on May 10, 1970, the Blackbird crashed over Thailand, which was home to American military bases during the Vietnam War. SR -71 just went through refueling and came across a thunderstorm front. The pilot began to raise the aircraft above the clouds, as a result of which he exceeded the permissible limit of pitch angle (i.e. the angle of raising the nose of the aircraft upwards), the thrust of the engines fell, and the aircraft lost control. The ejection seats did their work again, the crew safely left the plane.


Former pilot "Blackbird"


Missions for exploration in the Middle East during the Eighteen Day War of the Doomsday (the war between Israel on the one hand and Egypt and Syria on the other) and in Cuba were of a single character and were crowned with success. In particular, the intelligence operation in Cuba was to provide the American command with confirmation or denial of information about the strengthening of the Soviet military presence in Cuba. If this information was confirmed, the “cold war” could turn into a real international scandal, since according to the agreement signed between Khrushchev and Kennedy, it was forbidden to supply Cuba with shock weapon. SR-71 made two sorties, during which images were taken that refute rumors of deliveries to Cuba of fighter-bombers MiG-23BN and MiG-27.

The Blackbirds photographic equipment, capable of shooting in 150 radius, allowed the US military intelligence to photograph the coastal zone of the Kola Peninsula without disturbing Soviet airspace. However, once not very agile SR -71 still went too far. 27 May 1987 of the year SR -71 entered Soviet airspace in the region of the Arctic. To intercept the command of the Soviet Air Force sent a fighter-interceptor MiG-31. With a speed of 3000 km / h and a practical ceiling height of 20,6 km, the Soviet aircraft successfully forced the Blackbird into neutral waters. ” Shortly before this incident, two MiG-31 aircraft also intercepted the SR-71, but already in neutral territory. Then the American intelligence officer failed the mission and flew to the base. Some experts believe that it was the MiG-31 that forced the Air Force to abandon the SR-71. It is difficult to say how plausible this version is, however, there is reason to believe so. He could also cause the SR-71 to leave and the Soviet Circle anti-aircraft missile system, which could easily reach the Blackbird at the maximum height.


MiG-31



Circle anti-aircraft missile system


The photographs of the Blackbirds were, indeed, effective, however, it was powerless in cloudy weather. Poor visibility could be not only the cause of the failed task, but also the cause of the accident. In the rainy season, when the sky was overcast, the pilots had to maneuver in search of an open view. The loss of height on a heavy aircraft did not have the best effect on its piloting. It is for this reason that the US Air Force abandoned the idea of ​​sending SR-71 to European intelligence.

Before landing the SR -71 pilots turn on the autopilot. When the speed of the aircraft reaches 750 km / h, a decrease begins. According to the plan, at the moment when the plane starts to land, the flight speed should go down to 450 km / h, and when the runway is touched - 270 km / h. As soon as the touch occurs, the pilots release a braking parachute, with which the SR -71 overcomes the 1100 m. Then, when the aircraft’s speed drops significantly, the parachute is fired and the Blackbird continues to brake using the primary brakes. So every departure ends.

"Blackbirds" retired

At the end of the 80-ies, the first wave of the decision to deactivate the US Air Force "Blackbirds" began. The reasons turned out to be abound: a large number of disasters, high operating costs, lack and cost of spare parts, and finally, vulnerability to the above-mentioned Soviet weapons. In the autumn of 1989, the final decision was made to remove the SR-71 from service. Opponents of this decision argued that there was no alternative to the SR-71, and the spy satellites for which they had fought in Congress and in the Air Force themselves did not pay off either at a price that was several times higher than the cost of Blackbirds, or in efficiency, how SR -71 could conduct more extensive intelligence.

Practically all the planes were transferred to museums, several copies remained inactive on the bases, several planes were handed over to NASA and the Pentagon for use.



The SR Air Force SR-71, irreplaceable at that time, could not leave just like that and in the middle of the 90-s the military decided to partially return to the use of Blackbirds. In 1994, the DPRK began testing nuclear weapons. In the Senate, they sounded the alarm and asked Lockheed to resume SR-71 flights, as there was nothing to explore. The management of the company agreed, but demanded to allocate 100 million dollars. After the agreement was reached, several Blackbirds re-joined the ranks of the US Air Force. A year later, the Senate re-allocated the same amount to maintain the SR-71 aircraft in flight condition. Flights continued up to the 1998 year. However, in 1998, the Blackbirds were finally removed from service. According to news agencies, one can judge that SR-71 has been replaced by unmanned aircraft, reconnaissance aircraft and spy satellites, however, information about them is kept secret.



Such were the history of the creation, victory and defeat of the fastest manned aircraft in the world of Lockheed SR-71 (“Blackbird”).
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