Military Review

American experimental aircraft Lockheed XST Have Blue

Since the Second World War, radar has become the main means of detecting airplanes, which to this day has no equal in terms of all-weather use and range. Almost simultaneously with the first radar stations, electronic countermeasures appeared to interfere with their work. In the same period, the first attempts are being made to reduce the radar visibility of military equipment. For example, in 1944, the Germans began to cover snorkels (a device for working underwater diesel engines) and the periscopes of their submarines with radio-absorbing materials. According to some reports, in Germany, 1945 created one of the first fighters to use radio absorbing materials - the jet "Horten" No.IX. On serial samples of this "flying wing" they planned to use plywood lining, which was impregnated with a special adhesive composition containing sawdust and charcoal. The emergency defense program included the production of such fighters 20, but the crash of a single prototype aircraft and the collapse of the Third Reich interrupted these works.

A rare shot of the HB 1002 in flight - the exotic shape of the aircraft and the strong forward sweep of the wing leading edge are clearly visible. Note the faceted elevons, moving tail planes and a retractable knife antenna on the lower surface of the right wing plane.

Aviation in the first years after the war, it developed so fast that radar equipment could not keep up with them, and the task of reducing the radar visibility of aircraft became less relevant. However, some work in this area was still underway. For example, the outstanding American aircraft designer Clarencel “Kelly” Jonson, when designing the high-altitude reconnaissance “Lockheed” U-2, sought to minimize the dimensions of the machine, making it thus less noticeable to radars. In the Soviet Union, studies were conducted to reduce radar visibility through the use of special radar absorbing materials and structures. In particular, the Myasishchev Design Bureau considered ways to reduce the effective dispersion surface of the strategic ZM bomber.

With the advent of anti-aircraft missile systems equipped with high-altitude rockets and powerful radar stations in the USA and the USSR at the end of the 1950-ies, the issue of reducing the radar visibility of aircraft became again relevant.

After all, the main means that avoided detection by the enemy locators was, at that time, going to extremely low altitudes, and this led to an increase in crew fatigue, excessive fuel consumption and an overall decrease in combat capabilities. This implies the main idea of ​​a strike aircraft that has a low visibility: it must fly over a territory covered with anti-aircraft defense equipment at high and medium altitudes. As a result, the crew’s awareness of the situation is improved, the search for ground targets at long ranges is facilitated and the trajectory of the fall of bombs becomes more steep, which increases the accuracy and increases the penetrating power of bombs. The possibility of flying at medium altitudes increases the efficiency of laser illumination of targets with its own guided weapons.

The first major attempt to reduce the effective dispersion surface was the Lockheed SR-71 supersonic high-altitude reconnaissance program, which was also developed under the guidance of Johnson. The layout of the aircraft was mainly determined by aerodynamic requirements, but its features (cross-sectional shape of the fuselage, the shape of the engine nacelles, their conjugation with the wing, keels with a slight deviation to the inside) contributed to the reduction of the effective dispersion surface. The company also developed a radio absorbing internal awl-shaped construction with a plastic honeycomb core. It was used in lateral tides, elevons, and wing socks of the original version of this aircraft, which was designated A-12. On its basis, SR-71 was created (for the first time, the 22 of December of the 1964 of the year took off for the first time). His radio absorbing material was preserved in the design of the elevons and wing socks. SR-71 was covered with a special paint having a high thermal emissivity, which reduced the skin temperature during cruising altitude flight. The use of ferrite as its basis made it possible to reduce the aircraft’s radar visibility due to a more uniform reflection of electromagnetic waves. The effective dispersion surface of the SR-71 and A-12 aircraft was smaller than that of the U-2. The later developed remotely piloted aircraft D-21 (launched from the B-52 and SR-71 bomber) had even less visibility. Late versions of U-2 also covered with ferrite paint.

As a rule, U-2 and SR-71 belong to the first generation of inconspicuous aircraft, F-117A is considered a representative of the second. The creation of this aircraft was preceded by a long research and development work, which in the United States were conducted with 1965 year. The stimulus for these works was the appearance in the USSR of the C-75 and C-125 anti-aircraft missile systems, which demonstrated quite high efficiency in Vietnam and the Middle East. Hopes for on-board electronic countermeasures did not materialize - the missile systems were quickly improved, and the containers with equipment reduced the combat load of the aircraft. In the US, in 1972-1973, the civilian four-seater Eagle pistol aircraft, created by Windecker, was tested, mainly made of plastic, and its further development was experienced YE-5A. YE-5A had a fiberglass skin and internal structure using radio absorbing materials. The trials were crowned with success, and in 1973, the United States Air Force, in conjunction with the Defense Advanced Research Projects Agency, DARPA, launched secret research projects, the main purpose of which was to create a low-profile jet combat aircraft. Leading aviation concerns were given a special assignment. Boeing, LTV, Grumman, Northrop and McDonnell-Douglas responded to him. Lockheed did not qualify for the mission, as it had not been involved in fighter aircraft for the past 10 years. But despite this, she submitted for the consideration of DARPA an initiative proposal, which in November 1975, together with the project of the company Northrop, chose for further work on experimental Stealth Technology (XST, an experimental technique of low visibility). The company "Lockheed" all further work on the "stealth" was engaged in the Department for Advanced Development, located in the city of Palmdale, California (semi-official name "Skunk Works"). It was there that previously created the U-2 and SR-71.

The first prototype XST "Heav Blue" company Lockheed

The technical requirements for the XST aircraft were stringent requirements, mainly to the size of its effective dispersion surface. The analysis has shown that the use of radio absorbing materials and individual "barely noticeable" structural elements will be small, and fundamentally new solutions are required. The real way out of this situation was the widespread use of low-reflective forms. If before that the contours of the aircraft were determined mainly by aerodynamics, now it was relegated to the background, and the main attention was paid to developing the configuration of the airframe to reduce its reflectivity. The strongest reflectors of electromagnetic energy by that time were already known. These are the so-called shiny (mirror) points, which reflect the energy exactly in the direction from which the wave came, the joints of the surfaces (corner reflectors), and the sharp edges of the bearing surfaces. The low-reflective configuration of the airframe, therefore, should have been distinguished by an integral arrangement with no protruding elements and a minimum number of edges. To do this, it was necessary to ensure a smooth pairing of the fuselage and wing. Inside the wing it was necessary to place the engines and target load. In addition, it was necessary to minimize the size of the vertical flat surfaces or eliminate them (these are the strongest reflectors, since the aircraft is irradiated with ground-based radar stations mainly at a gentle angle). Keels, if they persist, deviate from the vertical. Direct radar irradiation of engine compressors is prevented by using curved air intake ducts.

To the greatest extent, these requirements are satisfied by a “flying wing” with smooth contours, which, in addition to the low-reflective configuration, has a large internal volume for installing engines and placing loads. In the United States, confirmation of the low effective dispersion surface of such a layout was first obtained at the end of the 1940-s, when coastal radar air defense systems located south of San Francisco were bombarded with a YB-49 Northrop bomber. Later during the NATO maneuvers, the Americans noted the complexity of the radar tracking of the British bomber "Vulcan", which was not inferior in size to the B-47, but its reflected momentum was several times less.

It was possible to assume that the developers of the XST aircraft would choose a scheme close to Vulcan, especially if we consider that the traditional disadvantage of this layout — insufficient longitudinal stability — could be eliminated by electric remote control systems that appeared by that time. But the magnitude of the effective dispersion surface of an aircraft is influenced not only by the geometric shape and electromagnetic properties of its surface, but also by the ratio of the dimensions of the aircraft to the wavelength of the irradiating radar, and the irradiation angle. This greatly complicates the determination for the “flying wing” of the optimal shape of the surface of complex curvature. The limited capabilities of 1970 computers, as well as the complexity of mathematical modeling of an effective dispersion surface, did not allow solving a similar problem at that time. It turned out to be easier to determine the dependence of the effective dispersion surface on the irradiation angle for the combination of flat surfaces. As a result, Northrop and Lockheed companies in their XST projects decided to use a circuit with a multi-faceted (faceted) hull shape close to the “tailless”. This configuration does not eliminate brilliant points, however, with a certain orientation of edges and flat surfaces, it makes it possible to combine reflection angles from several structural elements, thus reducing their number and removing from the sector the most likely radiation directions. This means that in these directions, the facet form ensures a significant reduction in the level of the reflected signal in all wavelength ranges of the irradiating radar station. That is, the aircraft becomes almost invisible to the air defense radar.

American experimental aircraft Lockheed XST Have Blue
HB 1002 is preparing for the first flight. The aircraft had all the features of an “invisible plane”, including a radio-absorbing coating, but did not have a bow rod - as on the first aircraft. The design of the machine was made primarily of aluminum.

Both companies presented similar XST projects. Both aircraft, in addition to the body of the facet shape, had a large-swept wing, two-fin plumage with keels tilted inward to shield the engines output nozzles. The main difference between the projects was the location of the air intakes: the Northrop company offered one dorsal air intake, located just behind the pilot’s cabin, and Lockheed two lateral air intakes.

In the first phase of the XST program, companies created models on the scale of 1: 3 to evaluate the effective dispersion surface. In 1976, they began to experience them in anechoic chambers. In the middle of the same year, Lockheed won the competition, receiving a contract to build a pair of experimental aircraft under the Have Blue program. A. Brown, an engineer at Lockheed, argued that the success of his company was largely due to the use of Soviet technical literature, first and foremost, the theoretical work of Ufimtsev, an employee of the Institute of Radio Engineering and Electronics of the USSR Academy of Sciences. His article on computational methods for determining the effective dispersion surface, published in a short-run, agency-wide journal in 1962, was translated into English in 1971 and used in Lockheed during the development of the Echo program that was used to calculate bodies of various configurations. Americans themselves write that this made it possible for 30-40 to reduce the percentage of development costs for XST, and then F-117. The tests in the chambers made it possible to specify the configuration of the aircraft, which was developed on the basis of calculations under the Echo program. After that, purging took place in high- and low-speed wind tunnels. They spent 1920 hours. After that, Lockheed manufactured a full-scale radar model, on which the design details were finally completed. In a short time it was built two flight copies.

The experimental "Have Blue" turned out to be small (the length was 14,4 m, including the nose bar) subsonic single aircraft. The aircraft was equipped with two engines, J85-GE-4A "General Electric", taken from the training deck aircraft "North American" T-2В almost unchanged. The sweep angle of the delta wing along the leading edge was 72,3 degrees. The aircraft had neither air brakes nor flaps, since their installation inevitably increased the effective dispersion surface. The only control surfaces are simple elevons and a pair of rolled-in keel piled inside. Basically, the airframe was made of aluminum, using steel and titanium in the most heat-stressed components. The pilot piloted the plane with the help of a side grip and pedals. The signals from them were perceived by the electrical remote control system, which had no mechanical duplication. During the tests, the mass of the machine varied from 4200 to 5680 kg, of which 1600 kg was fuel.

However, the design, which allowed to reduce the level of reflection of the radar signal, was the reason for the fact that the car was difficult to manage and maintain. The strength of the design also left much to be desired, the prototypes even got the nickname "Hopeless Diamond".

At the end of 1980, the aviation community, filled with rumors and bits of information, was eager to uncover the secrets of the stealth technology. Aviation-related artists painted sketches and images of a mysterious airplane. But as soon as the F-117 declassified, all of them - like the one shown in this figure - turned out to be far from reality.

The first engine launch of the experimental “Have Blue” took place at 04.11.1977 on the Skunk Works site, which was adjacent to the airport of Berbank. Due to the high secrecy of the product, the aircraft was installed between two trailers, and a camouflage net was pulled from above. Racing engines were performed exclusively at night, after the airport was closed. Then the plane was disassembled and on board the C-5A 16 November delivered to the place of flight tests - a secret base Groom Lake (Nevada). 1 December 1977 test pilot Bill Park lifted the first “Have Blue” into the sky, which was designed to study the characteristics of handling and stability. The 36 flight took place; however, the 4 of May 1978 of the year, while landing at a high vertical speed, the aircraft hit the surface of the runway. As a result of the accident, the right chassis support was seized in a semi-folded position. The pilot tried to shake it out three times, attaching it to the lane with the left wheel, but did not succeed. Then the Park rose to a height of 3 km and catapulted after producing all the fuel. The second copy, made directly for the study of the characteristics of visibility, took off on July 20 and within a year carried out the 52 flight, completing the test program in full. The final phase of testing included a “game” with real air defense, when the aircraft was tried to be “found” by all available means. Experimental aircraft "Have Blue" showed low visibility in the radar, acoustic and infrared ranges, proving the possibility of creating a subtle combat aircraft.

Aircraft performance characteristics:
Wingspan - 6,86 m;
The length of the aircraft - 14,40 m;
The height of the aircraft - 2,28 m;
Wing area - 105,90 m2;
- empty aircraft - 4060 kg;
- Maximum take-off - 5670 kg;
- fuel - 1588 kg;
Engine type 2 turbojet engine General Electric J85-GE-4A;
Thrust - 2x1338 kgf;
Maximum speed - 966 km / h;
Cruising speed - 456 km / h;
Flight duration - 1 h;
Practical ceiling - 10200 m;
Crew - 1 man.

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  1. Borat
    Borat 6 May 2013 08: 03
    Thank you for the article, usually this plane is mentioned in passing, talking about other machines created using stealth technology.
  2. Canep
    Canep 6 May 2013 08: 06
    That the F-117, that this "plane" - the directions are dead-end, the iron cannot be an airplane, let alone a combat one.
    1. Nayhas
      Nayhas 6 May 2013 10: 13
      The first airplanes also looked unprepossessing, Have Blue and Nighthawk were the "test of the pen". Now that STELS technology has become available, it is much easier to design new machines, relying on the experience of the pioneers, who started, as you say, with "irons".
      1. Canep
        Canep 6 May 2013 12: 33
        The first planes looked more like Chinese kites than iron. If the computer controlling the aerodynamics of the aircraft fails on the F-117, it will crash along the trajectory of the iron, not a single pilot without the help of a computer is simply unable to make it stably stay in the air. That's why he called it an iron.

        Quote: F-22 Raptor and the real problems of the Russian Air Force
        Crawling through C-300 is pure suicide. And no "Raptor" is not a panacea here - the US Air Force pilots will refuse to sit in the cockpit, but the one who ordered the breakthrough of enemy air defenses with the help of "Raptors" is awaiting a tribunal.

        And this quote is from the VO article, which clearly shows the "capabilities" of stealth technology in general, and the F-22 in particular.
        1. Argon
          Argon 6 May 2013 16: 05
          Maybe you won’t believe me, but the same thing happens with the Su-27 in case of failure of all branches of the energy system, and this is the fate of all air platforms with a statically unstable control model. You can still recall the F-16.
    2. smirnov
      smirnov 6 May 2013 13: 49
      It is not for nothing that 117th glued the nickname "lame goblin")))
    3. il grand casino
      il grand casino 7 May 2013 13: 08
      No, he can’t. But what an advertisement! Papuans will be in shock. However, the Serbs (they really are not Papuans) did not watch American ads. Everyone knows the result.
  3. Ak 12
    Ak 12 6 May 2013 16: 15
    It is not for nothing that 117th glued the nickname "lame goblin")))

    It smiled me too
  4. Ak 12
    Ak 12 6 May 2013 16: 18
    in 1999, a Serbian officer knocked this machine with s-125, now the fragments of f 117 in their museum))
    1. Santa Fe
      Santa Fe 6 May 2013 16: 36
      Quote: Ak 12
      in 1999, a Serbian officer knocked this machine with s-125, now the fragments of f 117 in their museum))

      F-117 has always been called "inconspicuous"... but not "completely invisible"
      As a result: 1 battle shatter on 800 sorties

      A very decent result - considering that we are talking about a subsonic clumsy car, without any reservation. Obviously, the stealth technology makes sense - no matter how they laugh at this system - these techniques are clearly visible in the design of modern Russian aircraft (PAK FA) and ships (Talvar, 20380 "Guarding", etc.)

      By the way, the officer was Hungarian Zoltan Dani
      Here he is (standing on the right), together with the pilot of the downed f-117 Dale Zelko (now both veterans are friends)
      1. Kir
        Kir 7 May 2013 14: 40
        Well, yes, flying obviously over those who have air defense is not something that is not the last but not the last but one, these are such losses, but with regards to the meaning, everything is easier here without trying to know how you will know? It’s just interesting how and why Ufimtsev’s book turned out to be with them, and he, too, seems to be not here now.
  5. Borat
    Borat 6 May 2013 17: 54
    People, you are all paranoid here! The article is just about an experimental machine! Why all this howling "who is cooler" ?! What kind of kindergarten - to be offended by the plane?
  6. Argon
    Argon 6 May 2013 18: 08
    In general, the article is not correct, it seems that the United States was moving towards STELS evolutionarily, and supposedly those distant "laboratory pterodaktels" U-2 and Blackbird were carried out with elements of a low visibility system - WELL, WHAT IS RUNNING. I frankly do not understand where this comes from, what attracts the authors to pull these two cars by the ears, black paint; well, in the case of the U-2, this is really a radio-absorbing coating, but it was applied in the mid-80s. And for the SR-71, take the trouble to find a photo of the landing after flying with 3Max. there is far from black, the coating was intended to correct the thermal barrier, it fulfilled its task one-time. Amerian strategists took care of radio signature in the early 70s. When they realized that Soviet "collective farmers" were able to kick their great-power mentality, products that were "slightly superior" to their technical horizons (S-200), there was even some kind of R&D on raking papers 30 years ago. However, we got a huge fig from our own military-industrial complex and in the price lists) they did not have a theoretical base. As a result, R&D funding for aircraft stations of active counteraction was increased, the direction for them is a breakthrough (it must be admitted as a result, now they are leaders in this topic). The impetus for STELS was not even the publication in Young Technology, but R. Reagan's decision to wrap the USSR in the arms race - Economically It was then that the CIA began to work on a young technician and from there came out for publication in an "interindustry low-circulation publication" And we are talking about the principles of the mathematical substantiation of the hypothesis, which includes two theories. ), The second is more complex and does not promise huge results, but partially confirmed by the described experiments (Conditionally "Soap dish") Both theories are taken into the development (estimate the scale of financial injections). The result of the first is F-117, the second B-1. In my opinion, it was just a running-in stand that allowed not so much to test the theory of low visibility, but to work out the algorithms of the EDSU and some of those solutions associated with an unusual layout. (which is confirmed by the manufacture of external panels made of aluminum without radio-absorbing coatings).
  7. shinobi
    shinobi 6 May 2013 18: 15
    Thank you for the interesting article. The F-117 was a good multi-purpose device against anti-aircraft systems of the middle of the century and unchecked air defense, it’s a lot to argue with. But !!! In view of the goblin’s lack of its own radar and without the support of the AWACS system, spotters are just expensive, low-flying flying iron. Actually, therefore, its purchases were quickly abandoned, and the program was curtailed.
  8. uzer 13
    uzer 13 6 May 2013 19: 24
    Invisibility for the enemy’s radar is a rather conventional concept. It’s no secret that in the meter ranges of the radar all these invisibles are clearly visible. For the U-2, this was not a problem at all - it flew at such an altitude where the SU-7 and MIG-21 could not It was possible to get it and shoot it down only with an anti-aircraft missile. But before that, these planes had for a long time been completely unpunished with reconnaissance over the territory of the USSR. For the SR-71, which had great speed and in a sense was ahead of its time, visibility for radars was also not critical .Pro HB1002 104, to be honest, this is the first time I hear. It's amazing that such a chisel could even fly into the air. And high landing speed was to be expected with such wing geometry. But other NATO aircraft, later releases, also sinned in this matter, for example, Starfighter F -XNUMX.
    1. Argon
      Argon 6 May 2013 21: 49
      Starfighter is about the same age as the MiG-21, and at the same time the main hypothetical opponent. Fortunately, they did not meet in a real battle.
  9. Sheva777
    Sheva777 7 May 2013 01: 32
    Quote: Argon
    Starfighter is about the same age as the MiG-21, and at the same time the main hypothetical opponent. Fortunately, they did not meet in a real battle.

    But didn’t they meet in Vietnam ?????
    1. Argon
      Argon 7 May 2013 03: 23
      No, the Air Force command in general used this "front-line interceptor" quite limitedly even on the territory of the United States. There was no question of sending them to Vietnam as part of any unit. But the amers generously supplied them with European allies, in particular the FRG, where they rather quickly acquired the nickname "bringing widows." The car was extremely difficult to pilot, for example, when the mechanization was removed, signs of stalling began to appear at a speed of 450 km / h.