Warszawa 2005-05-24
OKB Suchoj Su-24 / M. CCCP.
Section 1970-01-17
History.
The Sukhoi Su-24 is a Soviet supersonic missile defense and nuclear strike breakthrough aircraft. It was an attempt to create an equivalent of the American General Dynamics F-111 / FB-111.
Variable wing geometry.
The first analyzes of the use of wings with variable geometry were carried out in OKB Sukhoi around 1960. At that time, the office was designing an airplane that would become a rhombus when the wings were folded. However, this work did not go beyond the preliminary stage. As soon as the first information about the American F-111 aircraft reached the CCCP, work on the aircraft in this aerodynamic concept gained momentum again. In 1965, the design of the I-6 aircraft was created, which is a variant of the S-6 with a wing of variable geometry. At the same time, it was decided to build the S-22 I experimental aircraft (Su-7 version), which was a demonstrator of the new technology, which was flown on August 2, 1966.
The power unit of the Sukhoi T-6 aircraft.
The choice of engine parameters for the T-6 aircraft was very fateful. During the first analyses, Archip Lulka proposed to build a turbofan engine for this aircraft, which was more economical and prospective. This was contrary to the basic requirement to which the military stood firm. Namely, the plane was supposed to defeat the enemy air defense system in a five-minute flight, at an altitude of 200 m, at a speed of 1,400 km/h. To ensure such parameters, a turbofan engine would have to be larger and heavier than a single-pass engine. Finally, a single-flow engine was ordered. This held back the arrival of bypass (modern generation) engines in the CCCP for several years. Such engines were ordered only for MiG-29 and Su-27 aircraft.
As a result of the Vietnam War, many components of the General Electric J 79 engines went to the CCCP. It was decided to use this and create an engine ordered by the military for the future T-6 aircraft. Work on the engine marked AL-21 F was carried out by engineer A. M. Lulka from 1965. The initial model of the engine was to develop maximum thrust with 1 x 87.25 kN afterburning, and its first prototype was ready for trials in 1966. From 1968, subsequent AL-21 F engines went to the prototypes of Su-24 aircraft.
Variable wing geometry in T-6-2 I. 1970 year.
Trials of the T-6-1 with a fixed wing lasted, but from 1967, the designers fully switched to a variant with variable wing geometry. In August 1968, OKB Sukhoi received an official government task to develop an aircraft with variable wing geometry. According to the design, the new variant of the T-6 was to have a greater armament load and a longer range. Problems resulted, as always, from haste and poor quality of work. In the factory hall of the Sukhoi plant on Polikarpov Street in Moscow, on the edge of the Khodynka airport, the assembly of the T-6-2 aircraft, the second prototype of the T-6 with additional starting engines, was underway. It was decided to use as much as possible of what is there and introduce only the necessary minimal changes. The central part of the fuselage was cut out and the power structure of the new wing was inserted there. This was retaliated by the wing beam going through the top of the engine air intake tunnel and limiting its cross-section. As a result, the engine had to be specially modified. Converted from the T-6-2, the first prototype with a variable-geometry wing was named T-6-2 I (in the name of "variable geometry").
The wing received a fixed center wing and movable parts adjustable in the range from 16 degrees to 69 degrees. They were equipped with rich mechanization, consisting of four-section front flaps, three-section double-slot rear flaps, covering the entire span, and interrupters. There were no ailerons; their role was played by a swinging differential horizontal tail and choppers. During use, four basic positions are provided: 16 degrees – take-off and landing, 35 degrees – in typical level flight, 45 degrees – during maneuvering and 69 degrees – in flight at maximum speed.
When designing the wing for the T-6-2 I, the experience with the S-22 I experimental aircraft was used and it was made differently than in the F-111, leaving most of it stationary. Thanks to this, it was possible to place all the armament on fixed nodes, except for two small booms at the end.
The rush to build the T-6 proved detrimental to the aircraft several times. With the construction of the first T-6 prototypes at the Sukhoi plant in Moscow, preparations for serial production began at the plant in Novosibirsk. Novosibirsk was chosen because it produced Su-15 aircraft, the T-6 of which was initially intended to be a close modification. Later, as the T-6 began to evolve, there was always a requirement for the designers to change the aircraft as little as possible, as the production tooling was ready and any change meant additional difficulties and costs. That is why, for example, to this day, Su-24 aircraft have a box inside the fuselage for four RD-36-35 starting engines, which have been adopted as fuel tanks. Due to the rapid transition from a triangular wing to a variable geometry without a more radical redesign of the airframe, the intake ducts for the engines are suboptimal.
In November 1969, the T-6-2 I aircraft was transported to the Zhukovsky airport. There, on January 17, 1970, Vladimir Ilyushin took off for the first flight. In 1971, the T-6-2 I was joined by the T-6-3 and T-6-4 aircraft produced in OKB Sukhoi.
Su-24 tests and production.
In December 1971, the first serial Su-24 aircraft was built in Novosibirsk. The wings for the Su-24 aircraft were produced at the plant in Komsomolsk-on-Amur. The pre-production series consisted of 5 aircraft. The remaining four machines left the Novosibirsk plant in early 1972.
After completing the basic part of the Su-24 tests, aimed at examining the stability, controllability and performance of the aircraft, tests of its equipment and armament began. They lasted four and a half years and proceeded with great difficulties. This was the so-called stage B of the state trials, conducted at the Air Force Aviation and Experimental Center (GLIC VWS) in Akhtubinsk. Mikhail Simonov, the then deputy chief designer, was responsible for these tests in the Sukhoi team, and Vladimir Konokhov was the engineer conducting the tests. The aircraft was flown by test pilots OKB Suchoja and GLIC WWS: W. Illjuszyn, Je. Soloviev, V. Krechetov, N. Ruchladko and S. Lavrentjew. The pilot S. Lavrentiev died during these tests on August 28, 1973, together with the navigator M. Yurov. In the group of navigators there were also: N. Alfierow, W. Belych, Ł. Smyszlajew and Ł. Rudenko, W. Sidorenko.
Vladimir Ilyushin was the first to fly the Su-24 in the mountains, from the Mozdok airport in the foothills of the Caucasus, using the low-altitude obstacle avoidance system. A total of 15 aircraft took part in the trials, including the T-6-1 serving as a flying laboratory to refine the "Puma" system.
State trials were completed in July 1974, and the official decision to accept the aircraft into service with the Air Force was made in February 1975.
The main designer of the T-6 aircraft, and later the Su-24, from the beginning of the work, was Yevgeny Felsner. After his death in 1989, the development of the aircraft was taken over by Leonid Logvinov, previously responsible for the serial production of the aircraft. In the OKB project brigade, Oleg Samojłowicz was initially responsible for the Su-24 project, and later, from the early 1970s, Valeri Nikolaenko. The Su-24 was the last aircraft built under the overall management of Paweł Suchoj, who died in 1975.
The decision to start serial production was officially made in 1972, although the actual work actually started in 1968. By the end of 1972, the Novosibirsk plant had produced 28 aircraft in four production runs; 5 aircraft of the first series, 10 aircraft of the second and third series, and 3 aircraft of the fourth series. Su-24 aircraft received the name izdelije 41 at the plant.The first serial Su-24, No. 0115301, crashed during tests on June 12, 1974. The crew ejected successfully. When in 1975, state tests were completed, several dozen aircraft had already been produced, which from 1973, flew at the 4th Pilot Training Center in Lipieck. In May 1974, the first Su-24 regiment reached operational readiness – the 4th Naval Assault Aviation Regiment of the Baltic Fleet in Chernyakhovsk. serial number identification; No. 0115301 – 01 first production series, 153 Novosibirsk plant code, 01 item number.
Development – Nuclear bombs thrown upwards.
Along with the trials of prototypes and the first serial aircraft, the search for new solutions and other ways to use the base aircraft continued. Among other things, at an early stage of design, a variant was developed in which a bomb chamber was placed in the place of the starting engines for a bomb fired upwards, flying over the plane and falling on the target. This was to allow dropping a nuclear bomb in flight just above the ground. However, this idea was later abandoned.
Design of the Su-24 K board aircraft.
At the beginning of the 1970s, an on-board version of the Su-24 K was designed for the new 11-60 class aircraft carrier. However, the use of the Su-24 was abandoned quite early, because the weight of the aircraft reached 40,000 kg, and the catapults of the 11-60 aircraft carrier were calculated for a maximum aircraft weight of 30 tons. Later, the aircraft carrier project was abandoned and replaced by another 11-43.5, which today is known as the Admiral Kuznetsov-class carriers and which has a springboard, not a catapult, for launching aircraft.
Design of the Su-24 interceptor aircraft (P).
There was also a project for an interceptor version of the Su-24. This idea was abandoned because the aircraft was not suitable for this task. The aircraft was optimized for close-to-the-ground flight and had too weak acceleration characteristics for an interceptor.
Su-24 power unit.
The first serial aircraft were powered by AL-21 F (izdelije 85) engines with 2 x 87.30 kN (2 x 8,900 kG) afterburning thrust. However, during the trials, the military demanded an increase in engine thrust, and a new version of the engine, the AL-21 F 3 (izdielije 89) with 2 x 110.00 kN (2 x 11,200 kG) afterburning thrust, was fitted to the T-6-3. On serial aircraft, this engine was installed starting with the aircraft with the serial number 0415304. Later, they were also installed on previously produced aircraft. In line with the increased air flow, the side intakes have been widened, slightly rounded at the edge and moved an additional 100mm away from the fuselage.
Until the end of operation, all Su-24s fly with AL-21 F 3 or AL-21 F 3 A engines. But other engines were also tried. In February 1974, Yevgeny Solovyov flew for the first time in the T-6-8 D, the eighth T-6 prototype, with R-29 T-300 engines. It is a modification of the OKB Tumanski engine, commonly used in the MiG-23 and MiG-27 aircraft. The purpose of replacing the engines was to improve the speed of the aircraft, because the R-29 engine of the T-300 had more thrust. However, the engine also has higher fuel consumption and trials have shown that the gain in speed is small and the loss in range is significant.
The first modification of the Su-24.
Starting from Su-24 No. 0815311, more significant changes were made to the design. The most serious objection to the aircraft produced so far was their insufficient range. Therefore, in this modification, the capacity of the in-hull fuel tank No. 1 was increased by 600 liters. Thus, the total fuel capacity increased from 11,200 to 11,800 liters.
The aircraft’s equipment was also partially modernized by installing the Tester flight parameters control system instead of the existing SARPP. The extra fuel and equipment needed extra volume, so the fuselage was straightened, removing the bend behind the cockpit. Increased the number of hardpoints from 6 to 8 by adding two under the hull, one behind the other. The weight of the armament increased to 7,000 kg. In this form, the machines were produced for the Su-24 copy No. 1515328.
The second modification of the Su-24.
Subsequent copies of the Su-24 aircraft No. 1615301 received cosmetic changes that did not affect combat capabilities. The container with the braking parachute was enlarged and raised higher, the rear of the fuselage was narrowed and rounded, changes were made to the landing gear, which increased the height of the aircraft from 5.92 m to 6.192 m. These changes clearly affected the external appearance, which is why the aircraft received new ones in the West designation. The West believed that the machine had new combat capabilities, which did not turn out to be true.
The third modification of the Su-24.
In the course of using the Su-24, the conditions of the concept of its use also changed. Originally, the task specified an aircraft speed of Ma-2.35 (2,500 km/h) at high altitude. However, the maximum speed achieved during the trials was Ma-2.16. Acceleration characteristics were also weaker. At the same time, the military came to the conclusion that speed at high altitude is not needed, the most important is the speed of 1,400 km / h in flight just above the ground (200 m). For this reason, starting from the Su-24 aircraft No. 2115326, the adjustment of the air intakes was eliminated. Thanks to this, the air intake became lighter by 236 kg. Some of the weight saved had to be returned in the form of a balancing weight on frame 4, but there was still a gain. On previously manufactured aircraft, the entire adjustment mechanism remained, only its control was disconnected. From now on, Su-24 aircraft have a maximum speed limited to Ma-1.35.
The Ch-58 anti-radiation missile (number 58 from the name of the T-58 M aircraft), built especially for the Su-24, dragged on over time, and therefore in the first period the basic armament of this class was the Ch-28 rocket. The Ch-28 rocket was developed a few years earlier for the Yak-28 bomber, but ultimately it was not used. Its use in the Su-24 aircraft was temporary.
The fourth modification of the Su-24.
In the Su-24 aircraft of the last production series, from No. 2215301 to No. 2715310, the aircraft’s equipment was improved by installing the Berioza warning station, the Parol friend-foreign device and the RSDN-10 Gego long-distance navigation system. The antenna was mounted on the leading edge of the vertical stabilizer, so it protrudes forward. Later, RSDN-10 was also introduced on earlier copies. The wing profile was also slightly changed. Changes in the last production series of the Su-24 are related to the modernization of the Su-24 M, which is being developed at that time.
Su-24M (T-6M). 1977 year.
The official government decision of February 1975 on the adoption of the Su-24 for armament specified the requirements for further modernization of the aircraft. Their implementation led to the creation of the Su-24 M aircraft and the Su-24 MM and Su-24 BM projects.
The main reason for the new requirements was the change in the concept of using the Su-24 aircraft, it is an aircraft of two concepts. When the binding doctrine of the decisive role of nuclear weapons was being created and the Su-24 was subordinated to it. In the tactical and technical requirements set by the army in the 60s, the task of the aircraft was to defeat the strong enemy air defense with one nuclear bomb weighing 500 kg. Later, however, this doctrine began to change, and from the late 1960s, more and more importance was given to conventional armaments. The consequences of this for the Su-24 aircraft were two. First, it was required to carry new armaments, greater payload and range than before, and much greater accuracy in guidance systems. The new requirements also forced preparation for the WRe fight.
The new version received the designation T-6 M and the military designation Su-24 M at OKB Sukhoi.
The machine is equipped with a new PNS-24 M Tigr targeting and navigation system. The new system can work with new generations of guided missiles, including the Ch-25, Ch-29 and Ch-59 rockets as well as the KAB-500 and KAB-1500 bombs, guided by laser or television. The new system received the "Kajra" laser and television subsystem (a guillemot, a bird with very good eyesight), developed at that time for the MiG-27 K aircraft. It seemed that transferring the finished system to another aircraft would be simple, but it caused many problems . In the MiG-27 K, "Kajra" is built into the nose, on the Su-24 M it had to be installed under the fuselage of the aircraft. They wanted to do it with as little structural changes as possible, but during the tests the aircraft was vibrating. It was only after some time and after considerable rebuilding of the bottom of the fuselage that it was possible to integrate the "Kajra" and avoid vibrations.
The "Filin" passive radar for detecting and recording ground radar stations has been replaced by the new Fantasmagoria radar, suspended in the pod. The on-board computer received increased memory and a new processor.
In order to increase the survivability of the aircraft on the battlefield, it was decided to expand its defense system. Already the first serial aircraft had radio-electronic reconnaissance systems and active interference systems of the SPS series built-in or suspended in the trays. The modified aircraft was also fitted with the “Mak” anti-aircraft missile launch warning system. APP-50 thermal and radar trap launcher. The combined defense complex, controlled by the on-board computer, was named BKO-2 "Karpaty" (bortowoj complex oborony). The aircraft’s load capacity was also changed, increasing the load capacity of the beams to 8,000 kg.
Su-24 M refueling in flight, 1977.
The next task was to extend the range of the aircraft. Aerodynamic solutions (slightly narrower rear fuselage) gave little. Therefore, for the T-6 M, it was decided to build an original aerial refueling system. It is original because the T-6 M can not only refuel, but can also be a tanker itself, thanks to the installation of a unified UPAZ-A "Sakhalin" refueling unit under the fuselage.
Attempts to refuel in the air, especially for the future Su-24 M, were made at the end of the 1960s on experimental Su-15 aircraft. Two aircraft were converted for this purpose. One of them, the first serial copy of the Su-15, which was still in 2000, stood in the Sukhoi design office. The aircraft received a fuel receiver in the nose, which was initially stationary. The second, serial Su-15 TM, received a UPAZ-A fuel transfer unit under the fuselage, enabling the transfer of part of its own fuel to the other aircraft. In 1977, tests of such a solution began on the Su-24.
Air-to-air refueling expanded the aircraft’s tactical capabilities. Not only was it possible to fly over a longer distance, but also to increase the combat load carried. If the aircraft is stationed at a ground airport from which it cannot take off with the maximum weight, then the take-off is carried out with a full load of armament, but only with part of the fuel. Only in the air are the tanks filled completely.
Aerial refueling of the Su-24 can be performed in a wide range of speeds, from 500 km/h to 1,000 km/h, but the speed of 500 km/h to 700 km/h is usually assumed. From a distance of about 30 m, the receiving probe, extended from the front of the aircraft’s fuselage in front of the cabin, should be aimed at the feeding cone with a diameter of 0.70 m. The approach speed should be 1.8 – 2.0 m/s. Steer gently, because with a side impact with a side force of 90 kg, the probe may break. The approach speed cannot be too high, because you can inadvertently find yourself under the tanker and lead to a collision. If there is no connection, increase the distance to 50 m and repeat the manoeuvre.
Su-24 M tests and production.
The individual solutions of the future Su-24 M were tested on various serial aircraft, and only later were combined into one organism. Therefore, it is difficult to say where the Su-24 ended and the Su-24 M began. In the materials of the design office, January 1977 is mentioned, when the T-6 M-27 aircraft with the "Kajra" subsystem began flying.
On June 24, 1977, the T-6 M-8 aircraft, which was a converted copy of the T-6-8, took off. It was intended for aerodynamic tests of the new version and had a new longer nose and fairings of the "Kajra", "Karpaty" systems, etc., although the systems themselves were not yet on it. In total, trials of the T-6 M were carried out on seven different aircraft and were completed in November 1979.
Some of the aircraft’s characteristics deteriorated, including the maximum flight speed at an altitude of 200 m, decreased from 1,380 – 1,420 km/h for the Su-24 to 1,365 km/h for the Su-24 M.
In external appearance, the Su-24 M is most easily distinguished from the Su-24 by its 0.76 m longer nose, with a single air pressure receiver boom. In the Su-24 there is a three-story antenna system, popularly called "guś", goose. Initially, it was feared that the longer nose and greater weight of the aircraft would cause stability problems. Therefore, on the first Su-24 M, a large aerodynamic crest was added on the wing, connecting to the armament boom. In later series of Su-24 M, it was abandoned.
Production of the basic Su-24 lasted until 1983, i.e. for several years in parallel with the Su-24 M. Many improvements made for the modification were also introduced in the last Su-24. Hence, the last Su-24s already have a small air inlet for cooling the equipment in the base of the vertical stabilizer and new antennas on top of the vertical stabilizer and in the air inlets.
Simultaneously with the trials, the serial production of the Su-24 M was launched at the plant in Novosibirsk. The first serial aircraft was built in the summer of 1979, the Su-24 M received the production designation (izdielije 44). From March 1980 to May 1981, state tests were carried out again, focusing only on the operation of the weapon systems, and after removing the shortcomings, in June 1983. The Su-24 M has been officially accepted into service.
Su-24 MM and Su-24 BM programs.
The Su-24 MM and Su-24 BM projects have already gone well beyond the Su-24 framework. Su-24 MM (mataya modernization) was to be powered by two AL-31 F engines, therefore a third air intake was arranged on the top of the fuselage, because the capacity of the two side ones was insufficient. The weight of the aircraft increased by 2,000 kg, thanks to more economical engines, the range also slightly increased. However, all in all, the benefit of installing new engines was small, and the cost of modernization was quite significant, and the Su-24 MM remained only on paper.
The Su-24 BM (bolshaya modernization) became the first step to the new T-60 S strike aircraft, which also did not reach the final. Su-24 BM aircraft received only some of the planned upgrades.
Application of Su-24, Su-24 M.
Production of the Su-24/M lasted from 1972 to 1993, although by the end already in a minimal number of copies. In July 1979, Su-24 aircraft were placed in Soviet bases in the GDR.
In October 1990, 81 Su-24s (including 12 Su-24 MR) were stationed in Poland, and 24 Su-24 MR in East Germany. The largest group of aircraft was stationed in Ukraine: 288 aircraft, including 36 Su-24 MR and 8 Su-24 MP. There were 131 aircraft in Belarus (including 12 Su-24 MR), 12 Su-24 MR in Latvia, 60 in Georgia, 52 in Azerbaijan (including 23 Su-24 MR). In the European part of the Moscow state, there were 112 Su-24s in the air force, 99 aircraft were in the Baltic Fleet (including 12 Su-24 MR). According to estimates, about 120 – 150 Su-24 aircraft were stationed in the Asian part of the Moscow state, which gives a total number of over 1,000 Su-24s, including over 130 reconnaissance Su-24 MRs and 8 Su-24 MPs.
Due to the collapse of the CCCP, the dislocation of all Soviet aircraft, including the Su-24, has changed. As of October 1992; Ukraine had 257 Su-24s. Belarus took over 40 aircraft, including 12 Su-24 MRs. The others belonged to the Russian Air Force, but some of them were temporarily stationed in Belarus (82 copies) and Latvia (12 Su-24 MRs). At that time, 95 copies (12 Su-24 MR) of Su-24 belonging to the Baltic Fleet were stationed in the Kaliningrad Oblast. Several planes were also seized by Azerbaijan at Dalliar airport in June 1992.
On February 14, 1992, six Su-24 M aircraft from the 7th Bomber Aviation Regiment stationed at the Starokonstantinov airfield in Ukraine flew to Smolensk in the Moscow state. The pilots did not have permission for this flight, nor did they warn their families about it. It was their protest against the oath of allegiance to Ukraine and the inclusion of their unit in the armed forces of Ukraine. The pilots took with them to the Moscow state the banner of the unit.
Su-24 MK (kommerczeskij, aka T-6 MK). 1987 year.
It is an export version of the Su-24 M aircraft. It differs from machines typical for Soviet aviation only by using different navigation and identification equipment. Since 1987, the Su-24 MK aircraft was offered for sale. Su-24 MK aircraft were bought by Iraq – 24 copies. As a result of the wars, all undamaged machines went to Iran. Libya ordered 15 machines but ended up buying only 6. Syria bought about 22 machines, according to Mossad data. There is no information about the combat use of Su-24 MK aircraft.
Su-24 M 2 – Modernization of Su-24 / M. 1998 year.
In the mid-90s, the modernization of machines owned by the Moscow state began. Until 2000, about 5 machines were modernized. The aircraft were marked Su-24 M 2. The modernization in 1998 was developed by the private company Gefest and T. The main changes consisted in; replacement of the Orbit-10 on-board computer with SWP-24, installation of the A737 GPS receiver and installation of the KAI-24 head-up indicator. The aircraft modernized in this way are used by the experimental center in Akhtyubinsk and the training center in Lipetsk. On the basis of this modernization, an order for the delivery of 22 aircraft referred to as Su-24 MK1 for Algeria is being implemented. It should be noted that the machines for this country are not new, but come from the stocks of the Moscow State Aviation. Of course, after refurbishment at the plant in Novosibirsk. By the end of 2003, 13 copies had been delivered to an African user.
Usage of the Su-24 after 2000.
At the beginning of the 21st century, Su-24 aircraft had: Moscow state: about 540 copies in the air force and about 100 copies in the navy. Ukraine (January 1, 2002) had 129 copies in the air force. Belarus about 35 copies. Kazakhstan about 35 copies. Uzbekistan about 35 copies. Algeria 38 strike units (including about 13 Su-24MK1s) and 3-4 reconnaissance Su-24 MRs. Iran about 24 examples (ex-Iraqi). Libya: 6 copies. Syria 20 copies.
So far, apart from the flight of Iraqi Su-24 MKs to Iran, combat aircraft have been used during the CCCP intervention in Afghanistan in 1982. The planes bombed selected targets operating from airfields located within the CCCP and did not suffer any losses. The second use of Su-24 aircraft by the Soviet army took place in Chechnya. Here, too, planes took off from airports in CCCP, but at least 4 Su-24 aircraft were lost during combat tasks.
Written by Karol Placha Hetman