The modernized Su-27SK single-seat, highly-maneuverable, multi-purpose fighter is designed to attack aerial and ground targets in standard or adverse weather, in daylight or at night, with the use of both guided and unguided weapons in independent or group operations as part of air superiority and aerial reconnaissance missions in continental and maritime air-operation theaters.
The Su-27SK is an export version of the Su-27, one of the best fighters in its class, produced since 1985.
In the early 1970s, many countries launched programs for the design and production of fourth-generation fighters. In Russia, efforts to design an advanced, next-generation fighter was started in 1969 at the initiative of the Sukhoi Design Bureau under the leadership of O. Samoilovich. Soon after, the government decided to back a program for the design and production of an advanced multi-purpose fighter that would match and even surpass the US F-14, F-15, F-16 and F-18 fighters from McDonnell Douglas in terms of combat potential. To achieve target advantages, it was first required to incorporate cutting-edge concepts early in design, such as the use of integral airframe configuration and arrangement of engines in spread out nacelles under the fuselage. The aircraft’s maneuverability performance in close air combat should considerably improve as a result of implementation of the lateral relaxed longitudinal static stability and balance concept through the use of a fly-by-wire control system (EDSU).
The conceptual planning of such an airplane was completed by design bureaus headed by P. Sukhoi, A. Mikoyan and A. Yakovlev in 1971-72. After a bid, two concepts were chosen: the T-10 (by Sukhoi DB, a heavy tactical fighter named Su-27) and the “9-12” (by Mikoyan DB, a light fighter named MiG-29).
The program for design and production of the Su-27 as a next-generation airplane was one of the largest national defense programs of the USSR in the 1970s. With the vast funds earmarked by the government for its implementation, enterprises in the domestic aircraft industry and related sectors were able to study, and introduce, a number of new manufacturing processes, and many plants could be re-equipped. A huge number of joint contractors were engaged in the cooperative effort under the Su-27 program nationwide.
The extensive use of innovations and advanced technology is a distinctive characteristic of each of the airplane’s systems.
-The power generation designed specifically for the Su-27 by Lyulka Design Bureau comprises two next-generation AL-31F afterburning turbofan engines with extremely high weight, thrust, and efficiency performance, providing the airplane with an unprecedented thrust/weight ratio and thus ensuring high acceleration, rate-of-climb, and maneuvering capabilities. The engines could only be created with the introduction of advanced materials and processing technology: new titanium alloys, heat-resistant steels, single crystal blades, special coatings, etc.;
-In order to reduce weight, set as one of the most critical parameters of the fighter, a great scope of work was completed towards the creation of new components for the various systems of the Su-27;
-The Design Bureau had to address problems associated with the insufficient development level of the domestic avionics-component base, resulting in the excessive weight and dimensions of parts, through improved design and arrangement concepts, as well as cutting-edge technologies;
-Avionics equipment for the Su-27 was designed with the extensive introduction of digital data processing with on-board computers, in due consideration of principles envisioning the wide combination of different systems in terms of functionality and application. For instance, the weapons-control system included, in addition to a radar target-location channel (multi-functional side-sweeping airborne radar), an independent data channel – infrared search-and-track station;
-Next-generation mid-range (K-27E) and short-range (K-73) guided missiles were developed as a part of the special-purpose Su-27 weaponry renovation program.
N. Chernyakov was appointed Chief Designer of the Su-27 Program in 1973. In 1973-74, the Design Bureau continued to work on selecting and specifying the optimal aerodynamic configuration of the airplane and its individual components, and the scope of systems, equipment ,and weaponry. In order to test the aerodynamics, power generation, control systems, attack-and-navigation equipment, and weaponry of the Su-27, the Design Bureau and Flight Testing Center designed and tested dozens of “flying laboratories.” Sukhoi DB had never conducted experiments at such a scale or level of realism for testing the systems of new aircraft before. Large-scale wind tunnel examinations of models were also conducted by the Central Institute of Aero-Hydrodynamics (TsAGI), Siberian Aeronautical Research Institute (SibNIA), and Moscow Aviation Institute (MAI).
The main scope of front-end engineering was completed by the beginning of 1975, at which point detailed designs were started. The delivery of detailed engineering drawings were given to the aircraft plant in Komsomolsk-on-Amur, which was designated as the lead manufacturing site for production of the Su-27. M. Simonov was appointed Chief Designer of the Su-27 program in February 1976. By that time, the Design Bureau was already in the process of manufacturing the first three engineering development models of the T-10 (two flight models and one element strength test), conducting marginal testing of all of the major systems of the future airplane on full-size test beds. At the same time, airplane pre-production activities started. The first test item T-10-1 was manufactured in early 1977, and it was first flown by the Design Bureau’s Chief Pilot V. Ilyushin on May 20, 1977.
A preliminary design review was successfully completed by the Design Bureau in October 1977. The second test item, T10-2, entered testing in May 1978. The first two flight models of the Su-27 were equipped with AL-21FZAI engines. The T10-3 and T10-4, equipped with standard AL-31F engines, were ready for testing in 1979.
In total, 11 test elements for the T-10 were manufactured from 1977 to 1982. In order to accelerate this work, the decision was made to employ nearly the whole preproduction batch of Su-27 manufactured by the production plant in 1980-81 in factory tests. Those airplanes were subsequently used by the DB and Flight Testing Center for the testing of individual airplane systems. The Su-27 was formally accepted by the military for official tests in December 1979.
The version approved for production was an airplane of normal aerodynamic design and integral arrangement, with an ogee-shaped wing with developed extension and compound sweep along the leading edge, an all-movable horizontal tail mounted on booms as an extension of the centerwing, and a twin vertical tail mounted in the aft fuselage section on engine nacelles. Engine air intakes were adjustable, with high positioning of the horizontal deceleration lobe, spread to the sides from the airplane centerline, and suspended under the centerwing. This arrangement of inlet devices allowed for the achievement of high flow-stability performance at high angles of attack, which was essential for an airplane designed for air-combat maneuverability. The engine nacelles located in the tail section were an extension of the air intakes. Landing gear was of a normal arrangement, with a nose and two main gears. The arrangement of the main landing gear bays was very difficult to design, given the arrangement of the version selected. Ultimately, a place to arrange the bays was finally found in the “air shadow” of the centerwing, above the intake ducts, the gears being retracted along with the mechanical turn of the wheel. The doors additionally served as airbrakes.
However, the airplane ultimately entered production in a different configuration. In the course of flight testing, it became clear that the original arrangement had significant drawbacks: the airplane did not meet the design specification for certain parameters, and even fell behind the F-15 in some respects. The designers faced a dilemma: should they prepare the airplane for production and deliver it to the customer as it was, or undertake significant modifications which would result in suspension of the production that had been started, and in the commissioning of a full-scale pre-production process, i.e. in the inevitable disruption of the production schedule.
E. Ivanov, DB General Designer, supported the initiative put forward by M. Simonov and made the difficult decision to commission a substantial rework of the airplane. The Ministry of Aerospace Industry opposed the decision with criticism, but Deputy Minister I. Silayev supported the Design Bureau’s position. As a result, the relevant decision was made in January 1978, and the Design Bureau stated the detailed design stage using a new arrangement version – the Т-10S (production version). Design specialists from SibNIA and aerodynamics experts from TsAGI took active part in the difficult work.
Essentially, the changes involved:
-transition to a trapezoidal wing shape, with a swiveling leading edge and flaperon;
-relocation of the airplane accessory box to the “back” of the engine, which allowed for its “hiding” in the centerwing air shadow, reducing the airplane’s master cross-section;
-use of a new main landing gear retraction power-flow diagram;
-the relocation of fins from engine nacelles to fuselage booms, thus improving attachment arrangement and tail effectiveness.
Changes in the arrangement enabled a reduction in airplane weight, air drag, as well as a substantial improvement in wing load-bearing performance and its adaptability to various modes of flight and, as a result, improvement in the airplane’s longitudinal lateral stability performance.
From 1979 to 1981, the Design Bureau’s Su-27 Program was led by A. Kolchin, succeeded by A. Knyshev, who was appointed Chief Designer in 1981.
The first test item of the Su-27s production configuration, the T10-7, which incorporated the experience of T-10 development and related test data, took off for its first flight piloted by V. Ilyushin on April 20, 1981. Results of the tests confirmed the exceptionally-high performance of the new airplane. Combined modifications produced a cumulative effect in the T-10S – the resulting airplane possessed high flight performance and excelled rivals in its class.
The first production of a Su-27 was flight tested at the production site by the Design Bureau’s test pilot A. Isakov on June 1, 1982. Official tests of the Su-27 were accomplished in December 1983, and the first produced airplanes were delivered to air force units in June 1985. Pilots of the 60th Fighter Wing of the Far Eastern Command were the first to receive Su-27 among all combat units. By 1989, Su-27 fighters were in operational service in 16 combat units of the USSR Air Force and Air Defense. According to commanders and airmen of the retrained units, the retraining process went smoothly and the new Su-27 was exceptionally easy to master – the airplane turned out to be quite accessible to pilots with even moderate qualifications, despite the fact that it was vastly superior to all older-generation planes in terms of equipment level and complexity of systems and weapons.
In 1990, after all of the major issues identified during tests had been completely resolved, the Su-27 was officially accepted by the Air Force and Air Defense.
It took seven years to design and manufacture the first two test airplanes, and factory testing and flight tests took seven more years. A total of 23 airplanes were engaged in tests at different times. Thus, 16 years passed from the start of design to the commencement of Su-27 deliveries¬ – following years of hard work by numerous teams at industry enterprises, military representatives and the Air Force Testing Institute.
As the baseline model, the Su-27 offered much room for further development in terms of arrangement, and that enabled the Design Bureau to mount an effort to modify and refine the airplane. Subsequently, the DB developed an operational training airplane, a fighter-bomber, a multi-purpose and a naval fighter on the basis of that arrangement.
The operational training (two-seat) version of the Su-27 had been worked on since 1976, and the conceptual design of the Su-27UB (factory code T-10U) successfully passed design review in 1978. The first test prototype of the dual-cockpit version was manufactured at the production facility in Komsomolsk-on-Amur and then sent to Moscow for modifications in the spring of 1984. The design Bureau’s test pilot N. Sadovnikov operated the first flight on the T10U-1 on March 7, 1985. Official tests of the airplane were conducted from 1985 to 1987. Production of the preproduction batch of Su-27UB was arranged at the Komsomolsk-on-Amur plant, and in 1985, production of the dual cockpit version was transferred to the Irkutsk Aircraft Production Association (IAPO) by order of the Aerospace Industry Ministry. The first production of the Su-27U completed flight tests at the Irkutsk plant on September 10, 1986. It was flown by test pilots G. Bulanov and N. Ivanov. Production Su-27UBs were delivered to operational units in 1987.
Test pilots of the DB established 41 rate-of-climb and altitude records officially registered by FAI on the specially-modified test T10-15 aircraft designated as P-42 from 1986 to 1990, some of which would go on to become all-time records. The aerobatic demonstration team “Russkiye Vityazi” (“Russian Knights”) was formed in 1989 with six Su-27 airplanes.
The Su-27 and Su-27UB were first demonstrated outside the USSR at Le Bourget Air Show in June 1989. DB test pilots V. Pugachev and E. Frolov showcased the high maneuverability performance of Sukhoi airplanes for the international aviation community. Since then, Su-27-type airplanes have participated in the most prestigious international air shows and exhibitions, invariably demonstrating the highest level of development of the domestic aviation industry.
The commercial success of the Su-27 on the global market is another confirmation of the excellent combat characteristics of the airplane. Since 1991, two export versions of the Su-27 have been produced at plants in Komsomolsk-on-Amur and Irkutsk: the Su-27SK and Su-27UBK. These airplanes have been exported to China, Vietnam, Ethiopia, and Indonesia since 1992. Licensed production of the Su-27SK under the designation F/J-11 was set up in China in 1998. The first licensed plane assembled at the plant in Shenyang was flight tested on December 16, 1998.
A great contribution to the airplane’s creation was made by the General Designers: P. Sukhoi, A. Lyulka, A. Ivanov, M. Simonov; the chief designers of the airplane and project coordinators: N. Chernyakov, O. Samoilovich, A. Kolchin, A. Knyshev, V. Kobchenko, V. Grishin; and Sukhoi DB’s test pilots: V. Ilyushin, E. Solovyov, N. Sadovnikov, A. Komarov, V. Pugachev, and others.
The main design features of the Su-27SKM (modernized) airplane are:
The airplane is built with a normal aerodynamic design and features so-called integrated layout. It has a mid-set trapezoidal wing with small aspect ratio, provided with developed extensions and smoothly interfaced with the fuselage forming a single monocoque hull. Two AL-31F-type bypass turbojet engines with afterburners are accommodated in individual nacelles mounted under the load-bearing body of the airplane and spaced so as to prevent any mutual aerodynamic interference, as well as leaving the ability to mount missiles between them. It has an all-metal construction, with extensive use of titanium alloys. The fuselage is "semi-monocoque.” The nose is drooped. The pilot is accommodated in an ejection seat, enabling emergency ejection across the entire range of altitudes and flight speeds.
The landing gear fairings transition smoothly into tail booms that serve as platforms for the installation of all-flying tailplane panels with a straight axle, twin-fin vertical stabilizer spread to the outer faces of tail booms, and there are ventral fins under the booms.
The airplane design is geared towards an "electronic stability" concept and does not have conventional longitudinal axis control – a fly-by-wire control system (SDU) is used instead. The airplane has a tricycle retractable landing gear, with one wheel on each gear. It is equipped with a flight refueling system.
The airplane’s Weapon Control System (WCS) provides for the detection, tracking and onboard-weapon attacking of aerial, ground and sea-surface targets in all weather conditions, in daylight or at night. It includes two main subsystems: a radar aiming system and optoelectronic aiming system for controlling air-to-air and air-to-surface weaponry. WCS supports the use of a wide range of aircraft weapons.
In air-to-air mode, the radar station provides for: the detection and tracking of aerial targets against sky and ground backgrounds at a range of up to 100 km (up to 10 aerial targets can be tracked in one run); search for aerial targets; recognition of the state identity of detected targets; attack with short- and mid-range missiles with different guidance systems; the search, locking and tracking of visual targets in close maneuvering air combat. In air-to-surface mode, the radar station provides for all-weather detection and the determination of coordinates of ground and sea-surface targets, which can be detected by radar.
The infrared search-and-track (IRST) station, which uses a combination of surveillance-and-tracking heat-source direction finders and laser range-finding target designators, is used for aerial target tracking by thermal signature and finding the range to an aerial or ground target with a laser beam, and can also be used for the laser illumination of a ground target when the air-to-surface guided missiles with laser seekers are used.
The pilot irradiation warning system provides for the detection and classification of radio-emitting systems and guides X-31P missiles with the passive seeker used to destroy such systems.
The Weapon Control System (SUV-P) provides homing for guided and unguided weapons used against ground targets.
The core elements of the cockpit’s single information/control environment are two color multi-function displays (MFDs), a multi-function indicator and control panel with bezel buttons and a head-up display, where all the required nav/attack and aeronautical information, as well as airplane systems operation data, are displayed in image and digital formats. Along with the MDF, the cockpit control panel accommodates conventional electromechanical displays that mainly have backup functions.
The helmet pointing-and-aiming system allows for the pilot to guide missiles with a turn of the head towards the expected target.
|wing span (m)||14.июл|
|maximum take-off weight (kg)||30,45|
|normal takeoff weight (including 2 x R-27R1 + 2 x R-73E missiles, and 5,270 kg of fuel) (kg)||23,74|
|maximum landing weight (kg)||21|
|landing weight limit (kg)||23|
|maximum combat payload (kg)||8,000 on 10 hardpoints|
|Engine’s main performance data|
|type, model||afterburning turbofan engines, AL-31F|
|maximum unboosted thrust (kgf)||2 х 7,870|
|maximum reheated thrust (kgf)||2 х 12,500|
|maximum speed near ground (km/h)||1,4|
|maximum Mach number at altitude (km/h)||фев.15|
|maximum range (2xR-27R1 and 2хR-73E missiles launch at the midway) near ground (km)||1,34|
|maximum range (2xR-27R1 and 2хR-73E missiles launch at the midway) at cruise altitude (km)||3,53|
|Service ceiling (m)||17,75|
|maximum endurance unrefueled (h)||04.май|
|shortest TO run (normal take-off weight) (m)||450|
|landing roll (normal landing weight, using braking parachute) (m)||700|
|maximum load factor||9|
|to first overhaul (h)||1|
|Gunnery||30mm GSh-301 gun|
|guided air-to-air||R-27R1 (ER1), R-27T1(ET1), RVV-AE, R-73E|
|guided air-to-surface||X-31P(A), X-29TE(L, T)|
|Smart bombs||KAB-500KR, KAB-1500KR|
|unguided projectiles||type S-8, type S-13, type S-25|