The Sukhoi Su-27 (Russian: Сухой Су-27) (NATO reporting name: Flanker) is a twin-engine supermanoeuverable fighter aircraft designed by Sukhoi. It was intended as a direct competitor for the large United States fourth generation fighters, with 3,530-kilometre (1,910 nmi) range, heavy armament, sophisticated avionics and high manoeuvrability. The Su-27 most often flies air superiority missions, but is able to perform almost all combat operations. Complementing the smaller MiG-29, the Su-27's closest US counterpart is the F-15 Eagle.
In 1969, the Soviet Union learned of the U.S. Air Force's "F-X" program, which resulted in the F-15 Eagle. The Soviet leadership soon realised that the new American fighter would represent a serious technological advantage over existing Soviet fighters. What was needed was a better-balanced fighter with both good agility and sophisticated systems. In response, the Soviet General Staff issued a requirement for a Perspektivnyy Frontovoy Istrebitel (PFI, literally "Prospective Frontline Fighter", roughly "Advanced Frontline Fighter"). Specifications were extremely ambitious, calling for long range, good short-field performance (including the ability to use austere runways), excellent agility, Mach 2+ speed, and heavy armament. The aerodynamic design for the new aircraft was largely carried out by TsAGI in collaboration with the Sukhoi design bureau.
When the specification proved too challenging and costly for a single aircraft in the number needed, the PFI specification was split into two: the LPFI (Lyogkyi PFI, Lightweight PFI) and the TPFI (Tyazholyi PFI, Heavy PFI). The LPFI program resulted in the Mikoyan MiG-29, a relatively short-range tactical fighter, while the TPFI program was assigned to Sukhoi OKB, which eventually produced the Su-27 and its various derivatives. The TPFI program is similar to the American F-X program, which resulted in the F-15 Eagle, while the LPFI program is similar to the Lightweight Fighter program, which spawned the F-16 Fighting Falcon and the Northrop YF-17, which itself led to the F/A-18 Hornet.
The Sukhoi design, which was altered progressively to reflect Soviet awareness of the F-15's specifications, emerged as the T-10 (Sukhoi's 10th delta wing design), which first flew on 20 May 1977. The aircraft had a large delta wing, clipped, with two separate podded engines and a twin tail. The ‘tunnel’ between the two engines, as on the F-14 Tomcat, acts both as an additional lifting surface and hides armament from radar. While being developed, it was spotted by a spy satellite at the Zhukovsky flight test center near the town of Ramenskoe, resulting in the temporary codename of 'Ram-K'. It was believed that the Ram-K was being developed in two versions: a swing-wing fighter similar in function to the Grumman F-14 and a two-seat fixed wing interceptor aircraft which in fact turned out to be the unrelated Mikoyan MiG-31. Su-27 (T-10) in front of a Mil Mi-12.The T-10 was spotted by Western observers and assigned the NATO reporting name 'Flanker-A'. The development of the T-10 was marked by considerable problems, leading to a fatal crash on 7 May 1978. Extensive redesigns followed, and a heavily revised version, the T-10S, made its first flight on 20 April 1981. This, too, had considerable developmental problems, leading to another fatal crash on 23 December 1981.
Between 1986 and 1990, using a specially configured prototype aeroplane T10-15, which became known as P-42, the design bureau's test pilots established 41 IAF-registered world records of rate-of-climb and flight altitude, some of the records being absolute.
In June 1989, the Su-27 and Su-27UB were for the first time shown abroad, at the Le Bourget air show. The design bureau's test pilots V.G. Pugachov and Ye.I. Frolov demonstrated to the international aviation community the superior manoeuvrability of Sukhoi planes. From that day on, Su-27 type planes have been participating in the most prestigious international aviation events, invariably demonstrating the highest level of achievement in the Russian aircraft industry.
Another proof of the plane's superior combat performance is the Su-27's commercial success in the global marketplace. Starting in 1991, the production facilities in Komsomolsk-on-Amur and Irkutsk have been producing export variants of the Su-27: the Su-27SK and Su-27UBK. Models of these types have since 1992 been exported to China, Vietnam, Ethiopia and Indonesia, and Su-27SKs have since 1998 been produced as the F/J-11 in China under licence in accordance with intergovernmental agreement. The first licensed-production plane, assembled in the town of Shenyang, was flight tested on 16th December 1998.
As a baseline design, Su-27 had a high reconfiguration potential, which allowed the Design Bureau to start work on enhanced versions.
Left side scheme of a Sukhoi Su-27 Flanker B, first production seriesLeft side scheme of a Sukhoi Su-27 Flanker B, last production seriesRussian fighter Su-27K (later designated Su-33) on the deck of Admiral Kuznetsov*T10 ("Flanker-A"): Initial prototype configuration.
- T10S: Improved prototype configuration, more similar to production spec.
- P-42: Special version built to beat climb time records. The aircraft had all armament, radar and paint removed, which reduced weight to 14,100 kg. It also had improved engines.
- Su-27 Preproduction series built in small numbers with AL-31 engine
- Su-27S (Su-27 / "Flanker-B"): Initial production single-seater with improved AL-31F engine. The "T10P"
- Su-27P (Su-27 / "Flanker-B"): Standard version but without air-to-ground weapons control system and wiring and assigned to Soviet Air Defence Forces units. Often designated Su-27 without -P.
- Su-27UB ("Flanker-C"): Initial production two-seat operational conversion trainer.
- Su-27SK: Export Su-27 single-seater.
- Su-27UBK: Export Su-27UB two-seater.
- Su-27K (Su-33 / "Flanker-D"): Carrier-based single-seater with folding wings, high-lift devices, and arresting gear, built in small numbers. They followed the "T10K" prototypes and demonstrators.
- Su-27M (Su-35/Su-37, Flanker-E/F): Improved demonstrators for an advanced single-seat multirole Su-27S derivative. These also included a two-seat "Su-35UB" demonstrator.
- Su-27PD: Single-seat demonstrator with improvements such as inflight refuelling probe.
- Su-27PU (Su-30): Two-seat limited production machine with improvements such as inflight refuelling probe, fighter direction avionics, new flight control system, and so on.
- Su-30M / Su-30MK: Next-generation multirole two-seater. A few Su-30Ms were built for Russian evaluation in the mid-1990s, though little came of the effort. The Su-30MK export variant was embodied as a series of two demonstrators of different levels of capability. Versions include Su-30MKA for Algeria, Su-30MKI for India, Su-30MKK for the People's Republic of China, and Su-30MKM for Malaysia.
- Su-27SM (Flanker-B Mod. 1): Mid-life upgraded Russian Su-27S, featuring technology evaluated in the Su-27M demonstrators.
- Su-27SKM: Single-seat multirole fighter for export. It is a derivative of the Su-27SK but includes upgrades such as advanced cockpit, more sophisticated self-defense electronic countermeasures (ECM) and an in-flight refuelling system.
- Su-27UBM: Comparable upgraded Su-27UB two-seater.
- Su-27SM2: 4.5-gen block upgrade for Russian Su-27, featuring some technology of the Su-35BM; it includes Irbis-E radar, and upgraded engines and avionics.
- Su-27SM3: The same as the Su-27SM but in contrast is newly-built rather than a mid-life upgrade.
- Su-32 (Su-27IB): Two-seat dedicated long-range strike variant with side-by-side seating in "platypus" nose. Prototype of Su-32FN and Su-34 'Fullback'.
- Su-27KUB: Essentially an Su-27K carrier-based single-seater with a side-by-side cockpit, for use as a naval carrier trainer or multirole aircraft.
- Su-35BM/Su-35S: Also dubbed "The Last Flanker" is latest development from Sukhoi Flanker family. It features newer avionics and new radar.