Su-27

The Sukhoi Su-27, known to NATO as the Flanker, is a Soviet twin-engine fighter built for supersonic speed and supermaneuverability. It was designed to go head-to-head with large American fourth-generation jets like the F-14 Tomcat and F-15 Eagle, offering a 3,530-kilometer range, heavy weapons, advanced electronics, and high agility. Its main job was air superiority, but later versions could handle nearly any aerial combat role. It was meant to work alongside the lighter MiG-29.

The Su-27 entered Soviet service in 1985. Its primary mission was long-range air defense against U.S. bombers like the B-1B and B-52, protecting Soviet coasts from carrier-based aircraft, and escorting Soviet heavy bombers such as the Tu-95, Tu-22M, and Tu-160.

The design grew into a whole family: the Su-30, a two-seat all-weather fighter for both air-to-air and ground attack; the Su-33, a carrier-based fleet defender; the Su-34, a side-by-side two-seat strike fighter; and the Su-35, an upgraded air superiority and multirole fighter. A thrust-vectoring prototype, the Su-37, was also built. China produced a licensed copy, the Shenyang J-11.

Development began in 1969, when the Soviet Union learned of the U.S. "F-X" program that led to the F-15. Soviet leaders saw that this new American fighter would outclass existing Soviet designs. They needed a balanced fighter with agility and advanced systems. The General Staff issued a requirement for an "Advanced Frontline Fighter" (PFI), with ambitious goals: long range, good performance from rough runways, excellent agility, Mach 2+ speed, and heavy armament. The aerodynamic work was mostly done by TsAGI with Sukhoi.

The PFI spec was too costly and demanding for a single aircraft in the needed numbers, so it was split into two: a lightweight version (LPFI) became the MiG-29, a short-range tactical fighter, and a heavy version (TPFI) went to Sukhoi, eventually producing the Su-27 and its derivatives.

Sukhoi’s design, updated as they learned more about the F-15, became the T-10, first flown on 20 May 1977. It had a large clipped wing, two separate podded engines, and twin tails. The tunnel between the engines, like on the F-14, acted as extra lift and hid weapons from radar. The T-10 used an "integral scheme" developed by Sukhoi, TsAGI, and SibNIA, aiming for optimal performance with 3-5% longitudinal instability in subsonic flight and fly-by-wire controls for future heavy fighters. Stability issues, like those seen in the YF-22 and JAS-39 Gripen, were fixed by limiting load factor and angle of attack during FBW development. Controlled high-angle-of-attack maneuverability—supermaneuverability—was emphasized after a 1980s study showed its value in close combat.

The first prototypes were T-10-1 and T-10-2, powered by Lyulka AL-21 turbojets with ogival wings. The aerodynamic layout proved unsatisfactory, confirmed by T-10-1’s first flight on 20 May 1977. It finished trials in November 1983 and went to the Soviet Air Force Museum in late 1985. T-10-2 first flew on 16 May 1978, but crashed on 7 July 1978, killing the pilot after exceeding G limits and breaking up when the stick was pulled back. Western intelligence initially called these "Ram-K," spotting them at Zhukovsky’s Ramenskoye airfield; they later got the NATO name "Flanker-A." A second batch—T-10-3 and T-10-4—was built by KnAAPO starting in 1978, fitted with the intended Lyulka AL-31 turbofan and redesigned nacelles. T-10-3 first flew on 23 August 1979 after engine delays, and in 1982-83 it did land-based STOBAR tests for naval aviation. T-10-4 tested avionics and armament with the Mech radar. Tests with T-10-4 and later T-10-10 revealed serious radar flaws. A third batch of AL-21-powered aircraft—T-10-5, T-10-6, T-10-9, T-10-10, T-10-11—was built for avionics tests. T-10-6 was destroyed in a ground fire in October 1980 from a leaking fuel line. T-10-10 and T-10-11 tested radar, weapons control, and targeting. These prototypes showed that avionics weight, AL-31 fuel consumption, and aerodynamics fell short of requirements.