In the mid 1970s, Soviet air defense forces faced a daunting challenge. Not only were their front-line MiG-23 and MiG-25 interceptors unable to effectively intercept low flying, high-speed bombers and cniise missiles, but the introduction of modem air superiority fighters like the F-15 Eagle also showed that they were woefully inadequate in air combat performance as well. To meet this challenge, the Soviets embarked on a massive development program that would eventually culminate in the MiG-29 and its larger, more capable comrade, the Sukhoi Su-27 Flanker.
First flown in 1977, the Flanker had a protracted and difficult development period with several crashes costing the life of at least one test pilot and resulting in an extensive redesign of the prototype. The redesigned prototype flew in 1981 and proved so successful that a stripped down version, designated the P42, broke many of the world records for time- to-altitude previously held by the F-15 Streak Eagle.
In keeping with the main design goal of producing a very agile air combat fighter, the Su-27 has two very powerful engines rated at 30,000 pounds of thrust each, given the plane a thrust-to-weight ratio of over 1.1:1 at normal take-off weight. The engines are equipped with auxiliary intake ducts for high angle-of-attack maneuvers and also incorporate retractable louvers inside the intakes to prevent foreign object damage prior to take off.
The large wing is blended to the fuselage with leading edge extensions and is equipped with leading and trailing edge flaps that automatically adjust the wing camber for high lift and low drag at all times, giving the Flanker superior control at low airspeeds and high angle-of-attack.
The flight controls are actuated by a triply redundant fly-by-wire system, the first such system in a Soviet fighter, necessary because the Su-27 is statically unstable and can therefore perform high pitch rate maneuvers. In size, the Flanker is slightly larger than the F15, but can sometimes be mistaken for an F-14 or F-16 from certain angles because of its prominent leading edge extensions and low-slung engines.
In another first for Soviet fighters, the Su-27 cockpit is large, roomy, and provides the pilot with an excellent allaround view. Although the cockpit instruments consist mainly of 1970s-era round gauges, a large HUD with helmet mounted sight and stick-and-throttle controls give the pilot modern capabilities.
The primary detection and fire control system is a powerful pulse Doppler radar with the look-down ability essential for a modem interceptor directed through the largest dish (4 foot diameter) of any operational fighter. The effectiveness of the radar is hampered by the lack of sophisticated signal processing software and advanced IC technology found in contemporary Western fighters.
Supplementing the radar is an advanced infrared search and track system (IRSTS) with laser rangefinder identical to that found on the MiG-29. All of the Flanker's sensors are integrated with the helmet mounted sight, greatly enhancing their effectiveness by allowing offboresight target tracking and weapon launch.
Missile Load-out
Keeping in mind its mission of air defense over the largest nation on Earth, it is not surprising that the Su-27 carries a larger missile load than any Soviet and most Western fighters. Normal loadout comprises 10 missiles: 2 AA-10A medium range RHMs on stations 9 and 10, 2 AA-10B long range RHMs on stations 4 and 5, 2 AA-10C medium-range IRMs on stations 3 and 6, and 4 AA-11 short-range IRMs on stations 1, 2, 7, and 8. Just as in the MiG-29, a 30mm laseraimed internal cannon with 200 rounds is also carried.
Since all the stores pylons are occupied by missiles, the Flanker relies totally on a 10,000 kilogram internal fuel supply, giving it a range of over 2,500 miles. This is a necessary feature due to the extremely long distances that the Flanker must patrol in the interceptor mission. Internal ECM consists of IFF, RWR, DDS, and DJM. There is no evidence to suggest that the Su27 carries an internal AJM. The distinctive "tail stinger" in fact carries fuel and a breaking parachute.
It is also interesting to note that the Su-27, like most other Soviet fighters, has been designed to utilize specific types of air-to-air missiles, in this case the AA-10, AA-11, and AA-8. The original prototype of the Su-27 was designated Flanker-A. The revised prototype and subsequent operational aircraft have been designated Flanker-B.
There exists a two-seat trainer version designated Su-27UB that retains the radar and full combat capability of the Flanker- B. The carrier-borne variant is designated Flanker-B2 and incorporates folding wings, strengthened landing gear, an arrestor hook, and moveable canard surfaces that reportedly reduce landing speed. It will also be capable of in-flight refueling with a retractable probe and the ability to carry a large "buddy" refueling tank with hose-and-drogue hookup on the centerline station. This aircraft will constitute the primary fighter/interceptor strength of the Soviet carrier air wings.
While the Flanker has not yet been exported, Finland has expressed an interest in evaluating it as a replacement for their aging fleet of MG-21 Fishbeds. India is, as always, a potential customer for Soviet aircraft. Sukhoi's claim that the Su-27 costs only 10% more than the smaller and less capable MG-29 is probably a big factor in this interest.
At the 1989 Paris Air Show, and in air shows since then, the Su-27 has thrilled spectators with its impressive aerobatic displays, including the new "cobra" maneuver. The aircraft is pitched up from level flight at 300 mph to an attitude of 120 degrees above the horizontal. It flies this way, tail forward, momentarily before recovering, nose down, with its speed reduced to approximately 100 mph. As incredible as this maneuver sounds, keep in mind that it has only been executed by very experienced test pilots and only after switching off the angleof-attack limiters that would normally govern the aircraft's flight restrictions
Note: Damage Control Correction
Issue #9: SU-27 Revised Data Card -- Add IR UNCAGE to Technology. It was accidently left off.
Air Superiority Data Cards
Two Beasts Su-27 Flanker and IAF Kurnass F-4/2000
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© Copyright 1990 by J.D. Webster
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