Developments from the Su-27 "Flanker" Design...
- The Su-33 'Flanker-D' is a Fleet Defense Interceptor that was developed from the Su-27 design for use on aircraft carriers. Main differences include a tail hook and canards. Given the purpose of this interceptor, one would say that its closest counterpart is the American F-14 Tomcat, whereas the MiG-29K 'Fulcrum-D' would be analogous to the F/A-18 Hornet.
- The Su-30 is a two-seat, dual-role fighter for all-weather, air-to-air and deep interdiction missions.
- Further versions include the Su-34 'Fullback' strike variant and the Su-35 'Flanker-E' improved air defense fighter.
In 1969, the Soviet Union learned of the United States Air Force's selection of McDonnell Douglas to produce the Fighter Experimental design (which was to become the F-15 Eagle). In response to that upcoming threat, the Soviets instituted the PFI (perspektivnyi frontovoy istrebitel, Advanced Frontline Fighter) program for an aircraft that could match the new American fighter on its own terms.
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), just as the F-15 program spawned the Lightweight Fighter (LWF) program that produced the F-16 and YF-17 Cobra. Sukhoi OKB was assigned the TPFI program.
Design...
The Su-27's basic design is aerodynamically similar to the MiG-29, but it is substantially larger. It is a very large aircraft, and to minimize its weight its structure has a high percentage of titanium (about 30%, more than any of its contemporaries). No composite materials were used. The swept wing blends into the fuselage at the leading edge extensions and is essentially a delta, although the tips are cropped for wingtip missile rails or ECM pods. The Su-27 is not a true delta, however, because it retains conventional tailplanes, with two vertical tailfins outboard of the engines, supplemented by twofold-down ventral fins for additional lateral stability.
The Su-27's Lyulka AL-31F turbofan engines are widely spaced, both for safety reasons and to ensure uninterrupted airflow through the intakes. The space between the engines also provides additional lift, reducing wing loading. Movable guide vanes in the intakes allow Mach 2+ speeds, and help to maintain engine airflow at high alpha. A mesh screen over each intake prevents debris from being drawn into the engines during take-off.
The Su-27 had the Soviet Union's first operational fly-by-wire control system, developed based on Sukhoi OKB's experience in the Sukhoi T-4 bomber project. Combined with relatively low wing loading and powerful basic flight controls, it makes for an exceptionally agile aircraft, controllable even at very low speeds and high angles of attack. In airshows the aircraft has demonstrated its maneuverability with a Cobra (Pugachev's Cobra) or dynamic deceleration - briefly sustained level flight at a 120° angle of attack. Thrust vectoring has also been tested (and is incorporated on later Su-30MKI and Su-37 models), allowing the fighter to perform hard turns with almost no radius, incorporate vertical somersaults into level motion and limited nose-up hovering.
The naval version of the 'Flanker,' the Su-27K (or Su-33), incorporates canards for additional lift, reducing take-off distances (important because the aircraft carrier Admiral Kuznetsov has no catapults). These canards have also been incorporated in some Su-30s, the Su-35, and the Su-37.
In addition to its considerable agility, the Su-27 uses its substantial internal volume for a large internal fuel capacity. In an overload configuration for maximum range, it can carry 9,400 kg (20,700 lb) of internal fuel, although its maneuverability with that load is limited, and normal load is 5,270 kg (11,620 lb).
The Su-27 is armed with a single Gryazev-Shipunov GSh-30-1 30 mm cannon in the starboard wingroot, and has up to 10 hardpoints for missiles and other weapons. Its standard missile armament for air-to-air combat is a mixture of Vympel R-73 (AA-11 Archer), Vympel R-27 (AA-10 'Alamo') weapons, the latter including extended range and IR guided models. More advanced Flanker variants (such as Su-30, -35, -37) may also carry Vympel R-77 (AA-12 Adder) missiles.
The first of the N001 series radar, the Tikhomirov (NIIR) N001 (NATO 'Slot Back'), is a pulse-Doppler set with track-while-scan capability, but its processor is relatively primitive, making it vulnerable to false alarms and blind spots, as well as being more difficult to use. During the years, under the chief designer of N001 radar, Professor Viktor Konstantinovitch Grishin, the N001 radar has been upgraded many times, resulting in derivatives including N001V, N001VE, N001VEP, all of which are in service, including those exported Flankers. Professor V.K. Grishin was the chief designer of Zalson S-800 passive phased array radar on MiG-31, and the expertise would later contribute to the design of the replacement phased array radars for the N001 series.It was apparent that there was not much room for any significant improvement anymore for the N001 series radar, and the Su-30 and Su-35/37 aircraft have the vastly superior Tikhomirov (NIIR) 'Bars' (Panther) N011M with a passive electronically scanned array, improving range, multiple target capability, and sensitivity. The Bars (Panther) radar is scheduled to be replaced by an even more capable successor, Irbis (Snow leopard)-E phased array radar in the near future. Tikhomirov (NIIR)'s competitor, Phazotron (NIIP) also offered similar radar with passive electronically scanned array.
The Su-27 has an infrared search and track (IRST) system in the nose just forward of the cockpit, which also incorporates a laser rangefinder. This system can be slaved to the radar, or used independently for "stealthy" attacks with infrared missiles (such as the R-73 and R-27T/ET). It also controls the cannon, providing greater accuracy than a radar sighting mode.
While the Su-27 and its immediate descendants (Su-35 and -37) have outstanding maneuverability and performance, the airframe design lacks stealth features, so the radar cross section (RCS) is large.
Combat Service...
The Su-27 has seen limited action since it first entered service. Ethiopian Su-27s reportedly shot down two, three or five Eritrean MiG-29s; the first on February 25th, 1999 and the second on February 26th, 1999. and the third on May 16th, 2000. The Su-27s were also used in CAP (Combat Air Patrol) missions, suppression of air defense, and providing escort for fighters on bombing and reconnaissance missions.
In Angolan service, one Su-27 was shot down by a SA-14 MANPADS fired by UNITA forces on November 19th, 2000. Angolan Su-27 entered service in mid 2000.
Specifications...
Data from Gordon and Davidson 2006, KNAAPO Su-27SK page, Sukhoi Su-27SK page
General characteristics
- Crew: 1 or 2
- Length: 21.9 m (72 ft)
- Wingspan: 14.7 m (48 ft 3 in)
- Height: 5.92 m (19 ft 6 in)
- Wing area: 62 m² (667 ft²)
- Empty weight: 16,380 kg (36,100 lb)
- Loaded weight: 23,430 kg (51,650 lb)
- Max takeoff weight: 30,450 kg (67,100 lb)
- Powerplant: 2× Saturn/Lyulka AL-31F turbofans
Dry thrust: 7,670 kgf (75.22 kN, 16,910 lbf) each
Thrust with afterburner: 12,500 kgf (122.6 kN, 27,560 lbf) each
- Leading edge sweep: 42°
Performance
- Maximum speed: Mach 2.35 (2,500 km/h, 1,550 mph) at altitude
- Range: 3,530 km (2,070 mi) at altitude; (1,340 km / 800 mi at sea level)
- Service ceiling: 18,500 m (62,523 ft)
- Rate of climb: 300 m/s (64,000 ft/min)
- Wing loading: 371 kg/m² (76 lb/ft²)
- Thrust/weight: 1.09
Armament
- 1 × 30 mm GSh-30-1 cannon with 150 rounds
- 8,000 kg (17,600 lb) on 10 external pylons
- Up to 6 × medium-range AA missiles R-27, 2 × short-range heat-seeking AA missiles R-73
- Upgraded Su-27SM is capable of using R-77 instead of R-27
Su-27S armament
- 30 mm GSH-30 Cannon, 150 rounds
- 6 × R-27R, R-27ER, R-27T, R-27ET
- 4 × R-73E
- FAB-250
- FAB-500
- B-8
- B-13
- S-24
- S-25
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