The Sukhoi Su-47 Berkut (Russian: Су-47 Беркут - Golden Eagle) (NATO reporting name Firkin), also designated S-32 and S-37 during initial development, is an experimental supersonic jet fighter developed by Sukhoi Aviation Corporation. A distinguishing feature of the aircraft is its forward-swept wing, similar to that of the Tsybin's LL-3.. The sole aircraft produced is an advanced technology demonstrator prototype and manufacture of a planned second flying prototype is under question due to recent MIG developments of 5th generation Jet fighters.Originally known as the S-37, Sukhoi redesignated its advanced test aircraft as the Su-47 in 2002. Officially nicknamed Berkut (Golden Eagle), the Su-47 was originally built as Russia's principal testbed for composite materials and sophisticated fly-by-wire control systems. The aircraft makes use of forward-swept wings allowing superb maneuverability and operation at angles of attack up to 45° or more.
TsAGI has long been aware of the advantages of forward-swept wings, with research including the development of the Tsibin LL and study of the captured Junkers Ju 287 in the 1940s. Forward-swept wings yield a higher maximum lift coefficient, reduced bending moments, and delayed stall when compared to more traditional wing shapes. At high angles of attack, the wing tips remain unstalled allowing the aircraft to retain aileron control. Unfortunately, forward sweep also induces twisting (divergence) strong enough to rip the wings off an aircraft built of conventional materials. Only recently have composite materials made the design of aircraft with forward-swept wings feasible.
The project was launched in 1983 on order from the Soviet Air Force. But when the USSR dissolved, funding was frozen and development continued only through funding by Sukhoi. Like its US counterpart, theGrumman X-29, the Su-47 is primarily a technology demonstrator for future Russian fighters. However, Sukhoi is now attempting to market the Su-47 to the Russian military and foreign customers as a production fighter in its own right.
The Su-47 is of similar dimensions to previous large Sukhoi fighters, such as the Su-35. To reduce development costs, the Su-47 borrowed the forward fuselage, vertical tails, and landing gear of the Su-27 family. Nonetheless, the aircraft includes reduced radar signature features (including radar absorbent materials),an internal weapons bay, and space set aside for an advanced radar. Though similar in overall concept to the American X-29 research aircraft of the 1980s, the Su-47 is about twice the size and far closer to an actual combat aircraft than the US design.
To solve the problem of wing-twisting, the Su-47 makes use of composite materials carefully tailored to resist twisting while still allowing the wing to bend for improved aerodynamic behavior. Due to its comparatively large wingspan the Su-47 is to be equipped with folding wings in order to fit inside Russian hangars.
Like its immediate predecessor, the Su-37, the Su-47 is of tandem-triplane layout, with canards ahead of wings and tailplanes. Interestingly, the Su-47 has two tailbooms of unequal length outboard of the exhaust nozzles. The shorter boom, on the left-hand side, houses rear-facing radar, while the longer boom houses a brake parachute.
The Su-47 has extremely high agility at subsonic speeds, enabling the aircraft to alter its angle of attack and its flight path very quickly while retaining maneuverability in supersonic flight. The Su-47 has a maximum speed of Mach 1.6 at high altitudes and a 9g capability.
Maximum turn rates, and the upper and lower limits on airspeed for weapon launch, are important criteria in terms of combat superiority. The Su-47 aircraft has very high levels of maneuverability with maintained stability and controllability at extreme angles of attack. Maximum turn rates are important in close combat and also at medium and long range, when the mission may involve engaging consecutive targets in different sectors of the airspace. A high turn rate of the Su-47 allows the pilot to turn the fighter aircraft quickly towards the next target to initiate the weapon launch. Like most other fighters with fly by wire controls, the Su-47 achieves some of its high maneuverability through relaxed stability.
Specifications (Su-47)
General characteristics
- Crew: 1
- Length: 22.6 m (74 ft 2 in)
- Wingspan: 15.16 m to 16.7 m (49 ft 9 in to 54 ft 9 in)
- Height: 6.3 m (20 ft 8 in)
- Wing area: 61.87 m² (666 ft²)
- Empty weight: 16,375 kg (36,100 lbs)
- Loaded weight: 25,000 kg (55,115 lb)
- Max takeoff weight: 35,000 kg (77,162 lbs)
- Powerplant: 2× Lyulka AL-37FU(planned) Flying prototypes used 2 Aviadvigatel D-30F6 afterburning, thrust-vectoring (in PFU modification) turbofans with digital control
- Dry thrust: 83.4 kN (18,700 lbf) each
- Thrust with afterburner: 142.2 kN (32,000 lbf) each
- Thrust vectoring: ±20° at 30° per second in pitch and yaw
Performance
- Maximum speed: Mach 1.6 (Achieved in test flights ) (1,717 km/h, 1,066 mph),projected 2710 km/h
* At sea level: Mach 1.14 (1,400 km/h, 870 mph) - Cruise speed: projected 1,800 km/h on dry thrust, 2650 km/h on full thrust
- Range: 3,300 km (2,050 mi)
- Service ceiling: 18,000 m (59,050 ft)
- Rate of climb: 233 m/s (46,200 ft/min)
- Wing loading: 360 kg/m² (79.4 lb/ft²)
- Thrust/weight: 1.18 when fully loaded,1.15 when empty
Armament
Number of hardpoints: 14: 2 wingtip, 6-8 under wing, 6-4 conformal under fuselage
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