Picard
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Sukhoi Su-37 Terminator – History and War (wordpress.com)
Su-37 was an intended successor of Su-27, itself a first aircraft of the fourth generation available to Russian air forces. When first fighter aircraft of the fourth generation had appeared, they were characterized by greater agility, improved weapons systems and avionics. Major members of this group are F-15, F-16, F/A-18, MiG-29 and Su-27. On the contrary, aircraft of fifth generation are characterized by vector thrust and reduced radar signature.
The Sukhoi Design Bureau had started research on thrust vectoring in 1983., working on an upgrade of Su-27, designated Su-27M. This process included a study of axysimmetrical thrust vectoring nozzles, and by the late 1980s nozzles were being tested in flight. In 1988., test flights for Su-27M revealed that the pilots failed to maintain active control of the aircraft at high angles of attack, since control surfaces were not effective at low speeds. Thus, thrust vectoring engines were installed on T10M-11, a Su-27 that was also being used as a radar test bed. Aircraft was temporarily fitted with AL-31FP engines, an AL-31F engine with a thrust vectoring nozzle. The aircraft was rolled out in may, and two months later, AL-31FP engines were replaced with AL-37FUs.
First flight of the Su-37 prototype was carried out on 2nd April 1996., with the aircraft being piloted by Yevgeni Frolov, one of best Russian test pilots. Five months later, aircraft appeared at Farnborough ’96, during which it demonstrated the “Super Cobra” maneuver for the first time. Maneuver is initiated by horizontal flight at 400 kph, after which aircraft increases angle of attack to 135° before reducing it to 90° and keeping that angle for 4 – 6 seconds. Afterwards, pilot ends the maneuver by dropping aircraft’s nose and keeps flying at 150 km/h without losing altitude.
Su-37, likely during Kulbit maneuvre
Most impressive maneuver in Su-37s repertoire was kulbit (loop). Aircraft entered the maneuver by flying horizontally at speed of 350 kph, then increased the angle of attack to 180°, turning itself on the back, and then by using vectored thrust it finished the loop. At the exit from the loop, aircraft was in a nose-down position of 30° and at speed of 60 kph. Such maneuver is only possible through thrust vectoring.
Eventually, however, the engines had to be replaced with non-thrust vectoring variants due to expiration of service life. Foreign avionics were also replaced with indigenous designs, and test flights were resumed in October 2000. The aircraft crashed in December 2002 due to a structural failure caused by the repeated stresses during six years of testing. It never entered production, and instead lessons and systems developed for Su-37 were applied to bureau’s other aircraft, and modernized Su-35 made its first flight in 2008.
Vectored Thrust
Most aircraft have a fixed direction of exhaust, which means that changes in direction of flight and aircraft’s attitude are achieved solely by aerodynamic surfaces. These include ailerons, rudders and elevators, which rotate the aircraft around the x (longitudinal), z (vertical) and y (transverse) axis, respectively. With aircraft utilizing vector thrust, direction of the thrusting force can be can be deflected from the longitudinal axis, thus creating additional moment aiding in rotation around the axis at the expense of the forward thrust vector. As a result, aircraft using vectored thrust can fly at far greater angles of attack than conventional aircraft, allowing them to perform maneuvers in a much smaller area and at much lower speeds.
Each engine provides 83.36kN thrust and 142kN with the afterburner and is steerable from -15° to +15° along the vertical plane. Thrust vector control was fully integrated into the digital flight control system, but could also be operated manually by the pilot. Nozzles could be deflected both synchroniously and differentially, depending on maneuver. The nozzle is connected to the annular swivel and can be moved in the pitch plane by two pairs of hydraulic jacks.
TVC nozzles
After thrust vectoring engines were removed, they were replaced non-TVC variants. At the same time, Su-37 was given an updated Flight Control System. New FCS included the controls for differential impulse, allowing one engine to reduce thrust and thus turn aircraft to side. Due to this and other changes, it was able to keep most of its impressive acrobatic ability even without thrust vectoring. Current MiG-35 utilizes this system, using assymetric thrust, lower fences on LEX and air brake to simulate thrust vectoring and thus achieve full maneuverability of a TVC-equipped aircraft without using thrust vectoring.
Avionics and Weapons
While outwardly similar to canard-equipped Su-27M, Su-37 had far more advanced avionics. Analogue flight control system was replaced by a digital fly-by-wire FCS, which was directly linked to the thrust vectoring control system. Cockpit had LCDs in place of cathod ray tube monitors, and central stick had been replaced with a side stick. Aircraft’s weapons control systems had also been improved, as they included an N011M Bars pulse-doppler phased array radar.
Radar N-011M used by the aircraft was multifunctional and resistant to jamming. Maximum range was 400 kilometers against airborne targets and 200 kilometers against ground targets. It could track and attack air and ground targets simultaneously. In air-to-air mode, radar was capable of simultaneously tracking 20 aerial targets, and attacking eight of them, compared to 15 and six, respectively, for Su-27s N011. Aircraft also had a self-defense N012 tail radar with range of 4 km, allowing it to attack targets in the rear quadrant by using short-range R-73E missile. Considerable improvement had been made to the cockpit layout, which included heads-up display and four Sextant Avionique multi-function colour liquid crystal displays.
Su-37
Su-37 also had a single 30 mm GSh-301 cannon, with maximum rate of fire of 1500 rpm and a total of 150 rounds in magazine. Main close-range weapon were short-range R-73E IR missiles, with range of 300 meters to 30 km. This missile is equipped with 3D thrust vectoring, allowing it very high agility and ability to engage targets 60 degrees off the axis. For combat at middle range, Su-37 utilized R-27 and R-77 missiles, which could be either radar- or IR- -guided and had a range of up to 150 kilometers.
For attacking targets at large distances, Su-37 could have used Ks-172 missile, with maximum range of 400 kilometers. This six meters long missile had active radar guidance. It could also have carried a variety of missiles for attacking ground or naval targets, such as Kh-41 Moscit, 10 meters long and sporting a 320 kg warhead.
In total, Su-37 had the ability to carry up to 14 missiles or up to 8 000 kg of ordnance. The 12 external hardpoints were able to carry air-to-air missiles, air-to-surface missiles, bombs, rockets, and an ECM pod.
Basic Specifications
Length: 22,1 m
Wing span: 14,7 m
Height: 6,32 m
Weight:
Su-37 was an intended successor of Su-27, itself a first aircraft of the fourth generation available to Russian air forces. When first fighter aircraft of the fourth generation had appeared, they were characterized by greater agility, improved weapons systems and avionics. Major members of this group are F-15, F-16, F/A-18, MiG-29 and Su-27. On the contrary, aircraft of fifth generation are characterized by vector thrust and reduced radar signature.
The Sukhoi Design Bureau had started research on thrust vectoring in 1983., working on an upgrade of Su-27, designated Su-27M. This process included a study of axysimmetrical thrust vectoring nozzles, and by the late 1980s nozzles were being tested in flight. In 1988., test flights for Su-27M revealed that the pilots failed to maintain active control of the aircraft at high angles of attack, since control surfaces were not effective at low speeds. Thus, thrust vectoring engines were installed on T10M-11, a Su-27 that was also being used as a radar test bed. Aircraft was temporarily fitted with AL-31FP engines, an AL-31F engine with a thrust vectoring nozzle. The aircraft was rolled out in may, and two months later, AL-31FP engines were replaced with AL-37FUs.
First flight of the Su-37 prototype was carried out on 2nd April 1996., with the aircraft being piloted by Yevgeni Frolov, one of best Russian test pilots. Five months later, aircraft appeared at Farnborough ’96, during which it demonstrated the “Super Cobra” maneuver for the first time. Maneuver is initiated by horizontal flight at 400 kph, after which aircraft increases angle of attack to 135° before reducing it to 90° and keeping that angle for 4 – 6 seconds. Afterwards, pilot ends the maneuver by dropping aircraft’s nose and keeps flying at 150 km/h without losing altitude.
Most impressive maneuver in Su-37s repertoire was kulbit (loop). Aircraft entered the maneuver by flying horizontally at speed of 350 kph, then increased the angle of attack to 180°, turning itself on the back, and then by using vectored thrust it finished the loop. At the exit from the loop, aircraft was in a nose-down position of 30° and at speed of 60 kph. Such maneuver is only possible through thrust vectoring.
Eventually, however, the engines had to be replaced with non-thrust vectoring variants due to expiration of service life. Foreign avionics were also replaced with indigenous designs, and test flights were resumed in October 2000. The aircraft crashed in December 2002 due to a structural failure caused by the repeated stresses during six years of testing. It never entered production, and instead lessons and systems developed for Su-37 were applied to bureau’s other aircraft, and modernized Su-35 made its first flight in 2008.
Vectored Thrust
Most aircraft have a fixed direction of exhaust, which means that changes in direction of flight and aircraft’s attitude are achieved solely by aerodynamic surfaces. These include ailerons, rudders and elevators, which rotate the aircraft around the x (longitudinal), z (vertical) and y (transverse) axis, respectively. With aircraft utilizing vector thrust, direction of the thrusting force can be can be deflected from the longitudinal axis, thus creating additional moment aiding in rotation around the axis at the expense of the forward thrust vector. As a result, aircraft using vectored thrust can fly at far greater angles of attack than conventional aircraft, allowing them to perform maneuvers in a much smaller area and at much lower speeds.
Each engine provides 83.36kN thrust and 142kN with the afterburner and is steerable from -15° to +15° along the vertical plane. Thrust vector control was fully integrated into the digital flight control system, but could also be operated manually by the pilot. Nozzles could be deflected both synchroniously and differentially, depending on maneuver. The nozzle is connected to the annular swivel and can be moved in the pitch plane by two pairs of hydraulic jacks.
After thrust vectoring engines were removed, they were replaced non-TVC variants. At the same time, Su-37 was given an updated Flight Control System. New FCS included the controls for differential impulse, allowing one engine to reduce thrust and thus turn aircraft to side. Due to this and other changes, it was able to keep most of its impressive acrobatic ability even without thrust vectoring. Current MiG-35 utilizes this system, using assymetric thrust, lower fences on LEX and air brake to simulate thrust vectoring and thus achieve full maneuverability of a TVC-equipped aircraft without using thrust vectoring.
Avionics and Weapons
While outwardly similar to canard-equipped Su-27M, Su-37 had far more advanced avionics. Analogue flight control system was replaced by a digital fly-by-wire FCS, which was directly linked to the thrust vectoring control system. Cockpit had LCDs in place of cathod ray tube monitors, and central stick had been replaced with a side stick. Aircraft’s weapons control systems had also been improved, as they included an N011M Bars pulse-doppler phased array radar.
Radar N-011M used by the aircraft was multifunctional and resistant to jamming. Maximum range was 400 kilometers against airborne targets and 200 kilometers against ground targets. It could track and attack air and ground targets simultaneously. In air-to-air mode, radar was capable of simultaneously tracking 20 aerial targets, and attacking eight of them, compared to 15 and six, respectively, for Su-27s N011. Aircraft also had a self-defense N012 tail radar with range of 4 km, allowing it to attack targets in the rear quadrant by using short-range R-73E missile. Considerable improvement had been made to the cockpit layout, which included heads-up display and four Sextant Avionique multi-function colour liquid crystal displays.
Su-37 also had a single 30 mm GSh-301 cannon, with maximum rate of fire of 1500 rpm and a total of 150 rounds in magazine. Main close-range weapon were short-range R-73E IR missiles, with range of 300 meters to 30 km. This missile is equipped with 3D thrust vectoring, allowing it very high agility and ability to engage targets 60 degrees off the axis. For combat at middle range, Su-37 utilized R-27 and R-77 missiles, which could be either radar- or IR- -guided and had a range of up to 150 kilometers.
For attacking targets at large distances, Su-37 could have used Ks-172 missile, with maximum range of 400 kilometers. This six meters long missile had active radar guidance. It could also have carried a variety of missiles for attacking ground or naval targets, such as Kh-41 Moscit, 10 meters long and sporting a 320 kg warhead.
In total, Su-37 had the ability to carry up to 14 missiles or up to 8 000 kg of ordnance. The 12 external hardpoints were able to carry air-to-air missiles, air-to-surface missiles, bombs, rockets, and an ECM pod.
Basic Specifications
Length: 22,1 m
Wing span: 14,7 m
Height: 6,32 m
Weight:
- Empty: 18 500 kg
- Air combat takeoff: 26 000 kg
- Maximum takeoff: 34 000 kg
- Maximum speed at altitude: 2 400 kph
- Maximum speed at sea level: 1 400 kph
- Service ceilling: 18 000 m
- Range on internal fuel: 3 300 km
- G limit: +9
- 1 x 30 mm GSh-30-1 internal cannon with 150 rounds
- 12 hardpoints with capacity of 8 000 kg of ordnance
- N-011M Bars passive electronically scanned array radar
- N012 self-defence radar
- OLS-35 infrared search and track system
