Su-37 "Super Flanker"

Su-37 Super Flanker is a super-maneuverable thrust vectoring fighter with the factory designation T-10M-11 derived from an Su-35 prototype. The last Su-35 prototype - number 711 - was fitted with Lyulka Saturn AL-31FU engines that incorporate two-dimensional thrust-vectoring (TVC) nozzles. Externally similar to the Su-35 - apart from the nozzles - the Su-37 has a side-stick controller and has demonstrated some amazing manoeuvres, including a complete 360deg Cobra - known as a Kulbit.

This single-seat and/or two-seat multi-role combat aircraft was first shown in model form at 1991 trade shows. Some wind tunnel tests completed as the aircraft entered the basic design stage in 1992, with foreign partners being sought for development. Unlike the other twin-engine Su-27 derivatives, the Su-37 concept originally featured a single Soyuz/Tumansky turbofan engine rated at 180 kN (40500 lb st) thrust with afterburning. What finally emerged from the design process was a super maneuverable version of the Su-35 with a pair of AL-37FU afterburning turbofans with axisymmetric, steerable nozzles and thrust vector control (TVC). When the Su-37 was shown at Farnbrough in 1996 it stole the show, performing an astounding aerobatic display.

The Su-37 represents a new level of capability compared with the Su-27 and Su-35. The Su-37 test aircraft made its maiden flight in April 1996 from the Zhukovsky flight testing center near Moscow. This impressive single-seat all-weather counter-air fighter and ground attack aircraft, derived from the SU-27, has an updated airframe containing a high proportion of carbon-fiber and Al-Li alloy. The engines, avionics and armaments are also improvements on those originally installed in the SU-27. The AL-37FU engines are configured for thrust vector control, with the axisymmetric steerable thrust vector control nozzle is fixed on a circular turning unit. The steel nozzle in the experimental engines is replaced in production engines by titanium units to reduce the weight of the nozzle. The nozzle only moves in the pitch axis, and the nozzles on the two engines can deflect together or differentially to achieve the desired thrust vector for a particular maneuver.

The Su-37 has a variety of other innovative equipment such as a radar configured for simultaneous surveillance of airspace and the ground and a high-precision laser-inertial/satellite navigation system. The all-weather digital multi-mode phased array radar operates in either air and ground surveillance modes or in both modes simultaneously. Ground surveillance modes include mapping (with Doppler beam sharpening), search-and-track of moving targets, synthetic aperture radar and terrain avoidance. The Su-37 is also equipped with a rearward facing radar in the tail stinger area of the fuselage. The Su-37 features fly-by-wire and relaxed static instability, which along with 2D thrust vectoring give the aircraft tremendous agility. In the 1980’s General Designer Mikhail P. Simonov insisted that the Su-37 be equipped with axisymmetric vectoring nozzles instead of the 2D vectoring nozzles. When Sukhoi did research and testing for each configuration, they found that the 2D nozzle suffered from serious technological problems. However, in the end, the 2D Su-37 was produced, of which no major problems were seen to jeopardize the Su-37’s operational performance.

It incorporates state of the art ECM in wing-tip pods, allowing improved survivability in electronic warfare environments. The Su-37 can carry air-to-air and air-to-surface weapons on 12 stations. The number of missiles and bombs carried can be increased to 14 with the use of multi-payload racks. The military arsenal had become more diverse in comparison with the Su-27. The new aircraft could use not only unguided missiles and free-falling bombs, but also guided air-to-surface missiles, including anti-ship ones.

However, the main "weapon" of the Su-37 was its super maneuverability. For the first time, he demonstrated the ability to reach ultra-large angles of attack and near-zero speeds. Thanks to the automation of all controls, the fighter could "independently" exit the tailspin.

The first demonstration of the Su-37 to the general public took place, as already mentioned, in 1996 at the air show in Le Bourget. However, everything was about to fail. For a number of reasons, the aircraft with tail number 711 arrived in Paris only on the sixth day of the exhibition and without permits. But many delegations postponed their departure just to see the new Russian fighter. Hero of Russia test pilot Evgeny Frolov desperately tried to get the right to speak. Only the intervention of Russian Deputy Prime Minister Jacob Urinson and Russian Ambassador to France Yuri Ryzhov helped.

But in the sky could not do without "adventures". The first three flights went well, and during the fourth it was not possible to remove the chassis. Then the pilot performed a short aerobatics with a “cobra” with the landing gear extended and landed the Su-37. Fortunately, there were no breakdowns. It was just that the emergency release valve handle was in the wrong position. Having eliminated the cause of the incident, the pilot again ascended to the sky and completed the full program. This incident did not overshadow the speech. The audience was delighted.

At the September 1996 Farnborough Air Show, Sukhoy’s SU-37 astounded international observers with maneuverability previously unseen in a combat aircraft. Evgeny Frolov again impressed foreign experts, this time in Farnborough. So began the triumphal march of the Su-37 at world air shows. On a new plane, the pilot first demonstrated a somersault aerobatics (360-degree turn in the symmetry plane). In other words, a dead loop of small radius, performed at low speed. Later it received the name "Frolova Chakra". However, the old figures performed by the Su-37 were like new. For example, when performing the "cobra" he went to an angle of attack of more than 150 degrees and is in this position for 3-4 seconds. After that, the pilot could take the most advantageous position for him in aerial combat. Many tricks were subject to the fighter: forced (less than 10 seconds) combat turn, vertical turn, coup with loss of height up to 300-400 meters. Perhaps for this he received the respectful nickname "Terminator" from journalists. The thrust-vectoring SU-27 variant stole show headlines with flight demonstrations widely described in the aviation press as “spectacular.” One air show reporter opined that the SU-37 shows that the Russian aviation industry “is still alive.”

The Su-37's astounding maneuvers included the "Super Cobra", demonstrated for the first time. In this move, the aircraft enters with a speed of 400 kmh and is pulled through to an alpha of 135 degrees, then recovered to the vertical and held in place for 4-6 seconds. The nose is then allowed to fall to the horizontal position, emerging at 150kmh with no loss of height. Another used the thrust vectoring to flip the Su-37 onto it's back (a full 180 degress), and then to rotate it upright and continue in the opposite direction. The most impressive maneuver was the kulbit (somersault). With an entry speed of 350 kmh the aircraft flipped onto it's back, a 180 degree flip facing the opposite direction, inverted and practically stationary. After 'pausing', thrust vectoring completes the kulbit (a 360 deg somersault) with a nose down angle of 30 deg and an exit speed of 60 km/h.

Sukhoi used payments earned in the sale of an Su-27 license to China to finance the Su-37 development. Russia's Air Force did not order any Su-37s. Sukhoi studyied the possibility of developing a two-seat version of the Su-37 with enhanced strike capabilities.

Paradoxically, the only drawback of the Su-37 was its uniqueness. The plane existed in one instance. December 19, 2002 a fighter crashed near Moscow. Fortunately, test pilot Yuri Vashchuk managed to eject. But the Su-37 project crashed. He did not continue. Why? There are different opinions on this. Some believe that the aircraft industry was going through difficult times at that time, and there was no money for the reconstruction of the aircraft.

Others are convinced that the Su-37 was not ready for mass production. There was a flying laboratory, which, for reasons of prestige, was presented as the newest fighter. And she fulfilled her role. Engines with UVT were run in on the Su-37, gained valuable experience, which was useful when creating other super-maneuverable fighters.