What is Kulbit maneuver ?

Su-37KulbitThe Kulbit, also known as the Frolov chakra maneuver is an aerial maneuver developed by Russian pilots in which the aircraft performs an extremely tight loop, often not much wider than the length of the aircraft itself. It is an example of post-stall maneuvering, a type of super-maneuverability. Like most post-stall maneuvers, it demonstrates pitch control outside of the normal flight envelope wherein pitch control is made possible by having aerodynamic flow over the aircraft’s elevators or stabilators. The name Kulbit is derived from the Russian Кульбит, meaning Somersault . The alternate name, Frolov’s Chakra, refers to Russian test pilot Yevgeni Frolov, the pilot who first carried out the maneuver, while Chakra is a yogic term, meaning Vortex or Whirlpool .The Kulbit drastically decreases the aircraft’s speed and could theoretically be used to cause a pursuing aircraft to overshoot its target. The maneuver is closely related to the famous Pugachev’s Cobra maneuver, but the Kulbit completes the loop that the Cobra almost immediately cuts off.

The following aircraft are currently known to be able to execute the Kulbit :

  • Mikoyan MiG-29OVT Fulcrum ( Russia )
  • Sukhoi Su-35 Flanker-E ( Russia )
  • Sukhoi Su-37 Flanker – Terminator ( Russia )
  • Sukhoi Su-30MKI/SM Flanker ( Russia )
  • Sukhoi Su-47 Berkut ( Russia )
  • Lockheed Martin F-22 Raptor ( USA )
  • Sukhoi PAK-FA T-50 ( Russia )

retournement mig29

source: en.wikipedia.org

Su-37 Flanker F – Terminator

Multi-Role Export Flanker

The designation Su-37 was first used to market a truly multi-role version of the Su-35 (Su-27M) to the United Arab Emirates (UAE) air force. The Su-37MR (MR for multi-role) that was offered would have French-built instrumentation equipment and a number of changes in the avionics. Sukhoi Design Bureau and KnAAPO export company selected the series produced T10M-11 (Su-27M pre-production test aircraft) for conversion, which had already been testing the multi-mode N011M phased array radar. However the UAE preferred the Mirage 2000-9 and it was decided to use the T10M-11 as flying test-bed for the engine thrust vector control (TVC) system. The Su-37 designation was retained.

Su-37 Flanker F - Terminator

Su-37 Flanker F – Terminator

Introducing Thrust Vector Control

The TVC system enables the aircraft to direct its thrust produced by the AL-31F engines in a different angle than the flight path on the vertical axis. In high angles of attack, normally an aircraft would stall and the pilot would lose control because of the disrupted airflow over the control surfaces. Also at very low air speeds, the control surfaces no longer function effectively. With TVC the aircraft can still be controlled under these circumstances by using the engines thrust instead of the airflow.

The new Su-37 made its first flight fitted with the TVC engines on 2 April 1996 by Sukhoi’s test pilot Yevgeny Frolov. The aircraft was nicknamed Terminator.


The Su-37’s TVC system is integrated into the aircraft’s fly-by-wire system, giving the aircraft controllability at beyond-critical angles of attack and near-zero speeds. The Su-37 was able of performing aerobatics unmatched by any contemporary fighter. Examples include vertical somersault while retaining the flight path (Frolov’s chakra), forced tight radius turns, controlled spin. This super-maneuverability would give the Su-37 an edge in dogfights with other aircraft. It also stunned the public at the Farnborough airshow in September 1996, Le Bourget in June 1997 and MAKS in August of 1997.

Su-37 and F-16

Su-37 near F-16

The Su-37 engine nozzles swiveled only vertically (2D vectoring). Lyulka-Saturn further developed the vectoring nozzle which resulted in the AL-31FP thrust vector control engines capable of moving in both vertical and horizontal axes (3D vectoring). The AL-31FP engine was offered to foreign customers on more advanced developments of the Su-30MK such as the Su-30MKI of the Indian Air Force and as an option for customized versions of the earlier Su-35 ‘Super’ Flanker.

Sukhoi Su-37 multirole fighter technology demonstrator at Farnborough 1996 airshow

Sukhoi Su-37 multirole fighter technology demonstrator at Farnborough 1996 airshow

End of the Su-37?

The Su-37’s life ended when T10M-11 (serial 711) was lost in a crash on flying a ferry flight in Russia. The aircraft was not fitted with the TVC engines at the time of the crash. No other Su-27Ms have been converted to Su-37 specifications, nor has the Su-37 design entered production. The Su-37 was never an official designation recognized by the Russian Air Force.


The crash of 711 effectively means the end of the Su-37 as we have known since 1996. The possibility remains that the designation Su-37 will be re-used in the future for other Flanker derivatives. Reportedly, localized Su-35 (Su-27BM) air frames for the Russian Air Force will re-use the Su-37 designation.

Su-37 Flanker F

Su-37 Flanker F


General characteristics

  • Crew: 1
  • Length: 21.935 m (72 ft 9 in)
  • Wingspan: 14.698 m (48 ft 3 in)
  • Height: 5.932 m (21 ft 1 in)
  • Wing area: 62.0 m² (667 ft²)
  • Empty weight: 18,500 kg (40,790 lb)
  • Max. takeoff weight: 35,000 kg (77,160 lb)
  • Powerplant: 2 × Lyulka AL-37FU after burning turbofans
    • Dry thrust: 7,600 kgf (74.5 kN, 16,750 lbf) each
    • Thrust with afterburner: 145 kN (32,000 lbf) each


  • Maximum speed: Mach 2.35
  • Range: 3,300 km (1,833 nmi)
  • Service ceiling: 18,000 m (59,055 ft)
  • Maximum g-loading: +10/−3 g


  • 1 × 30 mm GSh-30 cannon with 150 rounds
  • 12 × wing and fuselage stations for up to 8,000 kg (17,636 lb) of ordnance
SU-37 blueprint

click to enlarge

VIdeo about Su-37 Terminator below:

Source: Wikipedia , Milavia

PAK FA (ПАК-ФА T-50) – close photos

Sukhoi company allowed for the first time journalists to see Russian Stealth fighter T-50 (PAK-FA) from close distance at MAKS airshow 2013, Zhukovsky. PAK-FA was in his hangar in Flight Test Center “Suhogo“ (Сухого) Zhukovsky.

Photographed PAK-FA and other two took a part of the Airshow, flying program, showing amazing figures of aerobatics.

Flying tests of T-50, which will enter into service in Russian Army in 2016/2017., held in “Gromov Flight research institute“ (Летно-исследовательского института имени Громова). Four aircraft are included in tests and until end of 2013. joined them fifth jet with number 055.

Development program and many of characteristics are not yet know. Even if most of its technical specs are secret, some details have emerged. T-50 is produced using stealth technology. Super maneuverable fighter is not limited by weather condition or day/night.

The aircraft is a stealth equipped with a front, side and rear AESA radar, as well as L Band radars. It features TVC (Thrust Vectoring Control), a top speed exceeding Mach 2 and super maneuverability. It should carry a wide variety of weapons including air-to-air, air-to-surface and anti-ship missiles.

In other words, it will be Russian answer on American USAF jets F-22 and F-35.

Current contract with Russian Ministry of Defense is about 60 new PAK-FA fighters.

Close PAK-FA Photos: Marina Lystseva

Photos of all 5 prototypes PAK-FA (T-50), numbers from 51 to 55