Su-35 Flanker-E – Russian 4++ generation fighter jet [review]

Suchoi Su-35 is the name for two heavily upgraded versions of the Su-27 (Flanker). These aircraft are sometimes also referred to as Super Flankers.

The first variant was developed in the Soviet Union as early as the 1980s. The version, initially referred to as the Su-27M, had a revised airframe, duck wings, an enlarged radome for the N-011 radar and improved avionics. Financial problems in the 1990s and a lack of export demand contributed to the fact that the first Su-35 design was not developed to series production level despite numerous prototypes. Some machines were used by the Russian aerobatic team “Russkije Witjasi”.

In 2003, Suchoi began to modernize the Su-27 again extensively in order to create an interim solution until the Su-57 was introduced. The duck wings and the air brake of the first Su-35 draft were omitted, the airframe was reinforced and the avionics and radar improved. The more powerful engines have a thrust vector control and should allow supersonic speeds without afterburner. The Russian Air Force ordered a total of 48 machines bearing the type designation Su-35S. Another 50 aircraft were ordered in January 2016.

Based on the operational experience in Syria, among other things, the air inlets of the engines are modified to improve protection against foreign objects. Avionics hardware and software are being adapted to better combat ground targets.

Table of content:
1. History and Development
1.1. First draft
1.2. Second draft Su-35S/BM
2. Construction and technology
2.1. Airframe
2.2. Cockpit
2.3. Avionics
2.4. Engines
3. Versions
4. Technical data
5. Armament
5.1. Armament of the Su-27M/Su-35
5.2. Armament of the Su-35S
6. Commitment
7. Articles

History and Development

First Draft

Even before the Su-27 was put into service, Sukhoi thought about developing an entire family of aircraft from this type. This should consist of a long-range interceptor, an air superiority fighter, a fighter-bomber and a multi-role fighter. Sukhoi called the series 30, with the Su-35 representing the air superiority fighter.

Work on the Su-27M (internal T-10M) began in 1984; on June 28, 1988 the first (T-10M-1) of a total of ten prototypes had its maiden flight. The aircraft now known as the Su-35 (this was the third prototype T-10M-3) had its first public appearance in 1992 at the Farnborough International Airshow.

It turned out that the machine had been fundamentally developed. Outwardly, the aircraft differs from its predecessors in that it has duck wings and a much larger radome. In the further development, the focus was placed on greater maneuverability in order to increase the combat power. Therefore the stability of the machine was reduced and at the same time a digital electrical control was installed for the first time.

In combination with the duck wings, the machine became significantly more agile than the very stable flying Su-27. The dry thrust of the engines has been increased, but not enough for the machine to be super cruising. The fuel consumption could also be reduced; however, it remained very high compared to American and European engines. The limitation of the angle of attack could be increased to 30 ° and the use of composite materials and aluminum-lithium alloys made it possible to keep the weight within acceptable limits.

The N-011 multi-range radar was housed in the greatly enlarged radome. Its range is specified as 160 km for targets with a radar reflecting area of ​​3 m². It can locate up to 20 targets and allows you to fight six of them at the same time. The Su-35 was equipped with a rear-facing radar, the range of which is specified as up to 50 km, although the target size remains unclear. In theory, it could also be used to control rear-fired guided missiles. The ECM systems were housed at the wing tips.

A total of ten single-seat prototypes of the Su-35 and two further Su-35UB double-seaters were built for training purposes. An eleventh prototype (T-10M-11) was equipped with a 2D thrust vector control and was named Su-37 Terminator.

Second draft Su-35S/BM

After the first draft of the Su-35 failed to show any export success, the development of a new Su-35 began in 2003. The Su-35S (internal code: BM) was presented in 2007 and completed its maiden flight on February 19, 2008. The machine is based on the Su-27SM, which is why the Russian air force initially used the designation Su-27SM2. The third prototype was lost on April 14, 2009 during flight tests. The test pilot was able to save himself with the ejection seat and was uninjured.

Nonetheless, at the end of 2009, series production for the Russian air force began. They initially planned the acquisition of 24 to 36 machines. At MAKS 2009, at which the Su-35S was also demonstrated, the Russian Air Force finally ordered 48 machines that were to be delivered between 2012 and 2015. Another contract for the delivery of an additional 56–64 machines followed in the summer of 2014. The number of machines ordered for Russia will thus initially amount to 104–112. The first production aircraft took off on May 3, 2011 in Komsomolsk am Amur with Sergej Bogdan at the wheel for its maiden flight.

Construction and technology

Airframe

The standard airframe of the Su-27 series was largely retained in order to maintain the same aerodynamic configuration as the Su-27. The changes included the more frequent use of titanium alloys to increase cell life to 6,000 hours without excessively increasing curb weight. An overhaul is necessary every 1500 flight hours. The air brake has been removed, its task is now taken over by the opposite movement of control surfaces. Since an increase in the curb weight could not be avoided, the landing gear was reinforced and the nose landing gear was equipped with a double wheel.

The internal fuel capacity has been increased to 11,500 kg. For air refueling there is a fold-out refueling probe on the left side of the cockpit. To improve maneuverability, a four-fold redundant fly-by-wire system of the type KSU-35 from MNPK Avionika was installed, which also automatically removes the fighter jet. For the first time, the effective radar reflective surface (RCS) was reduced on a series machine of the Su-27 series. The cockpit canopy was given a reflective coating and edges visible from the front were coated with magnetic absorber material. The compressor blades and air inlets of the engines were also coated, which significantly reduced the RCS of the inlets compared to the Su-27.

Cockpit

The cockpit has been completely revised and is now designed as an EFIS. It mainly consists of two large MFI-35 color displays, each measuring 229 × 305 mm and 1400 × 1050 pixels each, on which sensor and flight data can be displayed. There are input keys on the edges of the screens, and the HOTAS concept was also implemented. The IKSh-1M head-up display has a field of view of 20 × 30 °. The pilot sits on a Zvezda-K-36D-3.5E ejection seat with zero-zero capability.

Avionics

The main sensor is the mechanically swiveled passive phased array radar Irbis-E (snow leopard), which is based on the N011M Bars of the Su-30MKI, has an antenna diameter of 900 mm and transmits in the X-band. The problem of power loss with electronic swivel angles of over 40 ° has been solved so that the full swivel range of ± 60 ° in elevation and azimuth can now be used. Since the mechanical tracking has been retained, the antenna can still be swiveled by ± 60 ° in azimuth and rotated by 120 °.

The signal processing processor has been replaced by the Solo 35 digital computer, which allows up to 30 targets to be tracked in Track-While-Scan mode and eight of them to be engaged in simultaneously. In air-to-ground mode, four targets can be pursued and two of them can be fought at the same time. The bar’s original 7 kW traveling wave tube has been replaced by two 10 kW tubes. The usable frequency band is said to have doubled compared to the bars. The official detection range is given as 90 km against a target with a radar reflecting surface of 0.01 m². Since this corresponds roughly to the detection range of an E-3 Sentry without a RISP upgrade, the information is very unreliable. If, on the other hand, the antenna gain of the bar and its pulse power of 4.8 kW with a 7 kW feed is taken as a reference, a pulse power of 13.7 kW can be calculated for the Irbis-E with the same losses.

If the location range of about 140 km for a target with an RCS of 1 m² for the bar is taken as a reference, a location range of 182 km can be calculated using the radar equation. Like all machines in the Su-27 family, the Su-35BM has a rear radar to improve the pilot’s awareness of the situation. This NIIP N012 was adopted by the SU-27/30 and achieves a detection range of 20 NM (37 km) against a target with a radar reflecting area of ​​1 m². The radar scans ± 60 ° in azimuth and elevation and is also used to coordinate active and passive countermeasures.

The OLS-35 consists of an infrared sensor, a video camera and a laser range finder and is located at the front right in front of the cockpit. In a search range of ± 90 ° in azimuth and + 60 / −15 ° in elevation, up to four aerial targets can be tracked simultaneously. The detection range against subsonic targets is given as 50 km on approach and 90 km in pursuit. The laser rangefinder is used to precisely track individual targets. The measurement accuracy for air targets at a distance of 20 km and ground targets at a distance of 30 km is ± 5 meters.

For electronic countermeasures, interference containers of the type SAP-518 can be mounted on the wing tips, which operate in the frequency range from 5 to 18 GHz. The antennas of the radar detectors (ESM) L150 from Pastel in Omsk are located on the left and right of the tail unit and on the side of the air inlets. They cover the frequency range from 1.2 to 40 GHz and allow location with an accuracy of 5 °. In addition, an infrared-based rocket detector with six sensors, which is supposed to cover the entire airspace within a radius of 30 km, and a laser warning system with two sensors complement the self-protection equipment. Export machines of the Su-30 series such as the Su-30MKM are, for example, equipped with the MAW-300 missile detector from Saab Avitronics.

Engines

Two 117S turbofan engines from Saturn are used as propulsion. Due to the limited budget of the Russian air force, the development of the engine was carried out by the companies Suchoi (40%), Saturn (30%) and UMPO (30%) from their own resources. The engine is based on the AL-31F. The fan was enlarged by 3% from 903 mm to 932 mm, new high and low pressure turbines were installed and a new FADEC was installed. The thrust vector nozzle is based on the AL-31FP and can deflect the exhaust jet at a rate of 30 ° / s by ± 15 ° in one axis. Compared to the original model, the service life of the engine has been more than doubled from 1500 hours to 4000 hours.

The MTBO value could be increased from 500 to 1000 hours, whereby the time until the first overhaul is 1500 hours. The MTBO value of the thrust vector nozzle could be adapted to the engine, while the nozzles of the Su-30MKI already have to be overhauled every 500 hours. KnAAPO specifies the thrust per engine as 8800 kp dry and 14,000 kp wet as well as 14,500 kp in “special mode”.

There are no statements from Suchoi or KnAAPO that the Su-35S can reach supersonic speed with this engine without an afterburner. According to Igor Dyomin, head of the Su-35 project, the Su-35S reached supersonic speed with these engines in the first flight tests without the use of the afterburner. The final speed as well as the possible weapon mountings should be determined in further tests.

Versions

Su-27M / Su-35 – Prototype series of a single-seat air superiority fighter.
Su-35UB – Two-seat version of the Su-35.
Su-35S – Modernized multipurpose fighter.
Su-35BM – Internal manufacturer designation of the Su-35S.
Su-37 – Prototype; Version of the first Su-35 with more powerful AL-37FU engines and 2D thrust vector control.

Technical data

Characteristic	Su-27M/Su-35	Su-35S
Type	air superiority fighter	multi-role fighter
Length	22.18 m	21.94 m
Span	14.70 m	15.30 m
Wing area	62.04 m²	62.04 m²
Wing extension	3.48	3.77
Wing loading	minimum (empty weight): 297 kg / m² nominal (normal takeoff weight): 430 kg / m² maximum (max. takeoff weight): 548 kg / m²	minimum (empty weight): 306 kg / m² nominal (normal take-off weight): 408 kg / m² maximum (max. take-off weight): 556 kg / m²
Height	6.32 m	5.93 m
Empty weight	18,400 kg	approx. 19,000 kg
Normal takeoff weight	26,700 kg	25,300 kg
Max. takeoff weight	34,000 kg	34,500 kg
Max. fuel capacity	7,500 kg (internal)	11,500 kg (internal)
Fuel ratio	0.29	0.38
Loads	−3g to + 9g	−3g to + 9g
Top speed	2095 km / h or Mach 2.00 (at 10,975 m) 1396 km / h or Mach 1.14 (at sea level)	Mach 2.25 (at 11,000 m altitude) [21] approx. 1400 km / h or Mach 1.14 (at sea level)
Service ceiling	approx. 18,000 m	19,000 m
Max. rate of climb	n/a	>280 m / s
Use radius	n/a	1580 km
Max. Range	3680 km	4500 km
Engines	two Saturn / Ljulka-AL-31FM turbofan engines	two Saturn 117S turbofan engines
Thrust	with afterburner: 2 × 122.60 kN without afterburner: 2 × 79.43 kN	with afterburner: 2 × 142.97 kN without afterburner: 2 × 86.27 kN
Thrust to weight ratio	maximum (empty weight): 1.36 nominal (normal take-off mass): 0.94 minimum (max.starting mass): 0.74	maximum (empty weight): 1.53 nominal (normal take-off mass): 1.15 minimum (max.starting mass): 0.84

Armament

Armament of the Su-27M / Su-35

Fixed armament in the bow
1 × 30-mm automatic cannon Grjasew-Schipunow GSch-301 (9A-4071K) with up to 150 rounds of ammunition

Gun loading of 8000 kg at 14 external load stations

Air-to-air guided missile
2 × start rails for 1 × Nowator KS-172 Mod.1 / Mod. 2 AAM-L (R-72) each – radar-controlled for ultra-long distances
6 × AKU / APU-470 start rails for 1 × GosMKB Wympel R-27ER (AA-10C “Alamo”) each – semi-active radar-guided for extended medium distances
2 × AKU / APU-470 start rails for 1 × GosMKB Wympel R-27ET (AA-10D “Alamo”) each – infrared-controlled for extended medium-range distances
6 × AKU / APU-470 start rails for 1 × GosMKB Wympel R-27R (AA-10 “Alamo”) each – semi-active radar-guided for medium-haul routes
6 × AKU / APU-470 start rails for 1 × GosMKB Wympel R-27T (AA-10 “Alamo”) each – infrared-controlled for medium-haul routes
6 × AAKU / APU-170 start rails for 1 × GosMKB Wympel R-77MP each (RWW-AE or AA-12 “Adder”) – radar-guided for medium-haul routes
6 × P-12-1-D start rails for 1 × GosMKB Wympel R-73E / R-74 (RWW-MD or AA-11 “Archer”) – infrared controlled for short distances

Cruise missiles
4 × AKU-58 starting rails for an MKB Raduga Ch-59ME “Owod” (AS-18 “Kazoo”)
6 × Zvezda Ch-35 “Uran” (3M24 or AS-20 “Kayak”) – anti-ship guided missiles

Air-to-surface guided missile
6 × AKU-58M starting rails for 1 × GosMKB Wympel Ch-29L (AS-14 “Kedge”) each – laser-guided
6 × AKU-58M starting rails for each 1 × GosMKB Wympel Ch-29T (AS-14 “Kedge”) – TV-controlled
4 × AKU-58 starting rails for a Zvezda-Strela Ch-31P “Taifoon” (AS-17 Krypton) – passive location for radar control
4 × AKU-58 launch rails for a Zvezda-Strela Ch-31A “Taifoon” (AS-17 Krypton) – actively radar-guided to combat ships

Guided bombs
3 × BD-4 suspension for each 1 × region JSC KAB-1500L-F (laser-guided 1500 kg bomb)
3 × BD-4 suspension for 1 × region JSC KAB-1500S-E (satellite navigation-guided 1500 kg bomb)
6 × BD-3U suspension for 1 × GNPP KAB-500KR each (television-controlled 500 kg bomb)
6 × BD-3U suspension for each 1 × GNPP KAB-500S-E (satellite navigation-guided 500 kg bomb)
6 × BD-3U suspension for 1 × GNPP KAB-500L each (laser-guided 500 kg bomb)

External container
3 × additional tanks for 3000 liters of kerosene each
1 × Tekon / Elektron APK-9E data transfer case for Ch-29, Ch-59
1 × EloKa and reconnaissance container

Armament of the Su-35S

Fixed armament in the bow
1 × 30-mm automatic cannon Grjasew-Schipunow GSch-301 (9A-4071K) with up to 150 rounds of ammunition

Gun loading of 8000 kg at twelve external load stations

Air-to-air guided missile
5 × R-37 long-range air-to-air missiles
8 × Wympel R-27ER (AA-10C Alamo) – medium-range air-to-air missiles, semi-active radar seeker
4 × Wympel R-27ET (AA-10D Alamo) – medium-range air-to-air missile, infrared seeker head
12 × Wympel R-77 (RWW-AE, RWW-SD, AAM-AE or AA-12 Adder) – medium-range air-to-air missiles, active radar seeker
6 × Wympel R-73E (RWW-MD or AA-11 Archer) – short-range air-to-air missiles, infrared seeker head

Air-to-surface guided missile
6 × Ch-29L / T (AS-14 Kedge) – laser or video steered
6 × Ch-31P (AS-17 Krypton) – anti-radar missiles
6 × Ch-31A (AS-17 Krypton) – anti-ship guided missile
5 × Zvezda Ch-35 “Uran” / 3M24 (AS-20 “Kayak”) – anti-ship guided missiles
5 × Raduga Ch-59MK (AS-18 Kazoo) – multipurpose guided missile
5 × Raduga Ch-58UShKE (AS-11 Kilter) – anti-radar missiles

Guided bombs
3 × BD-4 suspension for 1 × region JSC KAB-1500L-F (laser-guided 1500 kg bomb with HE, aerosol and a bunker-breaking warhead) [24]
8 × BD-3U suspension for 1 × region JSC KAB-500L / Kr (laser / video-guided 500 kg bomb)
8 × BD-3U suspensions for 1 × region JSC KAB-500S-E (satellite navigation-guided 500 kg bomb)

External container
2 × additional tanks for 2000 liters of kerosene each

Commitment

At the end of January 2016, four Su-35S of the Russian Air Force were relocated to Latakia as part of the Russian military operation in Syria.

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