Su-35S - the pinnacle of Flanker's evolution (Part 1)

Airplane appearance

Forming the aerodynamic appearance of the Su-35S, the specialists of the experimental design bureau named after P.O. Sukhoi tried to make changes to the basic design so as to eliminate or reduce the negative aspects revealed during the operation of the Su-27 (by that time it had been in service for almost thirty years). They also attempted to implement the advanced technologies that had become available in such a way that unnecessary changes were made to the time-tested design of the Su-27. This approach made it possible to shorten the design and launch times, as well as the volume of testing.

The aerodynamic improvements implemented include redesigning the air intakes for more airflow and less harmful drag. Previous versions of the Su-27 family aircraft had a large air brake on the upper surface of the fuselage. Its function on the Su-35S is performed by differentially deflected (turning inward) air rudders. The larger and heavier front fuselage required a reinforced front landing gear with two wheels instead of one on the Su-27.

The cockpit is designed to comply with the HOTAS concept, according to which the pilot's hands are on the flight control stick and throttle. The information and control field is built on two multifunctional indicators MFD-35 with color liquid crystal matrices 9x12 feet (23x30 cm) in size and a resolution of 1400x1050 pixels. The indicator against the background of the windshield OKSH-1M has a solid viewing angle of 20 by 30 degrees. This is significantly more than that of previous models, which is reflected in the name - "wide-angle optical collimator".

The integrated flight control system KSU-35 was developed by MNPK Avionika. It replaced several less advanced systems on board the Su-27, provides better flight performance and, moreover, implements the concept of "active safety".

Measures have been introduced to reduce the aircraft's radar signature on radar screens with radiation in the centimetre range, which is typical for fighters. True, the effective scattering area (ESR) is higher than that of the F-22A and F-35. The tasks of electronic countermeasures are performed by the system of the Khibiny family of the L-175M brand.

Radar

The onboard radar station N-035 "Irbis-E" was developed by Research Institute of Instrumentation named after V.V. Tikhomirov. It is an all-weather multifunctional broadband system for detecting, identifying and tracking air, ground and sea targets, illuminating them with a radio beam and issuing target designations to missiles with radar homing heads. In the mode of mapping with a real beam with a synthetic aperture, the Irbis provides a resolution of one meter.

Work on the H-035 began in 2004 and by September 2008, five prototypes were ready for testing. Technologically, "Irbis-E" became the next step in the development of a line of passive radars with a passive phased antenna array, following the N-011M "Bars" on the Su-30MKI and "Zaslon" on the MiG-31.

Previously published interviews with the general director of Research Institute of Instrumentation Yuri Bely contain information that the average radiation power of the N-035 is 5 kW, and the peak power is 20. In the middle of the first decade of the 21st century, these were record numbers for fighter radars. When working on a target with an EPR of three square meters - typical for front-line combat aircraft - the maximum detection range is «about four hundred kilometres». Ocean-class ships such as an aircraft carrier are found at the same distance.

"Irbis" can track up to thirty air targets while scanning space in search of others. It provides guidance of missiles with an active homing head of the RVV-AE type at eight air targets simultaneously. When working on ground targets, target designation is issued to four missiles at once, while the radar station does not stop monitoring the situation in the air. The average power in target illumination mode at the selected frequency can reach 2 kW.

Unlike the latest American and European models of aircraft radars, the H-035 uses not an active (composed of solid-state transceiver modules), but a passive antenna array. Sometimes the foreign press presents this fact as a technological lag. In fact, this is not the case. Despite the rapid development of AESA-type radars, passive phased systems retain a significant share of the market, since they are much cheaper, attracting and retaining a significant number of buyers. At the same time, in the event of a head-to-head approach of the Su-35 and F-22A fighters, due to the high power of the emitter, the Irbis will ensure the detection of the enemy at a greater distance and enable the first shot.

Among the weak points of PFAR, a relatively narrow viewing angle is often called. This drawback on the Su-35S was eliminated by using a mechanical "turnover". Antenna with a diameter of 900 mm is deflected vertically and horizontally by means of an electro-hydraulic drive. This solution allows the actual viewing angle to be doubled to 240 degrees. This achieves parity with the best fighter radars.

In addition to the radar, the Su-35S fire control system includes an electro-optical system. It includes six conformal sensors located in different parts of the airframe. They provide a circular view of the surrounding space with the output of the processed information to the MFD in the cockpit. There are also two detectors that signal when the laser beam is irradiated.

The containerised optical locator OLS-NT is designed for viewing the earth's surface, and the OLS-35 (OLS-VT), located in front of the canopy of the pilot's cockpit - the front hemisphere, provides an overview in azimuth -/+ 90 degrees, and -15/+50 degrees to the horizon. The Su-27 fighter is detected at a distance of up to 90 km in the front and 35 in the rear hemisphere.

Power point

The Su-35S is a twin-engine aircraft with a thrust vector deflection system. Developed by Moscow engineers from the Experimental design bureau named after Arkhip Lyulka AL-41F1 engines are assembled at the Ufa plant. The first prototype went for testing in March 2004 aboard the Su-27M "flying laboratory", tail number 710.

AL-41F1 (Product 117C) is a further development of the successful AL-31F family, through the introduction of certain advanced technologies obtained during the creation of the first modification of the AL-41F, which passed tests, but was not serially built.

The updated motor differs by an enlarged, by 27 mm, inlet diameter - up to 932 mm. Its high and low pressure turbines, as well as a digital control system with full responsibility (FADEC type) and other new items are based on AL-41F technologies. Their introduction made it possible to raise the thrust up to 8800 kg(f) in the "maximum" mode and up to 14500 kg(f) in the "full afterburner".

The latter figure is a couple of tons more than the corresponding indicator of the original AL-31F. The advanced technologies introduced have allowed the maintenance interval (TBO) to be extended to 1,500 hours, and the total operating time to 4,000.

Flight tests at the flying laboratory confirmed the characteristics of the "Product 117C" declared by the engine builders. A great achievement was the thrust-to-weight ratio in the region of 9-10 units, which corresponded to the target for the fifth generation fighter engine. The replacement of the serial AL-31F with the experimental AL-41F1 gave the 710 board a tangible increase in thrust in transonic modes.

Restrain the "predator"

Development of the aircraft in serial form (Su-35 with the index "S") began in 2005. By that time, the United States had created and adopted the F-22A Raptor, a fifth-generation fighter.

It is logical to ask the question, to what extent is the Su-35S close to the F-22A in terms of technical perfection, where is it inferior to it and in what superiority? Such a comparison is appropriate if only because the geometrical dimensions of the "drying" and "predator" are close. The length is 21.9 meters versus 18.92, and the wingspan is 14.75 meters versus 13.56. Maximum takeoff weight 38.8 tons against 38, empty curb weight - 19 tons against 19.7.

One of the characteristic features of the fifth generation fighters is considered to have internal weapons bays. Unlike the Raptor, the Su-35S does not have them. However, the Russian aircraft has a large volume of internal fuel tanks. This gives it an advantage in terms of range and duration.

Since the development of the Su-35S began after the F-22A was put into service, at that time the characteristics of the "Raptor" and its on-board equipment were known. Accordingly, the specialists of the RF Ministry of Defense and the Experimentl design bro named after P.O. Sukhoi sought to create an improved version of the Su-27 so that it could contain the "predator" in a number of typical situations of real combat operations. And as far as can be judged from the experience of the counter-terrorist operation in Syria, the desired was achieved.

Supplies

The first public demonstration of the Su-35S took place at the MAKS-2007 air show. The prototype was not yet ready for flight, and therefore was demonstrated only on a static site. Flight tests began in February 2008. When the Su-35S prototype first took to the skies, the Americans already had 112 serial "Raptors" at their disposal.

The Russian Ministry of Defense placed the first order for 48 Su-35S in 2009, with delivery during 2012-2015. Meanwhile, deliveries of US Air Force predators ended in 2011. In total, they received 195 aircraft, including eight for various tests.

The Pentagon has already stopped funding the program for the serial production of "raptors", and the Russian military is still buying serial Su-35S. In December 2015, they placed a repeat order for fifty aircraft. It is expected that the completion of deliveries on it will take place in the next few months.

During a recent working trip with a visit to key defense plants in the Far Eastern regions, Defense Minister Sergei Shoigu announced the imminent placement of a third order for the Su-35S. “By the end of the year, we plan to conclude an additional state contract for the supply of multifunctional Su-35S aircraft. The amount of the contract will amount to 70 billion rubles,”- said Sergei Kozhugetovich at a meeting with representatives of the regional administration and the military-industrial complex.

Foreign customers

As of the summer of 2020, the Su-35S was supplied to only one foreign customer - the People's Liberation Army of China. A foreign buyer submitted an application for the purchase of a batch of aircraft in 2011.

According to domestic media reports, Moscow was ready to sell a unit of marketable products at $85 million per unit, subject to a sufficiently large order. The negotiation of the contract proceeded slowly, but, in the end, the parties agreed and signed it. In full accordance with the agreements, during 2016-2018. The People's Liberation Army Air Force received 24 aircraft.

A couple of years ago, Indonesia placed an order for eleven aircraft, but implementation is delayed. According to the publication of the newspaper "Kommersant", subscribed to the Su-35S and Egypt, however, there has been no official notification of the deal. However, the very fact of the deal was mentioned in speeches by high-ranking officials in Washington and also by American congressmen. They voiced the idea of ​​imposing sanctions on Cairo for the purchase of advanced weapons from Russia, mentioning among them the Su-35S.

A recent visit to the plant in Komsomolsk-on-Amur by the Russian Minister of Defense brought new information on the export perspective. Selected footage from the video captured Sergei Shoigu at the stand with KnAAZ production plans for 2020-2024. Of greatest interest is the delivery schedule for military-technical cooperation. Presumably, a couple of contracts are being executed: for thirty Su-35S with deliveries in 2020-2021. and for 32-34 cars in 2022-24. Who is the customer is left behind the scenes. List in descending order of probability: Egypt, China, Algeria, Iran, Indonesia and Turkey.

Conclusion

Every time a customer considers options for purchasing an aviation complex, a dilemma arises: choose a time-tested and military one, or take the risk by ordering the latest model - the embodiment of the most advanced technologies, which has not yet been adopted for service or has just entered service.

For those who buy in Russia, the Su-35S can become the "golden mean", since it is a combination of the well-known Su-27 platform and a very advanced set of onboard equipment and weapons.

In general, the Su-35S is a rather complex aviation complex requiring regular maintenance by a competent, motivated technical staff. At the same time, for those customers who choose among the available Russian offers, this model can represent a reasonable combination of the time-tested base platform of the well-proven "flanker" and a very modern complex of onboard equipment and weapons.