Su-35 Super Flanker : The Last Flanker?

SUKHOI 35 SUPER FLANKER 

“In strategic terms the Su-35S is a game changer, as it robustly outclasses all competing Western fighter aircraft other than the F-22A Raptor. Deployed in significant numbers it is capable of changing the balance of power in any region where this occurs. This reality does not appear to be widely understood in most Western air forces.”

The Su-35 aircraft is designed by “Sukhoi Design Bureau”, but its production is mastered at the Komsomolsk-on-Amur Aircraft Production Association named after Gagarin.

The impressive Su-35S is the latest incarnation of the T-10 family of fighter aircraft. It would be fair to describe this aircraft as the pinnacle of current conventional fighter design, blending a superb basic aerodynamic design with advanced engine, flight control and avionic technology.

The current Su-35S, ordered in 2009 for the Russian Air Force, was the result of a series of design studies for a deep modernisation of the Su-27M design. This was actually more of a deep re-engineering of the basic design in the manner of the F-15E against the F-15C performed during the 1980s. The new Su-35BM retained the basic aerodynamic design and much of the structural design of the late model Flanker, but sees important aerodynamic enhancements and completely new engines and digital systems.

Notable changes include the removal of the dorsal speedbrake, additional internal fuel, and plumbing for AAR and external drop tanks. A quadruplex digital flight control system is used. The Item 117S engines, which use key components of the Al-41F supercruising core, are employed. The Su-35S is the first non-US fighter with substantial sustained supersonic cruise capability, which provides this aircraft with an enormous energy advantage against conventional opponents in most regimes of air combat.

SU-35 MULTI-ROLES FIGHTER   

On the world fighter market Russia’s Sukhoi is pinning its hopes, in the near future, on a substantially modernized Su-35 multi-role fighter. The model must be an interim type between today’s Su-30MK in various configurations and a prospective fifth-generation fighter, whose deliveries may start in the second half of the next decade. The Su-35 is a 4++ generation aircraft employing technologies of the fifth generation. They make it superior to all other 4th generation fighters now under development worldwide. In 2009-2015, thanks to these technologies, the Su-35 will dominate the world market, outperforming other proposed multi-role fighters. 

The first experimental Su-35, completed in summer 2007 at Komsomolsk-na-Amure Aviation Production Association (KnAAPO) first appeared at Russia’s MAKS-2007 air show.

THE SU-35 SYSTEMS: 

•          Supreme flight performance, superagility mode

•       Long range information targeting system
•          Advanced jam-resistant secure communication system providing data link between the aircraft and ground-based command centers
•          High-performance air-to-air and air-to-surface long- medium-, and short-range guided weapon mounted externally on 14 hardpoints
•          High-performance EW and ECM systems
•          Electronic reconnaissance system
•         Design features aimed at stealth capability enhancement
•          New indication and signaling system with Multifunctional Display, notable for its enlarged capacity and advanced quality of provided data
•          In-flight refueling system.

 

WHY SU-35 NOT HAVE CANARD? 

As one of my readers noted and some articles from library, internet and from Airman chatting seem to describe 2 different SU-35s. One was a mid-life modernized SU-27 Flanker, but there’s also a much more re-engineered “SU-35” variant with canards, thrust vectoring and so on which has been confused with (and possibly re-designated between) the SU-37. So… what do we mean by “SU-35”? It is the last Flanker?. This article explains the sources of the widespread confusion regarding the SU-35’s layout and key characteristics, reviews what is now known about the platform, and tracks its development. Those developments are likely to have broad consequences. The aircraft has a home customer in the Russian Air Force, and the SU-35 is being positioned to succeed most SU-30MK variants as Russia’s fighter export of choice within the coming decade.

Until very recently, only KnAAPO had listed the SU-35 as a product on its site while Sukhoi now does so as well, but Irkut does not. If this seems confusing, it’s because Sukhoi subcontracts production to affiliate firms known IAIA (Irkut) and KnAAPO (Komsomolosk un Amur). Each has their own intellectual property, and their own interests. In addition, the designation “SU-35” has been used in several different contexts over the years. It has been referred to, and even photographed, in ways that referred to both mid-life Flanker upgrades and canard-equipped next-generation aircraft. KnAAPO’s site added the confusion by showing SU-35 pictures on its type page and gallery that display the aircraft both with and without canard foreplanes.

The current “SU-35”, which has been definitively described by Sukhoi, appears to be something of a compromise between the upgrade and full redesign visions. Reader assistance, and sources from Sukhoi and various media, offer an outline of its key systems and characteristics:

• ·         N035 Irbis-E PESA (Passive Electronically Scanned Array) Radar, a follow-on to the Bars-M.
• ·         No canards.
• ·         Rear-looking self-defense radar in shorter tail sting.
• ·         AL-37FU/ 117S thrust-vectoring turbofan engines rated at 142-147kN.
• ·         Extended high-lift devices with large flaperon occupying the full trailing edge of the wing.
• ·         L175M Khibiny-M electronic-warfare self-defense system.
• ·         Reduced-area empennage.
• ·         Larger Air Intakes.
• ·         New and lighter systems, including quadruple digital fly-by-wire flight-control system.
• ·         New man-machine interface with fully-glass cockpit with two large LCD screens and helmet mounted display.

 

SU-35 MODERSIATION

The Su-35 has long been a brand name in the aviation world. Since 1992, an export version of the Su-27 fighter where created under the order of the Russian Air Force and has been demonstrated at international air shows. At the turn of the millennium, Su-35 fighters participated in the tenders of Korean and Brazilian air forces. By the mid-decade of the new century, a general concept emerged of a considerably modified Su-27 fighter, which retained the name of Su-35. 

What is new in the Su-35? First off, the fighter will get an improved airframe, which will dramatically increase its service life to 6,000 hours, 30 years of operation which is the time before the first test and recondition and the between-repairs period has been increased to 1,500 hours, or 10 years of operation. Aerodynamically it is similar to the Su-27. But unlike the Su-30MKI it will feature no canard fins. All the three channels will have electrically signaled control without mechanical cabling. The use of a new integrated control system was developed by MNPK Avionika Moscow-based Research and Production Association which is  simultaneously performing functions of several systems likes remote control, automatic control, limiting signals system, air signals system, chassis wheels braking system – will enhance the fighter’s handling capability and maneuverability.

Among the Su-35 design features, worth of note is the absence of an overhead brake flap, a standard characteristic of the Su-27. Its functions are performed by an active rudder. The Su-35 chassis has been reinforced because of the increased takeoff and landing weight of the aircraft. For the same reason, the front bearing has two wheels. The improved radar stealth reduces the reflectance of the Su-35 in the X radio waveband and in the angle range of ±60°. 

To enhance the combat effectiveness and expand the employment area of the aircraft, it was decided to create a multipurpose maneuverable fighter combining high agility and capacity to intercept air targets normally attacked by the Su-27 with a capability to attack ground and water surface targets by both unguided and guided, including high precision, weapons. The Su-35 met these requirements.

The Su-35 is intended to destroy existing and prospective remotely piloted vehicles, cruise missiles and other maneuverable targets against the earth background, day and night and in all weathers, to deliver preemptive strikes at any air enemy, including hardly discernible visual objects, to engage ground and water surface targets by carrying out standoff attacks with diverse guided weapons, including high-precision ones.

 The Su-35 has now acquired a newly developed wing with increased relative thickness, accommodating a large amount of fuel. As in the Su-27, the wing of the Su-35 is provided with high-lift devices featured as deflecting leading edges and flaperons acting as both the flaps and ailerons. In flights at subsonic speeds, the wing profile curvature is changed by a remote control system which deflects the leading edges and flaperons versus the angle of attack.

The horizontal tail of the aircraft is essentially a differentially adjustable stabilizer each panel of which is provided with its own quick-acting electro-hydraulic actuator. For a greater combat employment range, the aircraft is fitted with an in-flight refueling system. Inasmuch as a refueling flight of the aircraft may be quite extended (6 - 8 hours or longer) and is only limited by the pilot's physical conditions, its cockpit is provided with containers to store reserves of food and water, and a waste disposal system. The amount of oxygen is increased too. The KD-36DM series ejector seat is set with its back inclined at 30 deg., which helps the pilot resist aircraft accelerations in air combat.

The Su-35 avionics equipments:

• ·         New-generation forward-looking pulse-doppler radar with a phased antenna array
• ·         Rearward-looking radar
• ·         Optical locator with combined functions of infra-red imager and laser range finder
• ·         Weapons control system
• ·         Helmet-mounted target designator
• ·         Radio reconnaissance system
• ·         Defense complex
• ·         Integrated display system using three high-contrast monochrome CRT's
• ·         Communications and navigation equipment

Su-35S Electro-Optical System turret (© Vitaliy V. Kuzmin)

The UOMZ Sapsan E Electro-Optical Targeting System pod is likely to be offered as an alternative to the licenced French Thales Damocles targeting pod (©  Vitaliy V. Kuzmin)

The heavyweight high power KNIRTI SAP-14 Support Jammer ECM pod is a Russian analogue to the US ALQ-99E pod carried on the EA-6B Prowler and EA-18G Growler. It was developed for Flanker family aircraft and is carried on a large centreline pylon. To date little has been disclosed about this design, but it has been observed on the Su-30MK Flanker G/H and Su-34 Fullback. It operates between 1 GHz and  4 GHz (© Vitaliy V. Kuzmin).

The KNIRTI SAP-518 ECM pod is a new technology replacement for the established L005 Sorbstiya series wingtip ECM pods. It operates between 5 GHz and 18 GHz (©Vitaliy V. Kuzmin)

AVIONIC SYSTEMS

The core of the Su-35 cockpit instrumentation suite are two full-color multi-function liquid crystal displays of MFI type, a multi-function panel with a built-in display processor, a wide angle collimatory display on the windshield and a control and indication panel.

The cockpit has a 'glass cockpit' design, utilizing two large 15" have a resolution of 1400x1050 pixels, multi-function color LCD displays, a head-up display and full HOTAS functionality. The main sensor is an X-band E-Slavia radar allowing detection and tracking up to 30 air targets while scanning a wide sector (track while scan). The radar and fire control can simultaneously engage up to eight targets. Production models will be fitted with the Tikhomirov NIIP Irbis radar, capable of detecting and tracking aerial targets with average radar cross-section of three square meters, operating at ranges of up-to 400 km. Irbis offers a wide area coverage of Irbis 70 to 120° with azimuth resolution of (in 2 -2.5 times), increased range, and better ECCM compared to its predecessors. The development of this radar began in 2004. The system completed ground tests in the lab and is preparing for the initial test flights on a Su-30MK2 testbed.

They are intended for reception, processing and production, in a multiple window mode, of graphic, numeric, alphabetic and symbolic information. They also present televised information received from onboard TV sensors and impose on it synthesized numeric, alphabetic and symbolic information. Besides, they produce and send video signals in a digital format to the video record unit. The multi-function panel with a built-in display processor presents the required information and issues commands by pushing the buttons on the button array at any time in flight. The airborne collimatory display with a built-in processor monitors the space beyond the cockpit. The information is processed by control signals. The collimator angle of view is 20x30°. 

The onboard systems and armament in the new cockpit of Su-35 are controlled by buttons and switches on the aircraft control joystick and engine control levers as well as by a button array on multi-function displays. Thus the HOTAS concept is realized on this type of aircraft. The displays and some other avionics systems of Su-35 are developed by Instrument Design Bureau of Ramenskoye and affiliated companies of Tekhnokompleks Research and Production Association.

Su-35S cockpit

SU-35 WEAPONS SYSTEMS

Overall, over 70 versions of guided and unguided weapon stores may be employed, which allows the aircraft to fly most diverse tactical missions. The automatic flight control system of the Su-35 makes all phases of its flight automatic, including the combat employment of its weapons.

The armament of the aircraft consists of a fixed gun, aerial bombs, guided and unguided missiles. The missile-bomb armament is arranged at 12 hardpoints and comprises:

• ·         Prospective medium-range, type RVV-AE, air-to-air 'fire-and- forget' active homing missiles;
• ·         Medium-range air-to-air missiles of the R-27 family with semi- active radar and passive IR guidance, with engines both conventional and having increased power-to-weight ratio
• ·         Highly agile missiles of the R-73 class for close air maneuver combat with passive IR guidance and combined (air- and gas-dynamic) control
• ·         The X-31A and X-31P air-to-ship and air-to-radar missiles with active and passive radar guidance and capable of flying at a supersonic speed
• ·         The X-29 air-to-surface missiles with laser and TV guidance
• ·         Incendiary tanks, 100-kg, 250-kg and 500-kg bombs and bomb clusters for various purposes, including those fitted with a brake and used for low-altitude attacks

Su-35S prototype B/N 902 on display at MAKS 2009 with a KAB-1500L and air launched Kh-35UE Harpoonski (© Vitaliy V. Kuzmin)

The primary close combat weapon to be carried by early production variants of the Su-35S is the KTRV RVV-MD, an extended range evolution of the R-73/74 / AA-11 Archer with a jam resistant two colour scanning seeker and a laser proximity fuse. Note the wideband ZnS or ZnSe IR window replacing the MgF₂ design used in earlier variants (© Vitaliy V. Kuzmin)

 

 

The primary BVR weapon to be carried by early production variants of the Su-35S is the KTRV RVV-SD, an extended range evolution of the R-77 / AA-12 Adder similar to the AIM-120D. Note the laser proximity fuse supplanting the radiofrequency fuse (© Vitaliy V. Kuzmin).

SU 35 117S ENGINES 

Another important difference of the Su-35 from predecessors from the Su-27 family is the use, in its power plant, of new engines with an increased thrust. Those engines, known as 117S, have been developed by NPO Saturn Research and Production Association.

In terms of engineering, the engines are substantially modified AL-31F production engines employing fifth-generation technologies. They use a new fan, new high and low pressure turbines, and a new digital control system. A provision is made for using a vectored thrust nozzle. The modernization has increased the engine special mode thrust by 16%, up to 14,500 kgf. In the maximum burner-free mode it reaches 8,800 kgf. Compared to today’s AL-31F engines, their capabilities will grow substantially, by 2 to 2.7 times. For instance, the between-repair period will grow from 500 to 1,000 hours (the operating period before the first overhaul is 1,500 hours). The designed period will vary between 1,500 and 4,000 hours.

The 117S engines will be co-produced by Ufa-based Motor Building Association and Rybinsk-based NPO Saturn Research and Production Association. The first production 117S engines were delivered to KnAAPO in early 2007 for testing on the first experimental Su-35 aircraft.

The 117S powerplant (© Vitaliy V. Kuzmin)