Some improvements in Su 35:
New Airframe
Unlike the Su-27M and Su-30MKI, the new Su-35 features the same aerodynamic configuration as the basic Su-27, but with larger wings and engine intakes. The Su-35 is not fitted with canards. The flight performance and manoeuvrability will instead be improved by the advanced KSU-35 fly-by-wire system. It also lacks the larger vertical tails of the Su-27M. Internal fuel capacity has been increased by redesigning the airframe internal volumes. The Su-35 can carry 11,500kg of fuel, which can be increased to 14,300 kg using two underwing drop tanks. Like previous Su-27 derivatives, it has also been fitted with a retractable refueling probe. The new Su-35 lacks the Su-27's large upper air brake owing to advanced rudder control by the KSU-35 system.
Perhaps the most significant improvement is the extensive use of titanium alloys, which increases the aircraft's service life from 4,000 to 6,000 hours, with the time between overhauls growing to 1,500 hours. Another significant improvement is the use of radar absorbing materials (RAM) in various parts of the airframe reducing the fighter's X-band radar cross section within the +/- 60° sector.
New Engine - Saturn 117S
The Su-35 is powered by the NPO Saturn's izdeliye 117S, the new engine is a much improved derivative of the Su-27's AL-31F turbofan based on the company's earlier AL-41F. In its current form the 117S (designated AL-41F1A) offers 16% more thrust than the standard AL-31F, providing 14,500 kgf in afterburner mode and 8,800 kgf in maximum dry setting. The engine's service life has been increased from 1,500 to 4,000 hours, with time between overhauls increasing from 500 to 1,000 hours. Flight testing started in March 2004 with the 117S fitted to the Su-27M '710' testbed. Two production standard 117S engines now power the first Su-35 prototype. Additional engines are being produced for the next two Su-35 prototypes, while development of even more powerful variants of the engine continues. Production of the 117S is shared between the NPO Saturn plant in Rybinsk and the Ufa Engine Production Association (UMPO) in Ufa.
Irbis phased array radar
The Su-35 new fire control system consists of the N035 Irbis multifunction radar system and the OLS-35 electro-optical search-and-track system. The N035 Irbis (Irbis-E for export) is an X-band radar with a 900mm passive phased array. Developed by the Tikhomirov NIIP institute the Irbis radar is a derivative of the N011M Bars radar with wider search zone, increased detection range, wider range of operating frequencies and improved resistance to jamming.
The N035's computing system consists of two Russian Solo-35 processors. A new two-stage mechanical drive mounts the phased array. The passive electronic array scans 60° in azimuth and elevation, while the mechanical steering enables the array to rotate an additional 60° for a wider search zone. The Irbis-E is capable of tracking of up to 30 aerial targets in track-while-scan mode and allows simultaneous engagement of two targets using semi-active radar homing missiles or up to eight targets using active radar homing missiles. The Irbis-E is advertised to be capable of detecting and tracking a fighter-sized target head-on at 350-400 km range using its long-range detection mode within a limited sector. It is also claimed to be capable of detecting 'super-low-observable' targets with 0.01 m2 RCS at 90 km range.
For ground attack, the radar is capable of terrain mapping and target acquisition in different resolutions using Doppler beam sharpening and synthetic aperture focusing modes. In combined ground and air mode, the radar is capable of tracking aerial threats with sufficient precision to engage with active radar homing missiles.
Future options for the Su-35 might include a rear-facing radar such as the N012 to be fitted in the tailboom, but the current Su-35 does not contain such equipment.
OLS-35 electro-optical search-and-track system
Developed by the UOMZ (Ural Optical and Mechanical Plant) in Yekaterinburg, the OLS-35 infrared/laser search-and-track (IRST) system provides the second major sensor of the Su-35's fire control system. The OLS-35 combines a scanning infra-red direction finder and thermal imaging module for target detection and identification with a laser rangefinder/designator and TV camera. The OLS-35 offers sigficant improvements over the OLS-27 of previous Su-27 versions, owing to the use of more advanced electronics, algorithms and software. Information regarding detection ranges and detection/tracking zones vary across sources. The estimated range for detection from a tail-on aspect has been reported to be 70-90 km and up to 40-50 km for head-on engagement for non-afterburning targets. The detection and tracking zone is 55-60 ° upwards, 15 ° downwards, and between 60° and 90° in azimuth. The laser is capable to range aerial target up to 20 km and ground targets at 30 km with a precision of five meters. Alternatively, the Su-35 may be fitted with one of the new electro-optical systems developed by NIIPP (Scientific Research Institute of Precision Instruments Engineering) for the MiG-35.
Glass Cockpit
As with all 4th and 5th generation fighter aircraft, the human-machine interface received considerable attention from its designers. The integrated avionics suite is controlled by the central information and control system. The 'open architecture' system's main components are two central digital computers, digital databus and the 'glass cockpit' display system. The latter consists of two 15" (9x12") MFI-35 full-colour multifunction LCD with 1400x1050 pixels, a multifunction control panel with built-in display unit, IKSh-1M wide-angle collimator HUD and control display unit. The Su-35 cockpit retains the conventional central stick and throttle arrangement of the Su-27, but incorporates the HOTAS principle.
Weapons: Longer-range Missiles
Just like previous Su-27 derivatives, the Su-35 is capable of carrying a maximum payload of 8,000 kg on its 12 external hardpoints. The weapons suite has been further expanded with upgraded variants of existing weapons as well as several new long-range missiles.
The Su-35's air-to-air suite will comprise advanced R-27 versions (R-27ET1, R-27ER1, R-27EP1) and the active R-77 and new R-77M for medium range missiles, the R-73 and new R-74M short range missiles. Up to 12 R-77/R-77M can be carried, with two pairs placed between the nacelles. The Su-35 will also be able to equip up to five long-range missiles. Dubbed 'very-long-range' air-to-air missile, the K-100-1 (izdeliye 172S, 172S-1) has been developed by Novator in Yekaterinburg from its earlier K-172, which was first developed in 1991 for the Su-27M. The missile has a range of 300-400km and is capable of reaching speeds up to 4,000km/h pulling up to 9Gs to attack targets flying at altitudes ranging from 3m to 30,000m.
Air-to-surface missiles include up to six Kh-29T/L AGM, Kh-31A AShM, Kh-31P ARM, or up to five Kh-59MK longe-range AShM, Kh-58UShE extended range ARM, or up to three Kalibr-A long-range AShM, or one Yakhont heavy long-range AShM. Other air-to-surface weapons include a wide selection of guided bombs as well as unguided bombs and rockets. Laser-guided rockets are also planned to be added to the Su-35's arsenal.
Reference:
MILAVIA Aircraft - Sukhoi Su-35 (Su-27BM) "4++ Generation Flanker"