Dubai Airshow

Sukhoi Su-35 to fly by year-end

 - November 7, 2007, 10:41 AM

Test flights of a completely upgraded Sukhoi Su-35 will start before year-end, according to Sukhoi general director Mikhail Pogosyan. The Russian design bureau (Stand E738) hopes the super-maneuverable multi-role fighter will secure its future in the global fighter market shortly and is promoting it as an interim model between the existing Su-30MK and an advanced fifth-generation aircraft. The company has provisionally slated deliveries for the second half of the next decade.

“The Su-35 is a fourth-plus-plus generation aircraft employing many technologies of the fifth generation,” Pogosyan maintained. “This aircraft is superior to all other foreign fourth-generation fighters. The Su-35 will outperform foreign counterparts and will dominate the world market between 2009 and 2015,” he declared.

The Su-35 is built on a reinforced airframe that promises an extended service life of 6,000 flight hours or 30 years of operation. Aerodynamically, it is similar to the Su-27, but unlike the Su-30MKI, it has no canard fins. To aid the pilot and to improve maneuverability, the company equipped the Su-35 with the new KSU-35 flight control system.

Sukhoi used radar signature reduction technology in the design of the fighter’s airframe, which reduced the amount of reflection in X-band radio waves and at a flight angle of around 60 degrees. The aircraft’s full internal fuel load is 22,352 pounds. It can carry two 475-gallon auxiliary fuel tanks, which increases total fuel supply to 3,777 gallons, and is equipped with a retractable in-flight refueling boom mounted on the left side of the fuselage head.

The Su-35 is powered by two new UMPO/Saturn 117S engines, a considerable improvement over the original Saturn AL-31F turbofan. The engines incorporate new fans, high- and low-pressure turbines, a digital control system and thrust-vector control nozzles. The thrust rating of the 117S has increased to just under 32,000 pounds. In maximum afterburning cold power mode, it reaches 19,400 pounds of thrust. Compared to the AL-31F, the new engine promises at least a twofold improvement in time between overhaul, increasing from 500 to 1,000 hours, with the time before the first overhaul increasing to 1,500 hours and the assigned service life up from 1,500 to 4,000 hours.

The Su-35 is fitted with a fully integrated onboard information management system (IMS) to afford better interaction between crew and all systems and equipment. The IMS includes two central computers, information exchange and processing systems and all-glass displays.

The Su-35 cockpit instrumentation consists of a pair of MFI-35 liquid-crystal, full-color, wide-format displays (nine by 12 inches, 15 inches diagonally and 1,400- by 1,050-pixel resolution); multifunction control unit with an inbuilt display-type processor; IKSh-1M wide-angle head-up display; and control and indication panels.

The first flying prototype of the Su-35 is in the final stage of on-land optimization before test flights, having been demonstrated at August’s MAKS2007 airshow in Moscow. Two more Su-35 prototypes–destined to join the test-flight program in early 2008–are being assembled at the KnAAPO factory (Komsomolsk-on-Amur Aviation Production Association).

The company is also using several Su-27 flying laboratories in the flight trials to prove various systems and the new engines. Series production and customer deliveries of the Su-35 are due to start in 2009. The fighter is already part of Russia’s National Arms Procurement Program, which calls for supplies of Su-35s to the Russian air force through 2015.

Russia’s Rosoboronexport state arms export corporation regards Venezuela, China, Brazil and some Southeast Asia and Middle East countries as potential customers for the Su-35.   

Tikhomirov-designed Radar Is Core of Su-35’s Armament Control

The core of the Su-35 armament control system is an onboard radar with an Irbis-E phased antenna array. Developed by the Tikhomirov Instrument Research Institute, the system is a multifunction radar operating in the X-band and features a passive phased antenna array 900 mm in diameter. It is mounted on a two-stage hydraulic drive unit (for azimuth and roll) and uses a Solo-35 advanced onboard digital computer.

An electronically controlled beam of the antenna array does the scanning in azimuth and elevation at an angle no less than 60 degrees. In addition, a two-stage electric drive mechanically turns the array in azimuth to an angle of up to 60 degrees and in roll to 120 degrees. Therefore, with an electronic control and mechanical corrective turn of the array, the maximum deflection angle of the beam in azimuth increases to 120 degrees.

The Irbis-E radar control system detects and tracks up to 30 aerial targets, retaining the continuity of surveillance and simultaneously engaging up to eight aerial targets. The system detects, acquires and tracks up to four ground targets in several mapping modes with various resolutions at a range of around 220 to 250 miles. In doing so, it continues to survey the airspace.

At a range of up to 250 miles, the Irbis-E system detects, on the head-on course, aerial targets with a cross section of just over 32 sq ft. It can detect super-stealthy targets with a cross section of barely one square foot at a range of up to 55 miles.

The engineering prototypes of the Irbis-E system have passed the required on-bench trials. The company mounted the first of them on the Su-30MK2 No. 503 flying laboratory, where it is undergoing flight tests. It mounted the second Irbis-E unit on the first experimental Su-35 fighter.

Another new element of the Su-35 armament control package is OLS-35 optronics station, which combines a heat-source direction finder, laser rangefinder/ target designator and a TV channel. The station’s surveillance, detection and automatic target tracking zone is around 90 degrees in azimuth and between 60 and 15 degrees in elevation.

The range of detection of an aerial target by a heat-source direction finder in forward hemisphere is no less than 30 miles and 56 miles in the aft hemisphere. The laser rangefinder measures the distance to an aerial target up to 12 miles away and to a ground target up to 20 miles away. The measurement precision is around 16 feet.

For effective operation in an air-to-surface mode, the aircraft can be fitted with a detached optronics pod having a laser/TV sighting unit that detects, tracks, determines the distance to and illuminates ground targets. The unit allows, for instance, the use of laser-guided aerial bombs.

Other new devices among the Su-35 onboard equipment are modern navigation and radio communication systems, systems that enable fighters to operate in groups and a suite of high-performance ECM devices.

In terms of bombing armament and unguided missiles, the Su-35 generally doesn’t differ from today’s Su-30MK. However, in the future it will be able to use both new and improved types of 1,100-pound and 550-pound aerial bombs and missiles of 80-, 122- and 266/420-mm caliber, including some that are laser guided. The maximum combat load of the Su-35 is almost 18,000 pounds, attached to 12 suspension points.