Singapore Air Show

Russian stealth jet takes flight

 - January 31, 2010, 9:08 PM

Years of speculation were brought to an end last Friday with the long-anticipated public debut of Russia’s new Sukhoi T-50 fighter, on the occasion of its first flight. Test pilot Sergey Bogdan took the prototype aircraft aloft for a successful 47-minute maiden voyage from Dzemgi airfield at Komsomolsk-na-Amur, followed by the public release of still and video imagery.

“It is easy and comfortable to pilot,” reported Bogdan. “In the course of the flight we conducted initial evaluation of the aircraft’s controllability, engine performance and primary systems operation. The aircraft retracted and extended the landing gear. The aircraft performed excellently at all flight test points scheduled for today.”

Since winning out over the rival MiG design bureau in April 2002, Sukhoi has been developing the T-50 to answer the Russian air force’s PAK FA (Perspektivnyi Aviatsionnyi Kompleks Frontovoi Aviatsy–Prospective Aircraft System for Frontal Aviation) requirement, which aims to replace the existing Su-27 Flanker with a low-observable air-superiority machine. India joined the program in 2007 and it will participate in the development of the derivative FGFA (fifth-generation fighter aircraft).

T-50 Revealed
Sukhoi has developed and built the T-50 under a veil of secrecy and, despite the publicity of the first flight, little detail has been released. Overall avionics integration is being handled by the Ramenskoye Design Bureau. Elements of the PAK FA, including the Tikhomirov NIIP advanced phased-array antenna (APAA) radar that is intended for the fighter, were shown at Moscow’s MAKS show last August. It has around 1,500 transmit/receive modules and is capable of performing a communications function. Also shown at MAKS were APAA arrays mounted in the wing leading-edge flap sections, which are likely to be incorporated in the PAK FA. Some sources have suggested that the aircraft will also have cheek-mounted, side-looking arrays.

Another system shown at MAKS was the OLS (52Sh) from UOMZ (Ural Optical Machine Plant). This is an advanced infrared/laser complex mounted in a turret ahead of the windscreen that was developed for the Su-35 multi-role fighter, but is expected also to feature in the PAK FA. The T-50 prototype flew with a representative turret fairing installed.

Imagery from the first flight reveals an aircraft that bears some similarities to the Lockheed Martin F-22, especially in its planform and RCS-reducing features, and also to the Northrop YF-23. The T-50 has a chined forward fuselage, with a flattened bottom surface. The thrust-vectoring engines are mounted in trunks that are redolent of the Flanker series, albeit with trapezoidal intakes and some “snaking” to shield the engine faces. Most sources cite NPO Saturn’s 117S (AL-41F) as the
T-50’s powerplant, but a press notice from the company released on the day of the first flight stated that the powerplant is a new design, and that it had completed tests in a flying testbed.

Between the engine trunks is a wide flat surface with two sets of weapon bay doors in tandem, stretching from just aft of the nosewheel nearly to the tail. The bays are thought to be capable of accommodating up to eight Vympel R-77 active-radar missiles, with various air-to-surface options also available.

As befits its low-observable characteristics, armament would normally be carried internally, but marks seen on the underside of the first prototype’s wings suggest the option of fitting up to four external pylons for fuel or weapons carriage. Wing surfaces are similar to those of the F-22, but the T-50 appears also to have moveable sections on the leading edge of the large root extensions. The fins are widely splayed, all-moving, rudderless units.

The mainwheels retract forward into bays on the sides of the engine trunks, outboard of which are angular fairings under the large leading-edge root extensions, which may hold short-range missiles with folding fins.

It is believed that Sukhoi has completed three T-50 prototype airframes, one of which has been delivered to Moscow for ground tests. Assembly is undertaken at the KnAAPO factory in Komsomolsk-na-Amur, located in the Russian Far East. NAPO at Novosibirsk is also involved in the construction.

Around 250 PAK FAs could ultimately be built for the Russian air force, and a similar number of FGFAs for India. Russian Prime Minister Vladimir Putin described the T-50 as a “big step” toward giving Russia an air force fit for the 21st century. He also called for the aircraft to be available for evaluation in 2013, with service entry slated for as early as 2015.