Super Sukhoi – Russia joins the 5th gen club

After a month of taxi tests, the aircraft successfully completed a 47 minute flight during which the landing gear was raised and lowered, and basic manoeuvres and controllability were checked. “This is a great success of both Russian science and design school,” Sukhoi director general Mikhail Pogosyan was reported as saying. “The PAK FA program advances Russian aeronautics, together with allied industries, to an entirely new technological level.

These aircraft, together with upgraded fourth-generation fighters, will define Russian air force potential for the next decades. ” Visually, a virtual ‘walk around’ of the T-50 reveals, on face value at least, that it appears to conform to one of the key definitions of a fifth generation fighter, that is careful shaping and in some areas, detailed design which significantly reduces an aircraft’s radar cross section, ie stealth. And in doing so, the T-50 appears to have borrowed design cues from several existing platforms.

The very wide centre and rear fuselage, or ‘centroplane’ that sees the inner wing and fuselage blended together, as well as the wide empennage and small, all-moving outwardly canted fins are all reminiscent of the Northrop YF-23 concept demonstrator which lost out to the YF-22 in the 1991 Advanced Tactical Fighter (ATF) contest.

The nose and forward fuselage have the now characteristically stealthy chine at mid height, and along with the raised canopy, appears to borrow cues from the F-22, YF-23, F-35 and Sukhoi’s existing Flanker family at various points.

The wings are similar in planform to those of the F-22 but are swept at a sharper 46 degrees, looking almost like swept variable geometry wings in plan, and feature leading and trailing edges aligned with the horizontal stabilisers. The widely spaced engine exhausts are round, three dimensional thrust vectoring nozzles that are similar to those used on the Su-30MKI and Su-35, as is the prominent tail boom which extends out between the engine nozzles. Reports say the T-50 is powered by two NPO Saturn ‘Item 117’ engines of unspecified thrust developed from test engines that have already flown on other Sukhoi testbeds.

The T-50 has two narrow centreline internal weapons bays each said to be capable of carrying two missiles, as well as a smaller weapons bay in each wing root-intake fairing. The large intakes are square in section and feature aligned edges, and the forward blended wingbody join features leading edge wing root extensions (LERX) which appear to be movable to assist in low speed manoeuvring in conjunction with the vectoring engine nozzles.

Initial reports claim a fuselage length for the T-50 of 22m, a wingspan of 14. 2m, and a maximum takeoff weight of 37,000kg, making it about three metres longer than, but similar in weight to, the F-22.

It has a reported service ceiling of 65,000ft, a maximum speed of M2. 44, and will likely be able to supercruise without afterburner at speeds of between M1. 22 and M1. 6.

Taking into account the developmental nature of the T-50, the underside of the rear fuselage and empennage does not appear to have much of the shaping detail as on the F-22 or F-35, with little blending and a few lobe-producing squared off edges and gaps between the fuselage and engine nozzles.

But like the evolution of the YF-22 to the production F-22, there is no doubt much testing and design work to be done to get the T-50 to a production representative state.

Few details have been revealed about the aircraft’s avionics fit, only that it either does or will employ a new large aperture Tikhomirov NIIP advanced phased array radar, and has an aperture on the nose for an infrared search and track (IRST) system. Whether it will conform to another key fifth generation criteria in having highly integrated sensors and other systems such as those of the F-22 and F-35 is yet to be seen, although test avionics fitouts are said already to be flying on other Sukhoi testbeds.

The big questions for the West is how long it will take Russian industry to develop a mature and productionised version of the T-50 for operational service, how quickly the Russian economy can fund this development and an employable production run, and how readily available the PAK-FA will be to foreign customers. Sukhoi says it hopes to be able to field operational PAK-FAs by 2015. n