Which Sukhoi? The SU-35 Platform
SU-35 ?
As one of our readers noted, DID’s articles from 2005-2007 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, etc. which has been confused with (and possibly redesignated between) the SU-37. So… what do we mean by “SU-35″?
Until very recently, only KnAAPO had listed the SU-35 as a product on its site; Sukhoi now does so as well, but Irkut does not. If this seems confusing, it’s because Sukhoi subcontracts production to affiliate firms – 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.
SU-35 flight, 2008
“…(known as Su-35BM by some sources- ie. T-10BM to the original Su-27s internal T-10S designation). Differences and features largely speak for themselves in the video, but a short summary follows as related in various other sources follows:
1 – N035 Irbis-E PESA (Passive Electronically Scanned Array) Radar, a follow-on to the Bars-M.
2 – No canards
3 – Rear-looking self-defense radar in shorter tail sting
4 – AL-37FU/ 117S thrust-vectoring turbofan engines rated at 142-147kN
5 – Extended high-lift devices with large flaperon occupying the full trailing edge of the wing
6 – L175M Khibiny-M electronic-warfare self-defense system
7 – Reduced-area empennage
8 – Larger Air Intakes
9 – New and lighter systems, including quadruple digital fly-by-wire flight-control system.
10- New man-machine interface with fully-glass cockpit with two large LCD screens and helmet mounted display.”
Movable nozzles
Sukhoi says that the fighter’s structures have been reinforced because of the increased takeoff and landing weight of the aircraft, and the front bearing has 2 wheels for the same reason. Performance is touted as 1,400 km/h (Mach 1.14) at sea-level, and 2,400 km/h (Mach 2.26) at altitude, with a ceiling up to 10 km/ 60,000 feet. Sukhoi has not touted loaded supercruise (Mach 1+, with weapons and without afterburners), which is likely to require improved engines. Thrust vectoring adds new dimensions of maneuverability, however, once pilots understand when to use it and when to avoid it.
The SU-35S will also depend on its sensors. It couples an electronically-scanned array radar with a 2-step electro-hydraulic drive unit, which creates a maximum radar beam deflection angle of 120 degrees. The NIIP Tikhomirov Irbis-E passive phased-array can reportedly detect and tracks up to 30 air targets, simultaneously engaging up to 8. It can also reportedly detect, choose and track up to 4 ground targets, and engage 2. Detection ranges of over 400 km/ 240 miles have been reported for airborne targets, which are the easiest, but resolutions are unspecified. Detecting a 747 passenger jet at 400 km is much easier than detecting a JAS-39 Gripen lightweight fighter, and information about the radar’s resolution would be needed before its real capabilities would be clear.
Full stealth jets like the F-22A Raptor, of course, create drastic reductions in radar detection range that make them a special case. In an emerging age of stealth fighters, therefore, the 80+ km detection range of the SU-35S’ IRST (infra-red search and track) system is very significant.
The SU-30 family has never been especially stealthy, and their overall airframe design limits what one can accomplish in this area. Nevertheless, Sukhoi cites an unspecified amount of “reduced reflectance” for the SU-35 in the X-band, which is a popular choice for modern radars, and in the angle range of plus or minus 60 degrees. Further improvements were made during testing by adding radar-absorbent materials, and removing or modifying protruding sensors that create radar reflection points.
The reported service life of the new aircraft is 6,000 flight hours, with a planned operational life of 30 years. The claimed service life of NPO Saturn 117S thrust-vectoring engines is 4,000 hours. Time will tell.
