Formerly known as the Su-27M, the Sukhoi Su-35 is an advanced derivative of
the Su-27 "Flanker".  The first Su-27M prototype was displayed at the 1992
Farnborough Air Show.  The Su-35 is expected to enter service in 1995.

Changes from the Su-27 include a new radar, requiring a somewhat larger
nose; foreplanes, as on the naval Su-33; more powerful engines (also
originally developed for the Su-33); an enlarged and improved infrared
search and track unit in front of the cockpit; an infrared missile-warning
scanner on the fuselage spine; numerous internal electronic improvements;
larger tail fins (required by aerodynamic changes imposed by the enlarged
nose); and a large "spine" between the engines containing a rearward-facing
air-to-air radar, allowing the use of rear-firing semi-active radar guided
missiles.  Not present on the prototype, but expected to be on the
production version, are two-dimensional thrust-vectoring engine nozzles (as
on the F-15SMTD demonstrator and YF-22).

The interesting concept of rearward-firing missiles has apparently been
tested on Su-27s, using modified R-73 missiles mounted on rotating pylons
that can fire missiles in either direction.  The production version
apparently has a "nose cone" over the rocket engine (jettisoned on launch),
and modified fins to prevent instability problems while briefly flying
backwards after launch.  The launch rails are fitted with gas cartridges to
boost the missile backwards, so its own engine doesn't have to overcome the
aircraft's full forward speed.  It isn't clear whether the missiles will be
mounted on fixed rearward facing rails, or rotating pylons similar to those
used during development.  How well any of this will work in practice
remains to be seen.

Besides being a better fighter, the Su-35 also has greatly improved ground
attack capability compared to the original Su-27, which was more
specialised for the air-to-air role.

Other Su-27 derivatives include the tandem two-seat Su-30 in interceptor
(Su-30, formerly Su-27PU, intended to supplement the more capable but more
expensive MiG-31) and fighter-bomber (Su-30M, equivalent to the F-15E, and
export Su-30MK) versions; Su-33 (formerly Su-27K) carrier-borne multirole
fighter; and Su-34 (formerly Su-27IB/KU) side-by-side two-seat strike
aircraft (intended to replace the MiG-27, Su-17, and Su-24 in the
interdiction/strike role, probably entering service in 1996).  The Su-30MK
has been offered for export to India and China.  The Su-34 shares the
Su-35's tail radar and rear-firing AAMs.

Vital statistics (Su-35):  length 21.96 m, span 14.70 m, empty weight 18400
kg, normal TO weight 25700 kg, max speed 2440 km/h (Mach 2.30), ferry range
3500 km; power plant:  two 137.30 kN Lyulka AL-31MF augmented turbofans;
armament:  one GSh-30 30mm cannon, 14 hardpoints, max external load 8200
kg.

[My main source here is Steven Zaloga's _Russian Falcons_; thanks also to
Rustam Yusupov for posting additional details]

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--
... Ross Smith (Wellington, New Zealand) <avfaq@meanmach.actrix.gen.nz> ...
"Being in the air farce and navy means you only get to kill people by
remote control, which takes some of the fun out of it."
                                  (Steve Kieffer-Higgins, in alt.tasteless)