Sukhoi's webserver appears to have taken a direct hit.

Any speculations on the insides of the beaver tail and the bulge aft of the cockpit? Construction wise, say use of composites? More of a defensive weapon than the Raptor?

Wouldn't mind an event like this every, oh, three-four years!

B. Bolsøy
Oslo

Aero-geek cyber-attack hits Sukhoi! Yes, I noticed the Firefox thing too...

First impressions....A Ray tracing approach to stealth not having a supercomputer and RCS prediction programmes at hand...

Clearly a VLO design. Shaping appears robust in X band, L band and probably S band in front and side quaters. Facets are large in the order of over 1 meter which satisfy these frequencies.
In the VHF band side on its flat profile should give it very good RCS versus F 22 / F 35 dominated by large if canted tails. Rear quadrant RCs appears disappointing with a clear emphasis on maneouvrability over YF 23 style aft sector facets to which the design clearly has been influenced. Cockpit canopy bow a disappointment but canted. Planform has more lobes than classic 4 lobe YF 23 layout but Lerxes will generate greater maneouvrability at high AOA and ability to dynamically control direction of lerx airflow clearly an innovation intended to work with 3d nozzles and total vehicle management / control surface scheduling system (a technology pioneered in the preceding rival MFI project).

Planform:

Clearly a hybrid between the Yf 22 and the Yf 23 this design appears to combine the best features of both, much as the Su 27 Flanker incorporated the best lessons of the teen generation that preceded it. Wing planform appears F 22 optimised for supercruise but with all moving butterfly tails an attempt to wring out maximum control authority from tails deliberately sized to reduce supercruise drag and side RCS spikes much as the Northrop Grumman McDonnell Douglas JSF contender utilised butterfly tails to reduce weight and reduce tail size increasing range. Overall crossection appears to be YF 23 influenced to presumably take a advantage of volume and RCS advantages inherent to a flatted diamond (in crossection) design. Forward fuselage appears to blend F35 cockpit canopy integration with the Yf 23 moldline presumably to maximise visibility from the upper half of the diamond crossection unlike the F 22 and Yf 23 that seated canopy moldlines far further up.

Operational Factors:

Clearly the Russians sought the range and volumetric advantages inherent of the Northrop design but without the limitations of this design in maneouvrability. Given the size and reputed loadout of 10 missiles, a Yf 23 design would be a logical choice. Likewise in regards to the nose and tail, the T 50 can be seen as an "2010 update" on the YF 23 concept integrating 3D nozzles for maneouvrability at the expense of aft sector RCS, a similar approach to that taken by the F 35 with its circular nozzles (driven by Stovl and weight saving factors). As such like the F 35 a small narrow lobe in the aft RCS sector may exist. Note in the much lauded VHF band this may even be true of the F 22. Other examples of this "update" include some very F 35 reminiscent shaping solutions in the front assembly and a willingness to try the umproven small tail concept proposed by McDonnell Douglas Grumman Northrop in their JSF contender and later X 36 demonstrator. Unwilling to leave the concept of supermaneuvrability we see some curious nods to Russian obsession with post stall combat; namely a moveable lerx lip above the intakes and integration of 3 d nozzles on a 5th generation design, a first.

Conclusion: A very Russian response to the requirements of range, large loadouts and low RCS performance leveraging the many RCS solutions proposed and / or utilised by the U.S.

Excellent (early) analysis Bill, hadn't noticed the outboard bays. Often talked about, only now really implemented.

Martin; the Euro-canards are counting on the Meteor AAM in a very big way, the T-50 may just have burned that ace to ash though.

My impressions are similar to those above. I wouldn't put this into an "all aspect VLO" design that the F-22 and to a lesser extent the F-35 are, but rather an advanced pac-man design if you will. This clearly being a prototype we'll have to wait to see what a production bird will look like but there are some shaping features which suggest a smaller frequency response compared to the spared-no-expense ATF designs. For instance beyond the previously mentioned IRST aperture and aft fuselage, the inlet and center body are not flat and in fact have nearly vertical and round shaping features which would provide for strong specular returns at even high frequencies. I suspect that the frontal signature will be in the F-35 ball park, perhaps, but will not match the Lightning in all aspect signature. I don't think it comes close the F-22 in any aspect at any frequency.

I'm a bit skeptical with some of the basic specifications such as weight and range. I've heard in the Su-27 weight range but I'm very skeptical of that. It very similar in size but larger in volume and because it has two large ventral and two lateral bays it will certainly pay a weight penalty over its forbearer; there's an old axiom in aircraft design: holes are heavy. I suspect it'll be similar in weight to the SU-35BM; i.e. about 41,000lbs or so. I dont think it will carry much more fuel either. Those ventral bays will take up most of the extra space gained over the Su-27 series so I suspect it'll be in the 20,000lb region; granted more than the F-22 or at least what the F-22 is cleared to carry.

Overall looks like a good jet for what the Russians need, but it clearly wasn't designed with the same emphasis as a deep IADS penetrator that the ATF requirement called for. A formidable jet I'm sure, but I just don't think signature management was as high on the list for the Russians as it is for the US.