I do not think the weight of the engine varies, as it affects the center of gravity. All engines AL-31F family have a dry weight of about 1500 kg. Changing engine thrust.

…

For the modernized Su-25 / Su-39 does not make sense to reduce the RCS in tenfold. No internal weapons bays will bring these efforts to naught. Pak Sha will have RCS -1 square meter, without weapons, and about 10 square meters with a weapon.

As I said above, izd.30 will have a capacity 17500 kg / 11000 kg. Its weight must not exceed 1500 kg. This engine can be installed in place of izd.117.
Perhaps it will be equipped with radar-blocker. For the engine developed a new nozzle: vectored thrust, you can enable or disable low visibility, can be thrust reversal.
Technical specifications for the multi-role fighter of the nineties (IFI I-90) called for an engine with variable cycle. In many ways, the PAK FA was designed for this task. Therefore, variable cycle engine for it desirable. This will improve the supersonic cruising speed of M = 1.78 (the engine of the first stage allows you to fly at a speed of M = 1.3 – 1.5).

Is there any available image of that project?

No. The developer proposes pr.21956, but the military found it irrelevant.

Any news on the new CAS type aircraft underdevelopment to replace Su-25 , will this be based on Yak-130 or a entire new design ?

Official sources say the deep modernization of the Su-25. Probably the aircraft will be similar to the Su-39, in the bow – radar, under the fuselage container 101 KS-H. Measures to reduce the visibility. Probably make a new engine, the one that was still on the MiG-21 can not be improved.

Thank you, that is very interesting…

This is speculation.
There’s also two-engine version, but it’s not the optimal solution, especially for the variant with a short takeoff and vertical landing. For a single-engine fighter is no need to create a new engine izd.30 – by that time will be in mass production.
It is known that LMFS compartments will accommodate four air-to-air missiles.

http://paralay.com/lmfs.html

LMFS? Wasn’t it said to be cancelled as all money are focused on T-50? Will LMFS be developed too then? Any idea of the timescale and who is going to build it ? Thanks.

From this great idea will not give up, it can be postponed to a later date.
Multirole fighter superior MiG-29, F-18, Typhoon, Rafale, J-31, J-20 and able to conduct successful combat with the F-35, F-22 and T-50.
It will have great export prospects, especially if the cost of approximately 50% – 60% of the T-50.
Beginning full-scale development of the fighter can be expected after the start of production of T-50, 2015 – 2018. First flight of 2020 – 2023. Series production of 2027 – 2030.
Developer – United Aircraft Corporation (ОАК)

Guys, when will come time for the next russian carrier fighter – successor of MiG-29K/KUB???

T-50K and / or LMFS

Europe today does not make sense maintain large military forces. Greatest challenges now – small operations in the former colonies, the Americans in their imperial desires and restraining each other.
Great War Europe is not threatened. The main character of the European tragedy, at least the last two hundred years, is now occupied by legislative activity in Moscow.