Then what makes you think adapting 20 kW irbis would be any easier than having AESA ?

The key thing about Su-57 (and Russia as a whole) that typical western aviation enthusiasts fail to understand is the fact that in the 90’s Russia lost nearly all its “A group” industry. In Soviet terminology: “production of means of production” .

At the moment the problem not in development of something, not in the money it’s required for the production, but in the lack of means of production, in the inability to produce something technically advanced in wide numbers on the modern production line (because of absence of such a lines in Russia).

Irbis was developed in 00’s, but it’s rooted to a late Soviet technology. All the modern stuff developed in Russia could be produced only in limited numbers because a lack of modern machine tools.

So Russia is able to produce Irbis in reasonable numbers, but not the AESA.

A Sabre like engines are very complex design that does not suite well for military jet that would be build in hundreds or even thousands. Carrying oxidizer leads to a lot of drawbacks but a few advantages. If suborbital flight is not required, all related systems is just a dead weight. Oxidizer tanks, pipes, precoolers etc. Also, such a jet would be much larger than a proposed model.

I can see only one possible innovation for a Tempest engine: variable cycle. Like YF120 and AL-41F (initial MiG-1.42’s version). TWR nozzles also, but it’s not an innovation, really.

I am following this topic (and a previous dead too) for quite some time and still failing to get used to this crazy bs some people posts here about Su-57.

Just a little critical thinking is needed to understand few simple things like:

First, PAK FA program has been developing since 2001. About 17 years. Simple comparison with F-22 or F-35 development timelines makes everything clear. Even if Russian designers are as good as the US ones, even if they have as much resources, the jet is being developed for much less time than american fifth generation fighters. So why so much people bashing it? There is no single objective reason to do so. Doing so is as ridiculous as initial Russian plans for PAK-FA program but it’s related to managers and not the designers. It’s also hard to estimate something complex you are not familiar with, like 5th gen fighter.

Second, Russia is not the US. If Russia does something the way unlike the US does, it’s not meant something is wrong. The US military budget is the state property, but development and production companies are private. So they need to negotiate contracts. The government wants pay low, wants service, spare parts etc. The developer wants profit, wants to cover development spendings. In this case bigger long term deals is a win-win solution. Russia is different. Defence companies is 90% state owned. So you can’t create much profit simply put a few bucks from one pocket to another. For Russia it is much more cost efficient to build as few initial design jets as possible. So pointing out that initial batch is only about 12 fighters is absurd.

Third, comparing apples to oranges is really big deal when all you have is a few “telefax grayscale images”. So few objective public data in the net, even about “old” F-22, it’s impossible to make a serious comparison and analysis. Maybe except for a design philosophy and general approach to development. But every “expert” already estimated RCS by photograph devided 0.3m2 by 0.0001m2 and precisely calculates that F-22 is at least 3000 times stealthier than Su-57. “No S-duct = no stealth”, “circular nozzles = no stealth” but how come YF-23 and F-35 are considered quite stealthy fighters? F-35 is stealthiest because of carbon nanotubes, ok. But i wonder how they spotted absence of it on Su-57 pictures? All i want to say is that most of such a statements is just rumors, speculations and nothing more.

Su-57 is very decent fighter. At least it’s very decent design. It’s clearly much more promising and flaws free than F-22/35. The first is expensive, lacks multirole capability, range and some useful systems. The second’s capabilities is compromised by its single engine design. Both are lacking of spacious internal bays. On the other hand, possible Su-57’s flaws like subpar avionics, engines and sysems could be fixed. Even a stealth coating can be improved. Unlike a general design of an airframe.

In the end, i want to appreciate all the people who read through all my poor grammar till this last line.

2.83M is not a maximum speed for MiG-25. It’s just a safe limit. A speeds above that leads to lack of lateral stability and possibility of structural damage (canopy glass). If needed MiG-25 could flight above 3M even with 4 R-60 missiles.

They still have the metal tubes sticking out by the cockpit. Will production aircraft have stealth version of those or not have them and use pressure sensor instead?

I guess no. Russians really does not give much fuk about stealth. So if even F-35 has that tubes, so Su-57 would have them too.

Its most likely the engines.

Indeed. Most of airframe rework was caused by inability to produce an engine wich was planned for Su-27. Delay with the engine was caused by metallurgical institute which fail to create single crystal turbine blades for it in time.

Also, i do not understand why all so obsessed with izd.30. AL-41F1 is quite capable engine. It’s not an alien tech, but it’s on par with F119 in most parameters. At least it’s in top 5 of fighters engines in the world right now. No reason to whine here.

Also, i surprised how many people here don’t understand simple fact that Russian MoD and defence industry is completely different to the US. No reason to use US logic in this case. Government controls MoD and it controls over 90% of defense industry. So no reason to order hundreds or thousands of jets with a goal to cut acquiring price. It’s literally buying from yourself. It’s all about the technology and people employment only. So buying 12 jets clearly means fail in the US, but in Russia it means really noting.