PAK FA, T-50: News #1

I think it is critical that the light 5th gen fighter remain light.

I think they should design it around a 10 ton thrust engine to ensure it doesn't gain weight/expense.

When it reaches operational status fit it with a non AB 10 ton thrust engine and then during its life cycle as it gains weight you can put a 12 ton thrust engine in it to compensate for the growth, but the limitation of a small engine will be the best way to ensure it remains a light fighter.

They don't need two PAK FA aircraft.

The cheaper, lighter, but still 5th gen fighter that is manouverable and stealthy and able to supercruise to about mach 1.5 or so, but also able to carry weapons externally in numbers when stealth is no longer the most important thing.

It should be designed from the point of view of being low cost low maintainence and affordable.

The whole point of having two stealth combatants is that the BVR shots are now denied and the have to come close. A framed canopy can hide a fighter size object as close as 800 meters. I khow, I have flown in a plane.

you think that is not critical for an interceptor ?

But we are not talking about a 4th gen interceptor or dogfighter.

The PAK FA will not have a screen showing radar contacts and a screen showing IRST contacts. Odds are it will have a helmet mounted display showing targets detected by onboard sensors and offboard sensors from other platforms.

The purpose of a frame in a cockpit canopy is that to protect the pilot from bird strikes the canopy needs to be strong enough to resist bird strikes at specific speeds and weights, so it needs x amount of thickness and strength to the front. With a frame you can make the front stronger and thicker while the rest of the canopy can be more optically transparent and much easier to see through.

A frame that is only a few cms across means a small bob up of the head to see one side and bob down will reveal anything behind it... in close combat your IRST will not be affected by the Frame.

BTW cockpit visibility is important for a fighter, but not so important for an interceptor.

Also, the various bits and pieces sticking out.. it is about time these are corrected.

It is a prototype... the sooner they reveal the final shape, the sooner their rivals will be able to develop countermeasures.

Also some things really depend on progress... it doesn't have square engine exhausts because they are still working on them... if they get it right before the aircraft is ready to enter service it might enter service with new square exhausts... otherwise it wont, but that is not to say they wont get them later on.

I think we should keep in mind that this is a defensive aircraft that doesn't need to fly deep into enemy air space and take down an IADS.

It will most likely operate with Su-35s to defend Russian Airspace from stealthy and non stealthy intruders.

That is another good point, as well as being thinner and easier to see through it offers the potential to put det cord in the transparancy so the pilot can eject through the canopy instead of having to wait for it to separate.

The thing I find amusing is that Russian stuff is derided in many parts of the west for just being mindless copiers of western technology, yet when the real products are revealed and are not direct copies of western kit it is criticised.

Perhaps it could be possible that the flying prototypes so far are just prototypes and do no represent the final military aircraft?

The T-50 for the russian requirements may not have to penetrate a highly advanced IADS, but it is meant for export as well, and other customers may well have to.

The exported Su-30MKI and Su-30MKK are quite different from the Su-30M aircraft they are both based upon.

I rather doubt an exported PAK FA will be as stealthy as a domestic model... unless the export customer is prepared to spend money on a stealth technology that the Russians decided not to like UAE did with the Pantsir-S1... just the same as exported F-35s will not be as stealthy as US models.

first we have the debate about the straight through ducts, then the comments about the blockers.. indeed the released patent papers show that the plane is pretty much as it supposed to be.

And what about unreleased patent papers? They are hardly going to release patent papers now that show the PAK FA as it will look in 2020.

The purpose of a prototype is to do full scale tests. When you design something on a computer it is not a real test because it only operates within the parameters set by the software. You really don't know whether your design works till you make it full size and get it into the air. When you fly your first prototypes you don't fit it with everything because if something fails you lose everything... you test specific things with each prototype and as things are proven they are added to the next prototype which adds something else to test.

They currently have three flying prototypes, so they are likely to have tested basic aerodynamics and basic avionics and I believe in the third aircraft they put a main radar in it.

I rather doubt they have even tested thrust vectoring yet, and you think they have the final production aircraft flying around?

Perhaps the plane needs no radar blockers, but the bad press is already being created and look what that press id to the EF2000 and the Rafale.

I really don't think the Russian military care about "press" opinions at the moment. And Sukhoi is hardly going to reveal a state secret just to help its press image.

Very few countries that might buy the PAK FA will base their purchase on press reports. Most will actually test the aircraft before making a decision, and the countries the Russians will sell the aircraft to (in 10 years time perhaps) will be to countries that don't have F-35s as an option anyway... so they can decide on PAK FAs or Su-35s.

Then it is the nozzles. there seems to be no effort in the first few prototypes of a LO approach. Intermediate engines you may say. OK, but potential investors or interested parties to the project can only see what they see.

What potential investors? The Russian government is paying for the development of the PAK FA, and the Indians are paying half for the development of the FFGA.

Any other potential investor just needs to know that there is no European 5th gen fighter, so if they are interested in 5th gen fighters they can go US, China, Russia, Russia/India, or go it alone.

Most of the investors that could join the F-35 program already have (with some regretting it already). The Chinese have a flying prototype, but with Russian 4th gen engines it probably has quite a way to go... which leaves Russia or Russia and India... the latter subject to Indian and Russian approval of course.

The plane has been painted, but not RAM coated still. A curious approach. it makes people nervous. I know because I am nervous.

I would actually say the opposite.... with NATO radars in the Baltic States looking deep into Russia, why would they want to fly around in their new stealth fighter with max stealth and allow NATO a good look at it with radar 2-3 years before it will even start to enter service?

Did the US fly around Russia with their stealth aircraft so Russia could get a good look at the prototypes?

THEY ARE PROTOTYPES... PROTOTYPES HAVE ZERO NEED FOR RAM!

The panels in none of the prototypes have been sawtoothed. and I am not talking about the major panels like landing bay doors, I mean all the little access panels and what have you.

See comment above and replace RAM with Sawtooth edges.

Easy to do on the production line planes people say. NO I say, because you need to evaluate a bunch of things before you make changes like that.

You are entitled to an opinion of course, but you do realise that the final production F-22 aircraft have tape over the panels with ram on that and paint on top of that, so there will be no gaps that need saw tooth edges... just like boards of Gib board don't need sawtooth edges to fit perfectly together under wallpaper, because once you gib them the gaps disappear and what remains is a smooth surface that you wont be able to tell was straight or saw toothed in the first place... It of course means that every time they need to open a panel is a pain in the butt, because they need to remove the paint and ram and tape, open the panel and make the adjustment and then replace the panel and put on the tape and then reapply the RAM and then wait for it to cure and then reapply the paint and wait for that to set... I am sure the Russians are examining other options, but my my my... those silly Americans could have just put saw tooth edges on their access panels and saved themselves lots of time and money... except that saw tooth edges deflect radar signals, but don't decrease them so while it might reduce the direct front on RCS it will massively increase the slightly off bore RCS...

I am afraid that the figure quoted in an obscure website (indian related) that the plane has an RCS of .5m^2 is probably what the intended figure is. ON Average. The frontal RCS of the plane may well be a lot smaller, it may even approach F-35/22 standards, but not all enemies will come from the front and especially stealthy ones. And 0.5m^2 RCS targets can be tracked by existing radars already.

You are comparing average RCS with peak RCS. Besides radars can already track everything... Russian space tracking radars can detect paint chips at ranges of 8,000km. The F-22 and F-35 and B-2 might have RCS of small insects, but how many insects fly at 800km/h or faster at 10,000m.

To put it bluntly the T-50 should have been aiming to have the RCS of a bird. Does it look like the current version is aiming for that? I think not so much.

To put it bluntly you are missing the point.

The F-22 has something like 40 maintainence hours per hour of flight. In real combat where airfields will be targeted it will be a dog. In real combat where there isn't 40 hours for maintainence you will see F-22s operating with RCS of 0.5m or worse.

The prototype you are looking at will be produced in rather larger numbers than 191 airframes and will be supported by S-400 and S-500 missile systems, not to mention Su-35s and possibly Mig-35s, which unlike previous fights the west has been involved in will be using AESA radars and high tech digital EW suites and jammers and fully digital long range AAMs, not to mention with plenty of capacity to reach out and hit those NATO airfields with a range of weapons.

I don't think the PAK FA will be some super powerful all seeing all destroying weapon like the US likes to pretend the F-22 is, but it will certainly be able to do the job and will be a fine compliment to the Mig-31 and Su-35 and Mig-35 and other air defence assets of Russia.

There is no reason for this, even if the engines are a step gap to the final version. The answer is that the rear of the plane is likely to stay as it is. For good.

Of course everything is set in stone... they likely haven't even tested the weapons bay so it will only be armed with a 30mm cannon, because these are serial produced final production aircraft...

Look at a current model F-16 with the external conformal tanks... they weren't added for years after the aircraft entered service. There is no such thing as a design that is set in stone.

Also there is the issue of the sawtooth shape of the weapon bay doors, that is fine, but what is the point if all the other panels don't have them? The gaps in surface will be diffraction points for the radio waves on the other panels except the weapon bays. I find this a bit weird.

See above.

in general I find many things weird. Canopy again being one of them. the frame hides the outside world.

So does the instrument panel... which covers rather more of the outside world than the frame on the canopy.

By having a frame the vast majority of the canopy can be much much thinner and easier to see through, so you can see further.

The PAK FA has 5 radar antennas, and 360 degree IR sensors... do you really think the canopy frame is going to be an issue very often?

Let me repeat... a target that is close enough for the pilot to actually see, or not see because of the canopy frame will be well within the field of view of the front facing radar antenna and IRST.

If the pilot is pulling hard gs then the aircraft is turning... which means the target he is tracking will not remain hidden behind the cockpit frame very long if at all.

ON Average. The frontal RCS of the plane may well be a lot smaller, it may even approach F-35/22 standards, but not all enemies will come from the front and especially stealthy ones.

The fact that you say that the PAK FA will have a RCS of 0.5 on average, but that from some aspects might have a smaller RCS shows you understand the problem. You are comparing the 0.5 average RCS of the PAK FA with the Peak RCS of the F-22 and F-35.

The other point you are missing is that a RCS of 0 will not make the F-22 or F-35 invisible to IRSTs.

More to the point the Russians have rather more experience with thrust vector control engines, which means if both aircraft are so small in RCS that the other side can't get a lock then the fight comes down to IIR guided missiles and cannon fire...

Some say it is a prototype, yes, fine ok, but officials still insist on the 2015 induction to ioc. Surely then the plane currently flying is pretty close to the final configuration.

and it is a configuration that doesn't sell by itself, I am sorry to say I need convincing. ( i know how that sounds)

The RCS wont be known till the final production aircraft comes off the production line in full operational condition.

All that is currently available are estimates.

I have mentioned the law of diminished returns to you in this thread.

Lets just say it will cost $50 million per plane to get a 1 sq m RCS.


It will cost $100 million for a .5msq plane. The problem is that it will cost $250 million for a .1 sq metre plane and probably $10 million per year to operate each one.

The point is that just like the F-16 is a mach 2 plane instead of a Mach 2.5 plane and the F-18 is a mach 1.8 plane instead of a mach 2.5 plane you accept a lower figure in return for an affordable aircraft.

The F-35 in export configuration will not be a B-2 in terms of radar stealth, in fact from the rear it is not very stealthy at all... and because it is not a particularly fast aircraft anyway this is a serious flaw in its design.

US stealth is optimised for X band radar and would not be nearly as effective in other wavelengths... or in IR for that matter.

There is a reason the PAK FA and the Su-35 both have wing mounted L band AESA radars and IRST systems.

A plan doesn't need to be as stealthy as an F-35 to defeat an F-35, it just needs sensors to detect and weapons to kill. IR sensors and IR guided missiles will do the job.

LPI radars are only LPI with old ESM suites that didn't expect radar frequency agile radars with electronic scanning.

Modern ones do and a modern broad band sensor will detect a signal over a wide frequency range.

As I said... not many insects fly at 800km/h at 10,000m and squawk coherent polarised shaped radar beams...