PAK-FA and FGFA Thread

Singha · Post by **Singha** » 21 Mar 2010 22:42

the structure in the photo looks like atleast two layers of visible fixed blocking
vanes ahead of the engine. could be more layers not visible in pic.

serpentine air intake changes the basic design of airframe as placement of
engine has to be close together.

this was not possible to accomodate the rear weapons bay, so they kept
the engines wide apart and went for the f18ish approach.

neerajb · Post by **neerajb** » 21 Mar 2010 23:09

sunnyv wrote:I just hope i am wrong / Or images are a Fanbyoz effort / PS job.

But looks like This is Fan blade indeed. Its a real heart broker.

This is not fan but Inlet Guide Vane (IGV), used to straighten out the swirling airflow to feed the subsequent stage. There are pivot points for each vane at the point where it meets the casing. Even the Kaveri uses fixed and variable IGVs.
Check this image

Cheers....

Austin · Post by **Austin** » 22 Mar 2010 17:40

Ok this is what the Chief Designer of PAK-FA Alexander Davidenko has to say about RCS link

Chief Designer of the aircraft, Alexander Davidenko indirectly hinted at the size of the effective area of scattering (ESR) of the future fighter. According to him, the ESR of the old generation aircraft (eg, Su-27) is about 12 m ², whereas the F-22A Raptor, it varies in the range of 0.3-0.4 m ². EPR PAK FA will not be higher than the F-22A, it will be very close to them. "

If one reads between the lines he says the RCS for PAK-FA will be very close ( but not identical to F-22 ) which considering the fact that Sukhoi has opted for design philosophy of higher maneuverability , he is being honest on what to expect with PAK-FA.

Interesting part is Su-27 RCS is quoted at 12m2 ,which should more or less match the MKI.

PS: Please do not start the next question with but I read somewhere the RCS of F-22 is 0.0001m2 or like a marble, yes that figure is good news for LockMart share holders and its export potential.

Kavu · Post by **Kavu** » 22 Mar 2010 20:18

It is Geometrically impossible for it the Engine's fan blades. I dont think there is a S-Shaped Engine ever produced!
Also the PAK-FA is a fighter with a very long body, and 117 is only 5 meters long, and as you can see, the damn thing is from the nozzle to the inlet is more than 5 meters, double actually.

Please forgive my errors, unlike other BRF members, I am least interested as well as least educated in these technical matters.

Carl_T · Post by **Carl_T** » 22 Mar 2010 21:01

Kavu wrote:
The Frontal Stealth went for a Toss with the IRST, now if this is truely the fan, which I doubt, then we are in for trouble, investing in this product.

How so??

Gaur · Post by **Gaur** » 23 Mar 2010 13:04

^^
I think he is suggesting that the bump in the airframe (because of IRST) would adversely affect the frontal rcs of PAK-FA. I am inclined to agree with him. I remember reading some time back about an incident regarding F-117. When F-117 prototypes were being tested, one prototype was found to have much larger rcs than the others. The engineers searched extensively for the cause of this abnormality. The cause was found to be a single untight screw in the fuselage! So, I would assume a large bump in PAK-FA to have more significant affect on rcs than a single screw. Also the rear and bottom of PAK-FA do not look too stealthy. But if we illiterate abduls can see this, I would assume that the Sukhoi engineers with decades of expertise and experience would know about this too.
This is the reason why many feel that the final version of PAK-FA would be much different than the first prototype that we have seen.

nachiket · Post by **nachiket** » 23 Mar 2010 13:52

Where does the F-22 hide its IRST?

Austin · Post by **Austin** » 23 Mar 2010 14:09

nachiket wrote:Where does the F-22 hide its IRST?

F-22 does not have one , F-35 has something called DAS EO DAS

I think we should stop speculating on PAK-FA RCS considering its Chief Designer made an explicit statement on PAK-FA RCS being very close to F-22.

Unless we are aware of the entire engineering aspect and method adopted by PAK-FA to reduce its RCS , we would end up speculating on the subject and this turns into another keypubs like never ending debate.

sumshyam · Post by **sumshyam** » 23 Mar 2010 14:44

Some blah blah...!

Leaders not impressed by new Russian fighter

The flying debut of Russia’s answer to the F-22 Raptor isn’t wowing Air Force leaders.

Dubbed the T-50 or PAK-FA, the fifth-generation stealth fighter jet made its maiden flight Jan. 29 — 47 minutes over eastern Russia — and has flown at least twice since then. The twin-engine jet will replace the MiG-29 Fulcrum and Su-27 Flanker, both fourth-generation front-line fighters.

The first operational T-50s should be delivered in 2015, the same year the Air Force expects its first F-35 Lightning II. Also a fifth-generation fighter, the F-35 has a single supersonic engine and stealth capabilities.

“I didn’t see anything … that would cause me to rethink plans for the F-22 or F-35,” Air Force Secretary Michael Donley told reporters Feb. 18 at the Air Force Association’s winter conference, held in Orlando, Fla.

“Russia has a robust [aircraft industry],” Donley added. “This is not a surprise in that context.”

The PAK-FA resembles the F-22 — distinctive tilted rear tail fins and all — and has many of the same high-tech features, including digital avionics, a phased-array radar and communications equipment to link the fighter to command and control centers, according to the Russian news agency Tass.

The Air Force ordered the last of its 187 F-22s in 2009. Russia has not had a new fighter in nearly 20 years; the Indian air force is also sponsoring development of a version of the T-50.

“It looks like a plane we’ve seen before,” Gen. Roger Brady, the air boss for NATO and commander of U.S. Air Forces in Europe, said at the conference.

Gen. Gary North, commander of Pacific Air Forces, made clear his impression of the fighter: “I guess the greatest flattery is how much they copy you.”

Still, the four-stars wonder whether the T-50 will live up to its fifth-generation billing.

“I don’t know if it’s really a fifth-generation aircraft,” Brady said. “What I do know is that it’s very clear that they’re working on a fifth-generation technology.”

For Brady, Russia’s push on the development front signals that the U.S. cannot settle for the status quo.

“The key is, we must continue to do fifth-generation and sixth-generation research and put money against it because other people clearly are,” Brady said.

North added that the Pentagon must ensure fourth-generation jets such as the F-15, F-16 and F/A-18 are continually upgraded.

“If we’re not going to buy more, what we’ve got to have is the very best that our sons and daughters go out to fight with,” he said.

In tandem with the T-50 project, Russia is developing a long-range bomber.

“We won’t limit ourselves to just one new model,” Prime Minister Vladimir Putin said March 1. “We must start work on a prospective long-range aircraft, our new strategic bomber.”

D Roy · Post by **D Roy** » 23 Mar 2010 15:02

it is blah blah.

And clearly the headline is a little misleading.

NRao · Post by **NRao** » 23 Mar 2010 17:42

A WOW PAK-FA would be a 6th gen plane. There are a few things that are new (as compared to a US 5th Gen) and that is to be expected, after all the Russians started a full 15 years after. The Russians are capable of greater things, and, if it were not for a bunch of boneheaded decisions in the 90s I am inclined to believe they would be ahead of where they are today.

I would think, based on what is out there, that the FGFA - IF India gets her hands on ALL techs (at good cost no doubt) will be "better" than a PAK-FA. Funds. I for one would think the NMCA/NGFA/MCA would be better than the FGFA - again, the restricting factor would be technologies (and not its applications as in dreaming a design and funding that dream to make it a reality).

Even the production PAK-FA should be "better" than this flying demo model.

I would not compare any of these air crafts from a one-on-one comparison PoV. They will be designed for different needs and therefore will have far different capabilities.

I would leave the compulsion to compare to those down under.

Pratyush · Post by **Pratyush** » 24 Mar 2010 12:46

This who are criticizing the PAK-FA for it not being totally stealthy should note that even the F22 was Modified between its winning the competition against the F23 and the entry into service. We should expect to see the same with the Pak-Fa before its entry into service.

sumshyam · Post by **sumshyam** » 24 Mar 2010 18:47

Some more Information

original

sumshyam · Post by **sumshyam** » 24 Mar 2010 18:49

airflow simulator for radar blocker

http://www.youtube.com/watch?v=SvarEU9oEIY

VishalJ · Post by **VishalJ** » 27 Mar 2010 05:57

Brando · Post by **Brando** » 27 Mar 2010 07:04

NRao wrote: I would think, based on what is out there, that the FGFA - IF India gets her hands on ALL techs (at good cost no doubt) will be "better" than a PAK-FA. Funds. I for one would think the NMCA/NGFA/MCA would be better than the FGFA - again, the restricting factor would be technologies (and not its applications as in dreaming a design and funding that dream to make it a reality).

Even the production PAK-FA should be "better" than this flying demo model.

The FGFA is merely supposed to be a two seater equivalent of the PAK-FA. The Russians would never choose to fly something that is not as good as it gets. Also, as for the MCA, India still lacks a LOT of vital technologies like engines and radars etc. It will be interesting to see if India can build a better fighter with components sourced from around the world than the PAK-FA or the F35 (IMO, it is quite possible in 2020 and beyond! ) .

The production PAK-FA may be more "polished" than the demo model that we have here but so far it is clear to most that the PAK-FA is clearly not technologically superior to the F22. The Russians have yet to develop a mature AESA system where as the Americans have already configured their radars to act as microwave weapons.

The most surprising thing for me about the current PAK-FA is the FLIR sensor that sticks before the cockpit. Since they knew it is going to be standard equipment, why haven't the Russians bothered to have it flush with the contours of the aircraft, instead of creating a region of discontinuity!?

NRao · Post by **NRao** » 27 Mar 2010 08:11

The FGFA is merely supposed to be a two seater equivalent of the PAK-FA. The Russians would never choose to fly something that is not as good as it gets. Also, as for the MCA, India still lacks a LOT of vital technologies like engines and radars etc. It will be interesting to see if India can build a better fighter with components sourced from around the world than the PAK-FA or the F35 (IMO, it is quite possible in 2020 and beyond! ) .

Let us see .....................

"PAK-FA" is a Sukhoi funded effort NOT a Russian funded one.

Russian AF is bankrupt.

On:

India still lacks a LOT of vital technologies like

Please re-read my post. I did qualify it. So, there should not be any confusion on this point.

However, the point I am trying to make is that India has funds, but lacks technologies. My gut feel is that India will catch up on that area for the MCA. Will not be easy (mainly because of denial of techs). And if that is true the MCA will be better (for the IAF) (I hate this stuff about PAK-FA being "better" than the F-22, AFs custom make these planes for heaven's sake).

The production PAK-FA may be more "polished" than the demo model that we have here but so far it is clear to most that the PAK-FA is clearly not technologically superior to the F22. The Russians have yet to develop a mature AESA system where as the Americans have already configured their radars to act as microwave weapons.

I expect it to be different enough to the extent that if they were placed next to each other they would not close to looking alike. Unless, of course, they have no funds and go with "what we have".

The most surprising thing for me about the current PAK-FA is the FLIR sensor that sticks before the cockpit. Since they knew it is going to be standard equipment, why haven't the Russians bothered to have it flush with the contours of the aircraft, instead of creating a region of discontinuity!?

Because it is a tech demo. I read some place that the static one has a better FLIR location and in fact is stream lined.

There are other reasons I bet, the most glaring among all would be "funds". Give them funds and they will produce. Russia has no funds - not to the extent they need to build AND produce top notch planes. Russians CAN do FAR better than this PAK-FA - for there is no lack of brain power there.

Carl_T · Post by **Carl_T** » 27 Mar 2010 09:29

Brando wrote: The Russians have yet to develop a mature AESA system where as the Americans have already configured their radars to act as microwave weapons.

Is the Zhuk radar we are being offered on the Mig-35 not operational/mature yet then?

sumshyam · Post by **sumshyam** » 29 Mar 2010 17:28

Sorry if this has been shared...but it is a good piece..!

http://www.youtube.com/watch?v=KW0x2EDghbE

sunilpatel · Post by **sunilpatel** » 29 Mar 2010 18:09

Carl_T wrote:
Brando wrote: The Russians have yet to develop a mature AESA system where as the Americans have already configured their radars to act as microwave weapons.

Is the Zhuk radar we are being offered on the Mig-35 not operational/mature yet then?

it has to be mature by a great amount...atleast 2200 Trx modules...to compete with amarikans....

other thing is that..... PAK-FA dont have as much stealth feature as f-22, so it needs to have much more powerful Radar to illuminate F-22 before amarikan can illuminate it...

* though, we wont see f-22 v/s Pak-fa but its always better to compare with the best*

nachiket · Post by **nachiket** » 29 Mar 2010 18:13

sunilpatel wrote:
Is the Zhuk radar we are being offered on the Mig-35 not operational/mature yet then?
it has to be mature by a great amount...atleast 2200 Trx modules...to compete with amarikans....

The number of t/r modules (i don't know what "trx" modules are) is limited by the space available in the aircraft nose cone for the radar and also by the backend processing power that is available. You will never have a 2000 t/r module AESA on a Mig-29/35.

NRao · Post by **NRao** » 30 Mar 2010 04:22

sunilpatel wrote: it has to be mature by a great amount...atleast 2200 Trx modules...to compete with amarikans....

"AESA" is not just hardware!!!!!!!!!!!!!!!!!!!

Besides that it has to be "proven".

I am sure everyone will catch-up.

However, I am hoping that the Indians get to build out on their own software - get the hardware from someone else (Complete ToT this time please).

mahesh Sankar · Post by **mahesh Sankar** » 01 Apr 2010 10:08

Check Out the Detailed specification found in the ausi website

http://www.ausairpower.net/APA-2010-01. ... ocId233428

PAK-FA Development History

Early rendering of the PAK-FA design (NPO Saturn).

bodhi · Post by **bodhi** » 01 Apr 2010 10:56

just give the link bro

sumshyam · Post by **sumshyam** » 01 Apr 2010 20:16

Can someone translate it....!

karthik · Post by **karthik** » 01 Apr 2010 22:23

The tail elevator and wing aileron are in the same line! Wont that render the elevator useless?

The aerodynamics of this aircraft is some what revolutionary or just plain weird! If both the wing and elevator are in the same line does it not effect the wind flow to the elevators and make it useless?

geeth · Post by **geeth** » 01 Apr 2010 22:44

>>>If both the wing and elevator are in the same line does it not effect the wind flow to the elevators and make it useless?

How in your opinion, would it affect the wind flow to the elevator???

Viv S · Post by **Viv S** » 01 Apr 2010 23:20

geeth wrote:>>>If both the wing and elevator are in the same line does it not effect the wind flow to the elevators and make it useless?

How in your opinion, would it affect the wind flow to the elevator???

The air flow onto the tail would be diverted by the ailerons. Though since the elevator is pretty large it should still work albeit less efficiently.

^^^I'm just guessing here. I'm sure the Russians have done their homework.

karthik · Post by **karthik** » 01 Apr 2010 23:26

geeth wrote:>>>If both the wing and elevator are in the same line does it not effect the wind flow to the elevators and make it useless?

How in your opinion, would it affect the wind flow to the elevator???

As far as i have seen the flaps and elevators are always aligned differently, either below or above the wing but haven't seen any that share the same flow line. I was wondering if they both share the same flow then it would restrict the flow to the elevator if the flaps are down and eclipse it.

The Su-30 has its elevator far below and the F-4 Phantom has it far above other wise it wont act like two wings and would resemble a delta.

negi · Post by **negi** » 02 Apr 2010 01:01

F-22 too has the tailplane and wings at the same level , imo keeps the frontal RCS in check .

Kanson · Post by **Kanson** » 02 Apr 2010 02:08

The tail elevator and wing aileron are in the same line! Wont that render the elevator useless?

Nope. In this particular case, you see, tailplane acts as an extension of flap. More like 'Fowler flap'(?). IF i'm not wrong, it helps in super cruise and probably reduce rcs.

Indranil · Post by **Indranil** » 02 Apr 2010 02:20

^^^ (previous 3 posts) All the fifth generation fighters at least seem to have inline wings and elevators(may be for lower RCS). F-35, Su-47 (though just a prototype), F-22. Infact the F-18, gripen have them in almost the same line. Almost all planes designed with swept forward wings have the canard, wing and elevator inline. Also notice that even in Su-30 series with canards, the canards are inline with the wings.
It seems obvious that inlining them while cruising would potentially decrease the lift (also drag?). I will however check with my friends in aeronautical studies here and post if it is not. However note that when they are used as control surfaces, they would no longer stay inline, as almost all planes now swivel the complete elevator surface. That brings me to some questions. In modern day fighters, what is the dependence of lift generated by the elevators? Are they used as just stabilizing/control surfaces? Are the chords of the controlling surfaces also inline?
however as Kartik pointed out and AFAIK, civilian/cargo/heavy-lift planes have their wings and elevators skewed. They do depend on the lift from the elevators. one can distinctly notice their meatier aerofoils.

Indranil · Post by **Indranil** » 02 Apr 2010 03:05

Kanson wrote:
The tail elevator and wing aileron are in the same line! Wont that render the elevator useless?
Nope. In this particular case, you see, tailplane acts as an extension of flap. More like 'Fowler flap'(?). IF i'm not wrong, it helps in super cruise and probably reduce rcs.

hmmm. For a fowler flap, the flow is laminar throughout the surface of the wing. In the present case that Kartik is pointing out, there would be a break between the trailing edge of the wing and the leading edge of the elevator. It might be with the supersonic airfoils that these aircrafts employ with flat flaps. what happens once the flaps are down? Laminar flow is certainly disturbed.

Please notice that fowler flaps are used for slow speeds for decreasing stall speeds. But I notice your usage of "like"

rakall · Post by **rakall** » 02 Apr 2010 11:19

karthik wrote:
geeth wrote:>>>If both the wing and elevator are in the same line does it not effect the wind flow to the elevators and make it useless?

How in your opinion, would it affect the wind flow to the elevator???
As far as i have seen the flaps and elevators are always aligned differently, either below or above the wing but haven't seen any that share the same flow line. I was wondering if they both share the same flow then it would restrict the flow to the elevator if the flaps are down and eclipse it.

The Su-30 has its elevator far below and the F-4 Phantom has it far above other wise it wont act like two wings and would resemble a delta.

Actually when the horizontal tail is in a lower plane than the wing -- it is actually in the dirty flow region of wing wake.. this is because the generation of lift by the wing causes a "downwash" -- flow behind the wing tends to go "down"...

In cases where the elevator is below the wing -- it is because of the downwash... which causes increased AOA on the horizontal stabilizer/tail.. so the angle of attach of horizontal tail is set at a reduced AOA (or generally a negative AOA) compared to the wing.. when the horizontal tail in located in the downwash region - it captures the effects of the airplane speed and the consequent "cause-effect" will create stability for the airplane.. (think of a Hansa or such kind of plane which needs stability)

For ex: As speed of the plane decreases, the airspeed over the wing and inturn the downwash at the tail is reduced.. this leads to lower -ve lift at the horizontal tail --> causes aircraft to pitch nose down and lose AOA.. Lower AOA causes lesser drag on the plane and leads to a increase in speed.. which inturn leads to increased downwash --> noseup --> increased AOA...

so placing the horizontal tail in the downwash region (which is actually dirty flow in the wing wake) is to cause stability.. If the horizontal tail is in the same plane as wing -- it will get clean flow.. but will not capture the effects of changing wing AOA, hence no contribution to stability.. but in case of a F22 or PAKFA where it is predominantly flown by FBW computer -- horizontal stabilizer's contribution to stability can be dispensed with..

Kanson · Post by **Kanson** » 02 Apr 2010 11:43

indranilroy wrote:Please notice that fowler flaps are used for slow speeds for decreasing stall speeds. But I notice your usage of "like"

Dear Roy, If you take any primer on anything related to Aero, it tells you that, fowler flaps provides more lift than drag. You take the help of your aeronautics friend and can tell us why elevator is in the same plane wrt wing in F22 why it is above in F-35 and why it is below in F-18...

karthik · Post by **karthik** » 03 Apr 2010 22:03

Actually its the genius of simple out of the box thinking, notice that the leading edge of the Elevator is before the Wing Flaps!!

So this model does not rely on second hand turbulent air from the wing, it scopes the air right below the wing and has its own flow, its simply an "why did they not think of this when they started designing jet plains" sort of thing!

Here is an better view of the elevator to see what i mean. The leading edge of the elevator is actually before the flaps so it does not need to be above or below to catch its own flow. This actually far better.

The question is does the MCA have this and the folks at HAL have realized this too?

PratikDas · Post by **PratikDas** » 03 Apr 2010 22:42

rakall wrote: ....
Actually when the horizontal tail is in a lower plane than the wing -- it is actually in the dirty flow region of wing wake.. this is because the generation of lift by the wing causes a "downwash" -- flow behind the wing tends to go "down"...
....
.. but in case of a F22 or PAKFA where it is predominantly flown by FBW computer -- horizontal stabilizer's contribution to stability can be dispensed with..

Thanks for taking the time to explain this to us aero ignoramuses!

Gaur · Post by **Gaur** » 03 Apr 2010 22:53

rakall,
thanks for the very informative post.

VishalJ · Post by **VishalJ** » 04 Apr 2010 06:55

karthik wrote:

3 Helmets in the cockpit, Nice

Anoop. A. · Post by **Anoop. A.** » 04 Apr 2010 07:28

It's a double trainer(1 instructer + 2 trainee) i guess...........russians have no limits on innovation