PAK-FA and FGFA Thread

shukla · Post by **shukla** » 16 Mar 2010 19:13

Official version of joint development of FGFA..

/LOK SABHA/

India and Russia signed Inter Governmental Agreements (IGA) for Co-development and Co-Production for Multi Role Transport Aircraft (MTA) on November 12, 2007 and for a Prospective Multi Role Fighter Aircraft (PMF) on October 18, 2007.

The percentage share of investment by the Indian side towards development will be 50 % each for both aircraft. The Fifth Generation Fighter Aircraft (FGFA) would be comparable to the best of its type/class in the world. The project would be set up in India, as well as in Russia. MTA & FGFA, both are design and development programmes. It is estimated that the aircraft would be inducted by the Indian Air Force in the 13th Plan period.

This information was given by Minister of State for Defence Shri MM Pallam Raju in a written reply to Shri Tufani Saroj in Lok Sabha today.

http://pib.nic.in/release/release.asp?relid=59623

Brando · Post by **Brando** » 17 Mar 2010 01:08

sumshyam wrote: I think, trying to not to part with technology and shear arrogance and extreme of a paranoia.

How so ? The US has seen time and time again the effects of technology proliferation to countries like China, Iran etc that have harmed its interests. Also, calling caution as "paranoia" is unwarranted. Will India sell its ballistic missile technologies to say, Bangladesh or Nepal or even some african country for cash ? There are some other considerations that need to be taken like what effect such technologies might have to that region, how responsible are the countries that are going get such technologies and what is the long term outlook for global peace.

sumshyam wrote: As you said, Americans shared some of their technology with Europeans...to counter Russians...It itself can be considered an effort to dilute contemporary USSR military capability.

And yes, even if in the era of cold war, Russian shared a greater degree of co-operations.

You are correct Russia did share more technologies but it never shared MIRV or SLBM technology with India either! The Americans have shared a LOT of civilian technology with the rest of the world, something the Soviets always lacked. Even today many many technologies are not shared by Russia. This is natural and to be expected. Those who own the technology are not willing to share it because, technology is power.

sumshyam wrote: Yes, Americans are superior in terms of technology on this very day....but it is not their parental property....and I think this is the bottom line...!

I don't understand your meaning. Are you trying to say that they don't have the right to their own technology that they have developed ? It is their parental property most literally. All these technologies have been developed by American scientists in American labs paid for by the American taxpayer during the Cold war. How can you claim that they don't have a right to it ? Naturally as the owners, they can sell it to whom ever they want or not. Same goes with the PAK-FA. The Russians might not wish to sell them to some and not sell it to others. It is their property.

sumshyam wrote: And Yes, the talk was not for the trend of US military co-operations...but was for friend considerations and mutual respect for the partners...and Russians win it...without a doubt.

Here again I completely disagree. Show me one instance where Russia helped an ally as profoundly as the US help to Great Britain during World War 2 ?? Or how Kuwait and Saudi Arabia were helped by the US to take down Saddam during GW1 ? Take a look at US allies and you can see the level of industrial and economic development they have. Even their former enemies like Japan, were rebuilt through American cooperation. Forget about India and Pakistan but take a look at the rest of the world. Which countries do Russians call "friend" ? I don't think many countries fall under that category. In fact, it was America that helped the Russians build fighters during World War 2.

sumshyam · Post by **sumshyam** » 17 Mar 2010 06:18

Brando wrote:
sumshyam wrote: Yes, Americans are superior in terms of technology on this very day....but it is not their parental property....and I think this is the bottom line...!
I don't understand your meaning. Are you trying to say that they don't have the right to their own technology that they have developed ?

Show me one instance where Russia helped an ally as profoundly as the US help to Great Britain during World War 2 ??

Forget about India and Pakistan but take a look at the rest of the world. it was America that helped the Russians build fighters during World War 2.

Well, I never questioned their copy right over their self developed technology...I just said that the lead as of now they have, is not their parental property....they will loose it for certain...!

well, lots of examples....anyhow one of them is our war of 1972...chasing Enterprises war did it...didn't it...!

Nope...Its only us..and we don't look to see what other have to say and do.

Americans helped Russians to build air crafts....I am laughing..!

sumshyam · Post by **sumshyam** » 17 Mar 2010 06:19

Interview about engines of the NPO Saturn

Translated

Original

Brando · Post by **Brando** » 17 Mar 2010 06:51

sumshyam wrote: Well, I never questioned their copy right over their self developed technology...I just said that the lead as of now they have, is not their parental property....they will loose it for certain...!

well, lots of examples....anyhow one of them is our war of 1972...chasing Enterprises war did it...didn't it...!

Nope...Its only us..and we don't look to see what other have to say and do.

Americans helped Russians to build air crafts....I am laughing..!

America may loose its technological lead but not anytime soon. They have carefully built their advantage through work and intelligence. India talking about "parental property" is just like Somalia talking about India's IT prowess and asking the same question.

It is absurd to compare the presence of a couple of Soviet subs to the hundreds of millions of dollars and men in aid that the US spent on its friends and allies during World War 2.

As to the American help to the Russians see the P-39 (more than 4000 of these were sent to Stalin till they could build the Yak-9s ) .

andy B · Post by **andy B** » 18 Mar 2010 17:06

The latest Air International has an article on bad boy Pak Fa some pointers:

- Oval shaped antenna of the SH121 in current form is about 900mm wide and 700mm in height and contains 1526 T/R modules; the final antenna for Pak Fa will reportedly be larger and contain about 2000 modules

Tests for the new radar are supposedly starting in 2010 using a Tu134 (same jet used to train Blackjack crews). Five AESA antennas front Xband, two located on the side are also X band and two installed in wing leading edges are L band.

- Currently two AL-41F1 (izdeliye 117 - advanced version of AL41-F1S - izdeliye 117s used by Su35) rated at 147kn each.
It suggests that final versions or later versions will be powered by a new engine with >157kn

thrust each.

- Tender for 2nd stage of engine was issued in 06 but cancelled in may 07. Proposals by both NPO Saturn and MMPP Salut were rejected due to "formal" reasons. According to Ilya Fedorov (GM of Saturn) the date contest has been moved to the first quarter of this year, but that does not mean necessarily that it will not be postponed again. Fedorov expects that the project will be carried out with co-operation of several companies led by Saturn:
- Core - Aviadvigatel in Perm together will Saturn will work on Core
- NPP Motor in Ulfa would make low pressure compressor fans and afterburner chamber
- Klimov in St Petersburg would make the TVC nozzle, gearbox and APU
- AMNTK Soyuz in Moscow will look after inlet guide vanes as well as rcs reduction for injun
- Series prod. for new engine likely to happen at UMPO Factory in UFA where 117 and 117s are manufactured
NPO Saturn is currenly offering participation to its greatest rival MMPP Salut (Moscow based), however Salut is expecting more as it wants to be a general integrator. Salut has lost the 1st stage injun tender and is continuing development of the AL-31 FM3 in hopes of powering the PAK FA rated at 152 kn.

- Engine TVC supposedly managed the same way as the MKI the nozzles move up and down (two dimensional) but the central plane of each nozzle is deflected aside (right to right and left to left) so the nozzles move within v-like intersecting planes. Inclusion of LEREXes a very important feature.

- There are quite a few pics of missiles(AA and AG) all with complete folding fins notable are 810 type AA missiles (4.2m or 13.9 ft) long range, multipurpose KH 38M (4.2m or 13.9ft) long weighing 520kg (1146lb) and KH58 USHK (4.2m or 13.9ft) long weighing 650kg anti radar missile. Each weapons bay reportedly are estimated to be 4.6m to 4.7m (15.1 to 15.5 ft long) and 1 to 1.1 m wide (3.3ft to 3.7ft) two 810 or KH38M or KH58USHK can be placed inside one weapon bay. Other smaller types of munitions include K77M, K74 and K30. Also KH36 anti radar and 250KG and 500KG guided PGMs. A single but similar weapon bay was fitted to the Berkut in summer of 07 this had two ejector racks and side by side placement.

- Static instability is reportedly 10% to 12% when compared to the 5% to 6% of SU27M/MKI and the neutral instability of basic SU27. Design aimed towards being more agile when supersonic than previous fighters.

Austin · Post by **Austin** » 18 Mar 2010 17:25

^^ Great Thanks , The ~2000 T/R module is interesting , Considering they are working on new gen Ga/N module that would provide far greater capability then the present ~ 1500 Ga/A T/R module.

Can gurus explain this in simple english

Static instability is reportedly 10% to 12% when compared to the 5% to 6% of SU27M/MKI and the neutral instability of basic SU27. Design aimed towards being more agile when supersonic than previous fighters.

VishalJ · Post by **VishalJ** » 18 Mar 2010 22:16

I'm not sure if this has been posted/asked before but, I came across this photo, is something like this with foldable wings planned for IN or just some more fan-art ?

NRao · Post by **NRao** » 19 Mar 2010 02:17

Initially there was only talk of a dual seater FGFA. Now we have a bunch of single seaters too. Wonder if some or all these single seaters are meant for the IN.

andy B · Post by **andy B** » 19 Mar 2010 03:50

Austin saar me no aero injuneer.

Moi simple paki brain follows the below statements:
"An aircraft with static instability uniformly departs from
an equilibrium condition"

"An aircraft with dynamic instability oscillates about the
equilibrium condition with increasing amplitude."
www.grc.nasa.gov/WWW/K-12/airplane/FlightControl.ppt

So I think it means that ze pak fa has static instability but I dont understand the percentages, as in 10 to 12% of what the whole design?

NRao · Post by **NRao** » 19 Mar 2010 04:39

Andy,

Your deliberate misspelling of words will be picked up as-is by bots and will never be search-able. Your post/s contain very good points, points or information that will never be disseminated to others (who may be looking for it).

(Also, it makes it more challenging to read and make sense.)

andy B · Post by **andy B** » 19 Mar 2010 05:29

NRao wrote:Andy,

Your deliberate misspelling of words will be picked up as-is by bots and will never be search-able. Your post/s contain very good points, points or information that will never be disseminated to others (who may be looking for it).

(Also, it makes it more challenging to read and make sense.)

Wokay I will post some stuff that I collected some time back from Google maharaj Jai Ho:

- I think it is important to understand stability first (what makes a plane stable) before jumping to how a plane is statically instable.

Stability:
- "Stability is the tendency, or lack of it, of an airplane to fly a prescribed flight course."
- "For an airplane to be in equilibrium for a particular flight course, the sum of all the forces and moments on it must be zero. (A moment is a measure of the body's tendency to turn about its center of gravity.) Lift equals weight, thrust equals drag, and there are no net rotating moments acting on it. It is in equilibrium.'

-"Now, if the airplane is disturbed, for example, by atmospheric turbulence, and noses up slightly (angle of attack increases), the airplane is no longer in equilibrium. If the new forces and moments, caused by the angle-of-attack increase, produce a tendency to nose up still further, the airplane is statically unstable and its motion will diverge from equilibrium. If the initial tendency of the airplane is to hold the disturbed position, the airplane has neutral static stability. On the other hand, if restoring forces and moments are generated by the airplane that tend initially to bring it back to its equilibrium straight and level condition, it is statically stable."

- "If it is assumed that the airplane is statically stable, it may undergo three forms of motion with time. (1) It may nose down, overshoot, nose-up, overshoot to a smaller degree, and eventually return to its former equilibrium condition of straight and level flight. This type of decaying oscillatory motion indicates that the airplane is dynamically stable. (2) It may continue to nose up and down thereafter at a constant amplitude. The airplane is said to have neutral dynamic stability. Or, in the worst case, (3) it may nose up and down with increasing magnitude and be dynamically unstable."

Thus we can say that an Aircraft that has static stability will always tend to return to level and straight flight even though it may go through the motions of nose up, nose down, overshoot (smaller and greater degrees) in time.
http://www.centennialofflight.gov/essay ... y/TH26.htm
http://www.synchrolite.com/B326.html
http://aircraft-license.com/Demo/8.4.pdf
http://desktop.aero/appliedaero/configu ... ility.html

In summary I think the 10% to 12% measure of static instability may be that ze Pak Fa is that mucho more as compared to neutral instability of the basic 27. So I guess the 27 would never have been able to fly in a straight line without constantly manupalating its control surfaces to achieve level flight. So it may be 10 to 12% more than the basic 27.

andy B · Post by **andy B** » 19 Mar 2010 06:24

NRao wrote:Andy,

Your deliberate misspelling of words will be picked up as-is by bots and will never be search-able. Your post/s contain very good points, points or information that will never be disseminated to others (who may be looking for it).

(Also, it makes it more challenging to read and make sense.)

Saar,

I got into that habit bcoz of Ncubus Maximus after following through on his nefarious Airbus and yindoo Lca discussions with Vina saar...

Ncubus ji if joo are reading this please come back....

negi · Post by **negi** » 19 Mar 2010 06:49

Austin wrote: Static instability is reportedly 10% to 12% when compared to the 5% to 6% of SU27M/MKI and the neutral instability of basic SU27. Design aimed towards being more agile when supersonic than previous fighters.

Austin afaik it translates to "faster stick response" plain and simple , which is a desirable feature during high 'g' maneuvers , if I were to hazard a guess we might see a Rafale/F-16 like HOTAS mounted besides the arm rest i.e. a departure from conventional layout.

Pratik_S · Post by **Pratik_S** » 19 Mar 2010 10:58

Don't know if you have seen it before or not, here are the images of PAK-FA in camouflage.
Angle of Attack

Igorr · Post by **Igorr** » 21 Mar 2010 02:38

Indeed were taken from these: 1 2 3

andy B · Post by **andy B** » 21 Mar 2010 05:58

Ze Pak Fa article from Air International March 2010 Enjoy...AOA

http://ifile.it/04cejp9/PAK%20FA.zip

Craig Alpert · Post by **Craig Alpert** » 21 Mar 2010 06:29

andy B wrote:Ze Pak Fa article from Air International March 2010 Enjoy...AOA

http://ifile.it/04cejp9/PAK%20FA.zip

So one thing is crystal clear from this article, that PAK-FA will NOT have a rear facing radar

It would be interesting if they change their minds, and accommodate these somewhere down the road!

andy B · Post by **andy B** » 21 Mar 2010 06:42

Craig Alpert wrote:
andy B wrote:Ze Pak Fa article from Air International March 2010 Enjoy...AOA

http://ifile.it/04cejp9/PAK%20FA.zip
So one thing is crystal clear from this article, that PAK-FA will NOT have a rear facing radar It would be interesting if they change their minds, and accommodate these somewhere down the road!

I personally would not discount that at this stage....the Pak Fa right now is like Sachin when he debuted, he caused a massive stir...but as he matured the ripples grew bigger

Let us wait and watch for you may never know where the Devil is hiding...until its too late...

I personally do not think the rear ward facing radar is such a big deal, I mean how many jets are gonna be able to get into a 3, 6, or 9 o'clock position against this baby hain?

Austin · Post by **Austin** » 21 Mar 2010 10:54

negi wrote:[Austin afaik it translates to "faster stick response" plain and simple , which is a desirable feature during high 'g' maneuvers ,

Ah you made it that simple ,Thanks

AndyB Thanks a ton

negi · Post by **negi** » 21 Mar 2010 11:00

Austin bro , that was my interpretation of the whole idea behind need to go for increased instability , of course possible due to more capable FCS.

Btw what is your take on speculations around rear facing radar on PAKFA ?

Austin · Post by **Austin** » 21 Mar 2010 16:27

negi wrote:Austin bro , that was my interpretation of the whole idea behind need to go for increased instability , of course possible due to more capable FCS.

I mean your explanation was straight forward and simple to make a layman like me understand it.

Btw what is your take on speculations around rear facing radar on PAKFA ?

Well yes they will have a rearward facing radar for sure , most likely a X band AESA type , if nothing else they would compliment the MAWS and give better situational awareness to the pilot.

Since they are planning to operate number of radar on the PAK-FA ( X,K,L ) plus IRST , the sensor fusion part would be interesting if they get it right.

The latest AFM issue has Rafale bragging about Sensor Fusion and its duel with F-22 and Eurofighter , seems like Rafale is no babe in the woods to use Santys term.

Kavu · Post by **Kavu** » 21 Mar 2010 18:57

http://img692.imageshack.us/i/pakfafront.jpg/

This opens a can of worms, Though Personally I dont think they are fans, if you look closely they seem static,and even welded

Rahul M · Post by **Rahul M** » 21 Mar 2010 19:00

^^^ similar to the super-hornet's engine-face blocker. (whatever it is called)

Kavu · Post by **Kavu** » 21 Mar 2010 19:06

Rahul M wrote:^^^ similar to the super-hornet's engine-face blocker. (whatever it is called)

They are way too close to inlet opening for it be the real fan, if one takes the length of the AL Engine and the length of the PAK-FA, from the back, it is quite clear, the engine would reach somewhere in middle, not anywhere close as shown, This something else, There is so much shaping behind that air intakes, not to mention hard work, for it be something as idiotic as straight up fan visibility.

sumshyam · Post by **sumshyam** » 21 Mar 2010 19:10

Perhaps very very disappointing....all the talk and claims about S shape air inlet are worthless as per the following picture...and forget about stealth...!

Kavu · Post by **Kavu** » 21 Mar 2010 19:14

sumshyam wrote:Perhaps very very disappointing....all the talk and claims about S shape air inlet are worthless as per the following picture...and forget about stealth...!

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.

sumshyam · Post by **sumshyam** » 21 Mar 2010 19:18

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.

Don't know about IRST....but this definitely killed it for me....provided photo is original...what the heck...Russians can't even design a S shape diffuser in a decade...!

Singha · Post by **Singha** » 21 Mar 2010 19:23

Nook nood - again

Karan M · Post by **Karan M** » 21 Mar 2010 19:57

They appear to the the F/A-18 E/F approach.

The F/A-18 E/F has radar blockers (appear similar to the form of inlet blades) placed well ahead of the intakes.

The F/A-18 E/F (clean) RCS is stated to be superior to the E/F Typhoon and other European aircraft.

PAK FA has edge alignment as well, which should help more.

Karan M · Post by **Karan M** » 21 Mar 2010 20:03

F/A-18 E/F Radar Blocker

Rahul M · Post by **Rahul M** » 21 Mar 2010 20:09

sumshyam wrote:
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.
Don't know about IRST....but this definitely killed it for me....provided photo is original...what the heck...Russians can't even design a S shape diffuser in a decade...!

this is certainly NOT the fan.

Craig Alpert · Post by **Craig Alpert** » 21 Mar 2010 21:30

If one were to look @ the pics, some conclusions can be based. 1) Engine not in-line with the blocker. 2)Use of a blocker along with semi-lateral/vertical duct and engine toe-in. and 3) We now know where the MLG goes

sunnyv · Post by **sunnyv** » 21 Mar 2010 21:44

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.
http://img692.imageshack.us/img692/8483/pakfafront.jpg
[center]

[/center]

May be in future lets hope they change intakes to a more curved ones at-least -
pic below is 117s which is not final engine .

Rahul M · Post by **Rahul M** » 21 Mar 2010 21:47

rest easy it's not the fan blades !

fan blades aren't welded to the insides of the intake walls.

Karan M · Post by **Karan M** » 21 Mar 2010 21:54

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

Again, how do you know this is a fan blade and not a radar blocker?

What visual differences can you find between a radar blocker and a fan blade?

Apply some logic to this issue as well.

1. The engine is not directly aligned to the inlet so how can these blades be directly aligned?

2. Also, the engine is located partially above the line of view of the inlets, so how can these blades be located towards the lower part of the inlet and be fully visible.

3. Why would fan blades be welded to the intake sides?

Common sense suggestion is that the Russians want to be on the safe side and ensure a reliable and maintenance friendly way to ensure no radar signals are reflected out of inlet, which may have bottom 10-15% of engines visible from some angles at lower elevation (see manner in which engines are dispalced horizontally and also displaced vertically). Even if engines are fully displaced within, the issue is whether to go through all the modeling to be 100% sure no radar energy is reflected out.

Otherwise one has to constantly test entire way through serpentine intake with specialized equipment and make sure everything, including RAM is spec.

Putting a radar blocker up front is simple, and less of hassle.

Engine is also not the 117S but 117.

Karan M · Post by **Karan M** » 21 Mar 2010 22:06

Radar Blockers:

Aviation Week & Space Technology

Stealth Engine Advances Revealed in JSF Designs, 03/19/2001

DAVID A. FULGHUM/ORLANDO, FLA. and WASHINGTON

"Radar blockers" or "stealth intake devices"have been developed for Boeing's F/A-18E/F and F-22 and are even being improved on the former aircraft. The difference is that the blocker is a separate device on Super Hornet, while it is an integral part of the engine, at least in the Boeing version of the JSF. The F-22 and Super Hornet use a combination of curved inlets and radar blocker technologies.

The first-generation SR-71 used huge inlet spikes to control radar reflections. The second-generation F-117 uses a more primitive grid device over the inlet as a radar blocker. A finer mesh screen was used on Northrop's Have Blue proposal, which would have choked air flow and limited top speed to about Mach 0.65. (AW&ST Feb. 10, 1992, p. 23). These earlier designs were abandoned in response to the demand for supersonic strike aircraft and cheaper, more robust stealth. Keeping radar beams out of the engine is a particular concern for aircraft with a single, large engine inlet.

The F-117's inlet screens, when aligned with the rest of the aircraft's external faceting, help create uniformly conducting electrical surfaces that allow radar waves to flow around the stealth aircraft and exit from its aft-most point. Some stealth specialists worry that these signals, emitted to the rear of the aircraft, could provide the basis for a counter-stealth defense system.

The Boeing JSF's intake radar blocker is built as part of the face of the engine with a bullet-like centerpiece surrounded by angled, radiating vanes. In parallel, the US has developed infrared and radar suppression devices for jet exhausts and these have been flying on stealth aircraft for a number of years. These two types of blockers are generally used in conjunction with one another and the latter has become increasingly sophisticated as researchers find better ways to deal with an environment of extreme exhaust heat.

"We've been using blockers in aircraft exhausts for many years," said a senior aerospace official. "It doesn't significantly affect the engine's airflow [which translates to power] through the exhaust, but [when used in an inlet, a blocker] has the potential to restrict airflow into the engine."

Some stealth specialists say the loss in engine efficiency when using a blocker would be limited to only a few percent, and may be offset by the greater efficiency of a single large engine inlet (Boeing's option) compared to two smaller inlets (Lockheed Martin's design). Others say the effects of a blocker inside an inlet are more pernicious.

"It's physically easier and more robust to build a long, serpentine duct and hide the [engine face], compared to the difficulties of putting in a [blocker] device," said a second stealth specialist with insight into the JSF program. "You've added something else that scatters [radar energy]. You also have to account for the demand on power and subsystems. For example, you have to deice the [blocker] element.

"[Total engine efficiency] depends on the design of the device, the duct, the lips and how the pressure recovery and bleed systems are operating," the second specialist said. "It's fair to say there will be a performance loss when there isn'ta nice, shallow, smooth duct. Finally, having something out there that can be hit by a bird or runway debris is not good [for maintaining the stealth signature]."

Lockheed Martin's JSF design has room for the long, spiraling duct because the engine is located well aft in the aircraft. A shaft transfers power from the engine to a lift fan located just behind the cockpit to permit short takeoff and vertical landings (STOVL).

However, Boeing's JSF demonstrator is designed for direct thrust from the engine to provide its STOVL capability. The engineering demands of the system required the engine to be much farther forward in the fuselage, allowing only enough room to hide the upper half of the engine face. Instead, Boeing is using a radar blocker built into the engine's face. The Super Hornet design differs in that it combines slightly curved inlets with a blocking device ahead of and separate from the engine face.

ADVOCATES OF THE BOEING design say new technology makes the short inlet a better bet. "The issue is purely one of how much distance is involved in dealing with the [radar] energy," said an aerospace industry official with long experience in the JSF competition. "While the longer inlets are generally easier to model [and build], they consume a lot of internal volume in the aircraft and often produce aerodynamic or maintenance challenges."

Stealth specialists agree that the choice of longer serpentine ducts versus larger radar blockers is a tradeoff between stealth, cost and aerodynamic performance. In smaller aircraft, the serpentine ducts tend to integrate better "than a big, fat single inlet," said a Northrop Grumman official. But when a larger aircraft is involved, it sometimes becomes more efficient to rely on a larger blocker, he said. There is also the issue of price.

"Anytime you have a [large, complex inlet] front frame, it's more expensive from the aspect of construction and integration costs," the official said. "I know the front frame of the F/A-18 represents a significant development cost. Certainly the inlets on Pegasus [a new unmanned combat air vehicle demonstrator] are one of the most challenging aspects of the aircraft's integration."

It is known that the radar-blocking devices have helped reduce the F/A-18E/F Super Hornet's radar cross section (RCS) to an unprecedented low for non-stealthy aircraft--around 0 dBsm., the equivalent of about a 3-ft.-dia. aluminum ball. That is far smaller than other aircraft that did not start out as stealth designs. By comparison, a human has an RCS of about -10 dBsm.; the JSF, designed from the start for low observability, is to have a stealth signature of -30 dBsm. (about the reflection from a golf ball); and the B-2/F-22 are pegged at -40 dBsm. (about the size of a marble).

PAK FA is meant to be conscious effort for "affordable stealth" and with edge alignment and internal weapons should do well enough.

Samay · Post by **Samay** » 21 Mar 2010 22:16

AFAIK. There was an article ( karlo kopp?) it stated that russians would be using radar screen or s-shape duct, it looks they have used a screen .
That certainly doesnt looks like frontal blades of the engine.

BTW there are so many patches of radar absorbing material on the pakfa,it seems there is a lot of integration left to be done, what is lesser known is that whether ruskies will be changing inlet shape or not?

sunnyv · Post by **sunnyv** » 21 Mar 2010 22:31

Mrinal wrote:"But looks like This is Fan blade indeed. Its a real heart broker."

Again, how do you know this is a fan blade and not a radar blocker?

What visual differences can you find between a radar blocker and a fan blade?

Apply some logic to this issue as well.

1. The engine is not directly aligned to the inlet so how can these blades be directly aligned?

2. Also, the engine is located partially above the line of view of the inlets, so how can these blades be located towards the lower part of the inlet and be fully visible.

3. Why would fan blades be welded to the intake sides?

Common sense suggestion is that the Russians want to be on the safe side and ensure a reliable and maintenance friendly way to ensure no radar signals are reflected out of inlet, which may have bottom 10-15% of engines visible from some angles at lower elevation (see manner in which engines are dispalced horizontally and also displaced vertically). Even if engines are fully displaced within, the issue is whether to go through all the modeling to be 100% sure no radar energy is reflected out.

Otherwise one has to constantly test entire way through serpentine intake with specialized equipment and make sure everything, including RAM is spec.

Putting a radar blocker up front is simple, and less of hassle.

Engine is also not the 117S but 117.

Pic is 117s , i googled Images.
How can we be sure its definitely not engine blades, Pic i posted of engine and above image looks same on frontal side.
Rest all about S- shaped intakes were all speculation i guess , just typical CARLO KOPP like.

I myself hope i am wrong but at this stage i am gonna cry

Karan M · Post by **Karan M** » 21 Mar 2010 22:40

Why dont you read the articles posted before crying?

Also, apply your own common sense. You have two eyes and the post tells you what to look for. The engines are not in line with the inlet, so those cannot be fan blades. They are displaced horizontally and vertically from the line of sight of the inlets.

They may be using both S Shaped inlets and radar blockers like the F-22 (Article above).

Russians always believe in robust engineering. What matters they fix it. In Su-35, they treated inlets with RAM plus compressor faces. They know that is not optimal from maintenance point of view.

Even with s duct, you need to do careful calibration each time around before the flight.

Another picture of F/A-18 Blocker:

http://img199.imageshack.us/img199/134/radarblocker.jpg

More about radar blockers:

"Aviation Week & Space Technology 03/19/2001

Stealth Engine Advances
Revealed in JSF Designs
DAVID A. FULGHUM/ORLANDO, FLA. and WASHINGTON

When Boeing revealed its full-scale JSF mockup at England's Farnborough air show last summer, most observers were shocked to see what appeared to be the engine face placed a few feet behind the opening of the air intake. One of the basic rules of stealth design is that you find a way to keep radar beams from striking the rotating parts of an engine. Engine faces traditionally produce large, sometimes amplified, and distinct radar reflections that can be analyzed to identify the engine and aircraft.

In a clever use of technology (a technique considered a proprietary secret by the two companies), Boeing and Pratt & Whitney worked together to add stealth to the inlet guide vanes to mask the fan blades behind them. The inlet vanes are variable and open to provide maximum air to the engine in vertical flight, but close to minimize radar reflections during flight at operational altitudes.

Compare with:

About PAK-FA, AIR INTERNATIONAL ARTICLE posted on BRF:
"-AMNTK Soyuz in Moscow will look after inlet guide vanes as well as rcs reduction for injun"

Company in question:

http://www.amntksoyuz.ru/en/

This is a radar blocker.