Sukhoi PAK FA

[ersakthivel]

look at similar profile pictures of lca and jf 17.
How is jf 17, gripen or any single engine fighter is different..all has the same advantage that engine on single engine fighter comes on center and the intakes naturally comes on sides..I am pretty sure all of them including tejas has either fully covers the blades or all of them partially covers the blades..I don't see tejas is any different from any of those.And remember pak fa could have used S DUCT but they didn't want to compromise speed and super cruise for stealth..similarly tejas would have been mach 2+ if the Intels were direct instead of y duct.

AFAIK Jf-17 was not designed with the same design low frontal RCS philosophy from the start of design phase,if you have any source to the contrary please give that.

The makers of tejas claimed it will have one of the lowest frontal clean config RCS in the world with close to 100 percent composite skin,

specially designed shaping techniques derived from computer simulation to reduce RCS in all directions,

high upper fuselage wing blending and no boxy rectangular edged air intakes ,

along with the help of Y duct intake,So RCS reduction measures on Tejas don't rely solely on Y duct intake alone.

If you have any source for such designing process used on JF-17 you can give me the source.

just count the number of sharp edged planes on the front of the fuselage and the umber of bumpy folds on the top surface of Jf-17.compare that with the smooth blended upper fuselage wing section of tejas along with no sharp edge and bumby folds air frame.

The reason JF-17 has all that is it is not a new design. It is a reworked Mig-21 with DSI, LREX added .

compare that to the smooth upper body fuselage blended wings of tejas which covers most of the weapons under it's huge wings,

So when tejas goes for a low level intrusion flight in the nap of the earth flying mode , it presents very few sharp edges to the AWACS or enemy fighter flying above,

Even its wings have a gently curved shape scattering radar ways all around, all the while covering air intake edges and sharp edges of air to air missiles and huge radar reflecting ground bombs.



compromising speed and super cruise has speed of PAKFA has nothing to do with serpentine air intakes,

F-22 uses serpentine intake does it compromises stealth?

PAKFA is no new stealth design. That is the root cause of the problem,

It was a Su-30 design optimized for stealth like SU-30 MKi- mk-2 type with a new engine and some shaping changes with intention of churning out a quick export product.

Whatever russians say about serpentine intakes compromising speed and super cruise as usual their own marketing effort to dodge the question why they did n't use better stealth complaint techniques in PAKFA.

Not all single engined fighters have the intake arrangement to hide engine blades, if you have any doubt you can look at the F-16 pic above,

 

[ersakthivel]

You can see the curved wing and smooth upper wing fuselage blending in tejas.

Most of its external weapons will be hidden below the huge wings as well not visible to AWACS flying above.

It it adopts a low level intrusion flight, ground radars too will have difficulty picking up the RCS emission from external weapons due to the curvature of the earth.

 

[Austin]

Boeing JSF never used serpentine intake and stealth was not the reason they were rejected ...YF-23 was considered as more stealthy than F-22 but that was not the reason why F-22 got selected .

Aviation Week & Space Technology Exclusive Report Unveils Stealth Engine On Joint Strike Fighter. - Free Online Library

"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," reports AW&ST.

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 U.S. has developed infrared and radar suppression devices for jet exhausts that have been flying on U.S. 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.

Knowledge of the emerging JSF technology also provides insight into the broader evolution of cheaper, reliable, low-maintenance stealth and critical low-observability improvements in other programs such as the Air Force's F-22 Raptor and Navy's F/A-18E/F Super Hornet.

The Joint Strike Fighter competition has yielded secrets about the stark differences in the methods contractors have used to manipulate stealth technologies - in particular to eliminate radar reflections from air inlets and engines.

According to the article, "The JSF competition is a good primer for how technology and tactics can be employed to keep radar from reflecting out of engine, exhaust and weapons bay cavities. The front of Boeing's JSF engine, for example, is only a few feet inside the air intake. To avoid radar reflections, the engine face has been hidden by special inlet guide vanes that have been treated with radar-absorbing materials (RAM) and shaped to cause radar beams to make multiple bounces, including onto the air-duct walls. There, radio-frequency energy is trapped by RAM or bounced from interior surfaces, each time being greatly attenuated. One way or another, the radar energy becomes too weak to constitute a dangerous reflection.

"By contrast, Lockheed Martin and McDonnell Douglas had both developed serpentine air ducts leading to the engine to avoid such reflections. The ducts coil horizontally and vertically on the way to the engine to avoid a line-of-sight path for radar. Once into the ducts, most radar beams are directed onto surfaces made of, or coated with, RAM. Radar specialists say that after a couple of bounces, there's virtually no radar energy left for a dangerous reflection."

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."

"Boeing's JSF demonstrator is designed for direct thrust from the engine to provide its STOVL capability," the article says. 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 ahead of the engine's face, similar to that developed for the company's F/A-18E/F. The Super Hornet design differs in that it combines slightly curved inlets with a blocking device on the engine face.

 

[ersakthivel]

Boeing JSF never used serpentine intake and stealth was not the reason they were rejected ...YF-23 was considered as more stealthy than F-22 but that was not the reason why F-22 got selected .

Aviation Week & Space Technology Exclusive Report Unveils Stealth Engine On Joint Strike Fighter. - Free Online Library

The front of Boeing's JSF engine, for example, is only a few feet inside the air intake. . Thats why radar blocker solution would have been adopted, if not they would have gone for fully hidden engine blade Y duct or serpentine intake version

JSF was mostly a compromise design to cater to the needs of marine corps lift fan version along with other versions.

If not they could have easily put a Y duct intake in this single engined plane to hide engine blades!!!!

So no point in taking the JSF version as the last word in stealth, SO it was a mistake on my part to add JSF to the list.

 

[Austin]

They went for the Blocker solution because a breakthrough in Materials and RAM ( proprietary of boeing ) The blocker is a more elegant solution without compromising on aerodynamics and achieving LO.

Even the modern JSF are made by materials that are more resilient to LO loss incase of partial structural cracks or damage something LM disclosed some time back ,and something not available earlier even to F-22.

LO for an aircraft is not an after thought but taken during design phase , so if Boeing knew they have something that negated the use of serpentine intake they went for it,

Even Sukhoi knew about serpentine intake via the S-37 Berkut program but having Blocker solution it went for PAK-FA.

 

[ersakthivel]

They went for the Blocker solution because a breakthrough in Materials and RAM ( proprietary of boeing ) The blocker is a more elegant solution without compromising on aerodynamics and achieving LO.

Even the modern JSF are made by materials that are more resilient to LO loss incase of partial structural cracks or damage something LM disclosed some time back ,and something not available earlier even to F-22.

LO for an aircraft is not an after thought but taken during design phase , so if Boeing knew they have something that negated the use of serpentine intake they went for it,

Even Sukhoi knew about serpentine intake via the S-37 Berkut program but having Blocker solution it went for PAK-FA.

F35 is like a jack of all trades compromise to have a common version produced in thousands to have a low cost stealth 5th gen plane,it was never about rivaling the stealth and air to air performance of F-22.

That is why it is way inferior to f-22 in every dept.



If the stealth solutions on FGFA or PAKFA are so elegant , truth will be known once the plane flies in many air forces and comparisons are made between it and F-22 stealth level.

But the RCS fig now being quoted as an average of 0.1 sq meter to 1 sq meter tells that PAKFA has much inferior stealth design compared to F-22(0.0001 sq meter in frontal RCS) at least in the all too important frontal RCS measurement.

If radar blocker solution was so effective then why is this difference in frontal RCS ?

IMHO this is due to radr blocker plus exposed engine blades solution adopted for PAKFA.

 

[Agnostic_Indian]

AFAIK Jf-17 was not designed with the same design low frontal RCS philosophy from the start of design phase,if you have any source to the contrary please give that.

I am not making a case for other aspects of -jf 17, I brought in jf17 only to show you that dsi in jf 17 is as effective or non effective as y duct of lca as far as hiding the fan blades is -concerned.so far what I read is jf17 dsi doesn't cover the fan blades entirely that means you can't be sure about tejas also unless ADA Specifically -claims so.

The makers of tejas claimed it will have one of the lowest frontal clean config RCS in the world with close to 100 percent composite skin, - -specially designed shaping techniques derived from computer simulation to reduce RCS in all directions, - high upper fuselage wing blending and no boxy rectangular edged air intakes , - -along with the help of Y duct intake,So RCS reduction measures on Tejas don't rely solely on Y duct intake alone. - If you have any source for such designing process used on JF-17 you can give me the source.

Tejas was never meant or designed to be a stealth fighter..it will have one of the low RCS figures among the 4.5 gen fighters..the" specially designed "etc like descriptions are very subjective..every one uses such terms.

- just count the number of sharp edged planes on the front of the fuselage and the umber of bumpy folds on the top surface of -Jf-17.compare that with the smooth blended upper fuselage wing section of tejas along with no sharp edge and bumby folds air frame. - The reason JF-17 has all that is it is not a new design. It is a reworked Mig-21 with DSI, LREX added .

As I said I am not arguing for jf17 on other aspects.

compare that to the smooth upper body fuselage blended wings of tejas which covers most of the weapons under it's huge wings, - So when tejas goes for a low level intrusion flight in the nap of the earth flying mode , it presents very few sharp edges to the AWACS or enemy fighter flying above, - Even its wings have a gently curved shape -scattering radar ways all around, all the while covering air intake edges and sharp edges of -air to air missiles and huge radar reflecting -ground bombs.

What about other fighter lets who can fly on same level ? Wouldn't they detect LCA ? What about ground radars ? when tejas goes low level attack(it doesn't have the kind of range to fly low level for long) you says it's weapons will be hidden under wings..but stations on the both outer edges of LCA will be projected out side..on other stations it depends on what type of weapon you carry..if it's small bombs them it could be ok..drope tanks on two side stations will project up to the same level of wing leading edges(if not further) now even if we assume AWAC is at 10 km hight and 100 km away then also the angle created will show the front portions of two drope tanks because it's hanging lower than the wing.if AWAC was rather close say 20-30 km at same hight(10 km above tejas) then the weapons would be hidden..

compromising speed and super cruise has speed of PAKFA -has nothing to do with serpentine air intakes,

Russians says otherwise and I have no reasons to not believe them since they already used s ducts on previous gen fighters.I have tried to Google that news in my memory but couldn't find it..but even then think about this. Tejas goes low flying and it's weapons are all hidden as you claim. Pakfa goes low flying and it's intakes also are hidden..so pak fa will be more stealthy than tejas on such mission. - Now if tejas is on medium or high altitude then it's drope tanks, weapon pods(as per your wish list), less stealthy shaping will compensate for the lack of S duct in pakfa. -

F-22 uses serpentine intake does it compromises stealth?

F22 can super cruise despite s duct thanks to better engine, small size etc..hopefully with new powerful engine pakfa would also be able to incorporate s duct if nothing else comes up as a better substitute.

PAKFA is no new stealth design. That is the root cause of the problem, - It was a Su-30 design optimized for stealth like SU-30 MKi- mk-2 type with a new engine and some shaping changes with intention of churning out a quick export product. - Whatever russians say about serpentine intakes compromising speed and super cruise as usual their own marketing effort to dodge the question why they did n't use better stealth complaint techniques in PAKFA.

That is a over simplified assessment.Pakfa -might have incorporated basic design philosophies of sukhoi but it's not mearly a stealth optimized su series..

- Not all single engined fighters have the intake arrangement to hide engine blades, if you have any doubt you can look at the F-16 pic above,

-

I know that's why I didn't mention f 16.I was only saying single engine fighter can naturally exploit the opportunity to incorporate intakes on sides..the opportunity is natural.

 

[Austin]

F35 is like a jack of all trades compromise to have a common version produced in thousands to have a low cost stealth 5th gen plane,it was never about rivaling the stealth and air to air performance of F-22.

That is why it is way inferior to f-22 in every dept.

F-35 still has better materials i.e more resilient to LO structural damage and has better avionics suite , kinetically it is inferior to F-22 and perhaps even in range.

But the RCS fig now being quoted as an average of 0.1 sq meter to 1 sq meter tells that PAKFA has much inferior stealth design compared to F-22(0.0001 sq meter in frontal RCS) at least in the all too important frontal RCS measurement.

Thats because the Russian calculate the average RCS of aircraft and according to them the RCS of F-22/F-35 is in 0.3 - 0.4 m2

BTW if you are interested in RCS discussion there is one going at Keypubs in PAK-FA thread.

 

[gadeshi]

RF patent on PAK FA RCS reducement methods:
Ïàòåíò íà èçîáðåòåíèå ¹2502643

 

[gadeshi]

 

[Agnostic_Indian]

what is it ?

 

[gadeshi]

Fuselage forward section with IRST and EOIS/MAWS fairings places.

 

[SajeevJino]

The T-50 Fighter Will Feature Even Greater Stealth Capabilities​

Thanks to a new design solution the PAK FA fighter has moved ahead of the American F-22 in its stealth capabilities.

The aircraft company Sukhoi managed to greatly reduce the effective surface scattering of the PAK FA, which is the basic element for visibility on aircraft radars. The average value of this indicator for the T-50 fighter is between 0.1 and 1 square meter.

In order to achieve this level of stealth, designers moved all weapons to the inside of the plane and also changed the shape of the air intake channel, also lining its walls with a material that absorbs radio waves.

Thanks to these new design solutions, the T-50 is now ahead of not only all other fighters of the Russian Army, but also foreign models. For example, the visibility of the American fifth-generation F-22 fighter is 0.3-0.4 square meters, according to PAK FA chief designer Alexander Davidenko.

Rostec enterprises produced the main parts of the T-50. The company Radioelectronic Technologies created the avionics and other radio-electronic needs for the fifth-generation aircraft. RT-Khimkompozit made the canopy and paneling. The T-50 is the first Russian combat aircraft made from a high proportion of composite materials, making up 25% of the mass of the aircraft and covering 70% of its surface.

The United Engine Corporation is designing the propulsion system for the fighter jet. The work for the fifth-generation engine is taking place at the company "Engines for Combat Aircraft." The T-50 prototype is already testing the first-phase AL-41F1 engines, a turbofan engine with afterburner and thrust vector control. With this engine the aircraft is capable of supersonic speeds without afterburner effects.

Aviation Equipment, another Rostec holding, developed a unique aviation system for the T-50, including a new power supply system that is two times more powerful than any of its Russian peers.


The T-50 Fighter Will Feature Even Greater Stealth Capabilities

 

[SajeevJino]

Thanks to these new design solutions, the T-50 is now ahead of not only all other fighters of the Russian Army, but also foreign models. For example, the visibility of the American fifth-generation F-22 fighter is 0.3-0.4 square meters, according to PAK FA chief designer Alexander Davidenko.

How He Know the Exact RCS value of F 22 ...I think the RCS value of F22 A Remains Secret

The average value of this indicator for the T-50 fighter is between 0.1 and 1 square meter.

How can he Clearly Measure say that Value can beat the F 22 ..since several kind of RCS methods of Available such as front looking side looking etc and Overall

 

[gadeshi]

01-5 on Kansk-Dalniy AB:

 

[Austin]

for any one interested in stealth , author is then Sukhoi Bureau Chief and director of the Institute of Theoretical and Applied Electrodynamics

Fundamental and Applied Problems STEALTH TECHNOLOGY

 

[cobra commando]

Patent analysis shows how PAK- FA differs from F-22 in air combat philosophy


Patent analysis shows how PAK-FA differs from F-22 in air combat philosophy | Russia & India Report

 

[p2prada]

How He Know the Exact RCS value of F 22 ...I think the RCS value of F22 A Remains Secret

How can he Clearly Measure say that Value can beat the F 22 ..since several kind of RCS methods of Available such as front looking side looking etc and Overall

You can put up scale models of the F-22 and then measure them. They obviously won't give accurate figures as a real F-22, but they provide the theoretical limits of the design itself. Build a similar model of PAKFA with the same materials and compare. Most of today's stealth comes from shaping.

Whether PAKFA moves one step ahead compared to the F-22 is yet to be seen.

For eg: Plasma cannot be retained at high speeds outside the aircraft. The aircraft can be built with radar transparent materials that allows the passage of radar waves through the skin. A plasma cloud inside the aircraft can be retained and used to absorb the radar waves, thereby employing the concept of destruction that RAM coatings do. The article that Austin just posted gives hints of plasma being used inside radar cone for the same application.

As of today, the real PAKFA is yet to undergo RCS tests, so they will know where PAKFA stands in terms of RCS at a later date.

 

[p2prada]

Patent analysis shows how PAK- FA differs from F-22 in air combat philosophy


Patent analysis shows how PAK-FA differs from F-22 in air combat philosophy | Russia & India Report

Silly assertions. The Russians claim they haven't compromised on aerodynamics for stealth, but that they have achieved near F-22 level stealth while doing it. This guy throws that assertion out the window.

 

[cobra commando]

Silly assertions. The Russians claim they haven't compromised on aerodynamics for stealth, but that they have achieved near F-22 level stealth while doing it. This guy throws that assertion out the window.

So simple case of d1ck measuring contest you're saying ?