PAK FA, T-50: News #1

Stealthflanker wrote:
Well we can have the "RAS" or RADAR Absorbing Structure to the sensitive part of the PAKFA.
And well with today's advanced computers.Stealth fighters may need lesser RAM materials than earlier gen.. the shape of the PAKFA can be optimized (and likely so) to counter those band (but well within possible size limit).

Stealthflanker wrote:
Well in 12.000 m however.. altitude where BVR may usually take place (lesser drag on missile and more efficient engine performance).. there's no cloud nor dust to hamper IRST from acquire its target from 80km++

The classic Western approach to stealth is 80 % design , 20 % composites. Since the PAK FA is designed to be super maneuverable therefore more emphasis has to be put on composites than design . Which means the entire aircraft has to be covered by the composites.

BVR is not altitude dependent . Long range missiles have their own set of problems. The problem with BVR missiles is that the distance the target can move after the missile leaves the aircraft and arrives to an interception area to scan for targets is quite long. In most cases the eventual fight will be WVR .

Sorry, what?

Stealth is either 100% design or it is nothing (ie low observable LO and not stealth).

If stealth was only 80% design then you would need to design stealth aircraft from scratch... you could modify the shape of an existing type... you can't if you want real stealth.

Real stealth is 100% design and RAM... composites have nothing to do with stealth and everything to do with reducing weight.

All composite gliders are not radar invisible stealth aircraft.

Don't confuse composites and stealthy addons like RAM they are NOT the same thing and are not even related.

Covering a conventional aircraft with a composite skin will not make it stealthy... in fact even if those composites were like the radar domes of fighter aircraft and were fully radar transparent making them the outside skin of an aircraft would mean the careful shaping design of the outer skin of the aircraft that is designed to refract the radar energy in all directions except the direction the original signal came from would not work. If the outer skin of the aircraft that was carefully shaped and carefully made to extreme tolerances was radar transparent how could its shape effect the beam of incoming radar energy and redirect it so it does not return to the radar that emitted it?

Also IRSTs are not Thermal Imagers and can easily detect targets through clouds... clouds reflect all visible wavelengths of light... which is why they look white, that doesn't mean they block all IR light too.

Stealth is Low Observable . True, some aircrafts like the Typhoon and Super Hornet are marketed by their producers as LO. So the buyer gets the impression that they are purchasing a "Stealth Aircraft" at the cost of a legacy ( 4th gen) aircraft .

Low observable properties are obtained by incorporating the radar absorbing material into the louver structure rather than the use of more traditional and higher maintenance surface coatings.

Radar absorbing intake structures can be designed to absorb electromagnetic energy over multiple bandwidths.

Stealth technology had begun with coatings that reflect less radar than the aluminum commonly used on airplanes.

In fact, the now thirty-year-old SR-71 reconnaissance aircraft made use of radar-absorbent coatings to help lower the risk of detection.

The airframe stealth geometry is only a partial answer for the contemporary radar development. Only the centimeter and millimeter long radar waves are effectively deflected by such method while the L-band radars remains a treat.

The word "STEALTH" has been sold to such an extent by US defense contractors that even till this date many countries believe that the F 22 & F 35 are indeed INVISIBLE to radar.

An object that is the size of a marble in S Band radar will be the size of a tennis ball in VHF band radar .

While it's true that a composite skin will not make an aircraft stealthy , neither will shaping .

However, composites especially those that Irkut is using for the Super Sukhoi program are nano-metric anti-radar covering that are much more light and stable.

Thick clouds act like a wall to the infrared energy.

Even wavelenghts beyond IR like Micro wave can see through clouds with limited accuracy.

IR and Visible Light are next to each other in the Electromagnetic Spectrum (IR is close to the Red of Visible light).

Seven years before its scheduled completion, the Ministry of Defence (MoD) has already announced a two-year delay in the Fifth Generation Fighter Aircraft (FGFA) India and Russia are to jointly develop.

Defence Minister A K Antony has been saying the FGFA would join the Indian Air Force by 2017. On Monday, his deputy, M M Pallam Raju, told Parliament, “The fifth generation aircraft is scheduled to be certified by 2019, following which the series production will start.”

The FGFA is the flagship of the Indo-Russian partnership. Both countries say it would be the world’s most advanced fighter. But interviews with Indian designers who have overseen the project suggest significant disquiet. There is apprehension the FGFA would significantly exceed its current $6 million budget, because this figure reflects the expenditure on just the basic aircraft. Crucial avionics systems would cost extra.

On the positive side, Indian designers say the FGFA project would provide invaluable experience in testing and certifying a heavy fighter aircraft that is bigger and more complex than the Tejas light combat aircraft (LCA), India’s foundational aerospace achievement.

The Russian and Indian air forces each plan to build about 250 FGFAs, at an estimated cost of $100 million per fighter. That adds up to $25 billion each, in addition to the development cost.

The FGFA’s precursor has already flown. In January 2010, Russian company Sukhoi test-flew a prototype called the PAK-FA, the acronym for Perspektivnyi Aviatsionnyi Kompleks Frontovoi Aviatsy (literally prospective aircraft complex of frontline aviation). Now, Hindustan Aeronautics Limited (HAL) will partner Sukhoi to transform the bare-bones PAK-FA into an FGFA that meets the Indian Air Force (IAF)’s requirements of stealth (near-invisibility to radar), super-cruise (supersonic cruising speed), networking (real-time digital links with other battlefield systems) and world-beating airborne radar that outranges enemy fighters.

But Sukhoi insists the PAK-FA already meets Russia’s requirements, says N C Agarwal, HAL’s design chief, who spearheaded the FGFA negotiations until his recent retirement. HAL worries Russia might ask India to pay extra for further development, particularly the avionics that transform a mere flying machine into a lethal weapons platform. That would leave the $6-billion budget in tatters.

The IAF clearly wants a top-of-the-line FGFA. According to Ashok Nayak, who spoke to Business Standard as HAL’s chairman before retiring last October, the IAF has specified 40-45 improvements that must be made to the PAK-FA. These have been formalised into an agreed list between Russia and India, the Tactical Technical Assignment.

A key IAF requirement is a ‘360-degree’ AESA (airborne electronically scanned active) radar, rather than the AESA radar that Russia developed. Either way, India would pay Russia extra: either in licence fee for the Russian radar; or hundreds of millions, perhaps billions, for developing a world-beating, 360-degree AESA radar.

Nor is the IAF clear on whether the FGFA should be a single-seat fighter like the PAK-FA, or a twin-seat aircraft like the Sukhoi-30MKI. A section of the IAF backs a single-seat fighter, while another prefers two pilots for flying and fighting a complex, networked fighter. During the ongoing preliminary design phase (PDP), for which India paid $295 million, the two sides would determine whether developing the PAK-FA into a twin-seat aircraft (inevitably more bulky) would reduce the FGFA’s stealth and performance unacceptably.

“The single-seat FGFA is essential for the IAF, and we will transform the Russian single-seat fighter into our single-seat version with a large component of Indian avionics. The twin-seat version will depend on the PDP conclusions,” says Nayak.

The PDP also requires Sukhoi to hand over design documentation to HAL, providing it a detailed insight into the design processes of the PAK-FA. Since India took years to decide to join the FGFA project, HAL missed out the design phase entirely.

The 18-month PDP, which terminates this year, will be followed by the ‘R&D phase’, which could take another seven years, says the HAL chairman. The FGFA would be designed in both countries. About 100 HAL engineers already operate from a facility in Bangalore. Another contingent would move to Russia to work in the Sukhoi design bureau.

“Our boys will learn the Russian language, their way of working, their design rules and their design norms. We are left-hand drive, while they are right-hand drive. The Russians say they would part with all these things,” says Nayak.

But the most valuable learning, say HAL executives, would take place during the FGFA’s flight-testing. “Unlike the basic design phase which we missed out on, we will actually gain experience during flight testing. This phase throws up dozens of problems, and we will participate in resolving these, including through design changes,” says Agarwal.

HAL designers also relish the FGFA’s specific challenges. For achieving stealth, its missiles, rockets and reconnaissance payloads are concealed in an internal bay under the wings. Before using these, a door slides open, exposing the weapon for use.

The Russians clearly believe HAL possesses useful capabilities, including the ability to design the AESA radar. Also attractive is India’s experience in composites.

“The LCA programme has generated a high level of expertise in composite materials within the National Aerospace Laboratory and some joint teams. The FGFA requires ‘higher modulus’ composites, which can withstand the 120-130 degree Centigrade temperatures that arise whilst flying at Mach 1.7 speeds,” says Agarwal.

Despite the continuing imponderables, HAL believes the FGFA project provides genuine technological skills, far more useful than licensed manufacture. Agarwal says, “We will pay some $6-7 billion to France for the licence to build the Rafale in HAL. In the FGFA project, a similar sum would bring in genuine design knowledge that will help us in the future.”

The joint Indo-Russian project to produce a fifth-generation fighter aircraft (FGFA) for the Indian Air Force is facing a two-year delay. It will now take nine years instead of the stipulated seven to develop. The Indian Air Force attributes the delay to Hindustan Aeronautics (HAL), which has a workshare of 25 percent in the program.

The two-seat FGFA is based on the single-seat Sukhoi T-50 PAKFA. HAL is tasked with supplying designs for the tandem seating and cockpit displays, none of which have been provided on time, a senior air force official told AIN. HAL is also responsible for navigation and countermeasure dispensing. Indian junior defense minister MM Pallam Raju recently confirmed the delay to Parliament, commenting, “The fifth-generation aircraft is scheduled to be certified by 2019 [instead of 2017], following which series production will start.” India and Russia concluded the $295 million preliminary design contract for the FGFA project in December 2010, during Russian President Dmitry Medvedev’s visit to India.

There are also concerns the FGFA will exceed its current estimated $6 billion development budget. The unit production price is predicted to be between $93- and $97 million. India will acquire 214 aircraft, making the total cost of the FGFA project at least $26 billion.

The 30-ton FGFA will be “a swing-role fighter with highly advanced avionics, giving 360-degree situational awareness, stealth to increase survivability and smart weapons,” said now-retired Indian Air Force Chief P.K. Naik. Capable of covering long ranges without refueling, it will feature supercruise along with advanced mission computers. The Indian Air Force has specified 43 improvements to the design following its observation of flying trials at the Zhukovsky airbase.