Sukhoi Su-57 / T-50 / PAK FA - flight testing and development Part II [2012-current]

[saintkatanalegacy]

Maneuverable aircraft: http://www.findpatent.ru/patent/250/2503584.html

The invention relates to aviation and the concerns maneuverable aircraft systems and their management. Maneuverable aircraft comprises a fuselage, swept wing, front swept nodules, controls, chassis. Front nodules located at the junction of the head and middle portions of the fuselage and equipped with controlled rotary surfaces. The axes of the steering surfaces arranged perpendicularly or sagging under an angle to the longitudinal plane of the aircraft. Achieved by enhancing the safety and combat effectiveness of the aircraft by increasing stocks diving moment and thus extend the range of allowable center of gravity and increase the resources of the combat equipment of the aircraft, the implementation of the best combination of lift and drag. 3 ill.
The invention relates to aviation, namely maneuverable aircraft systems and their control of the aircraft. Known maneuverable plane containing the fuselage, swept wing of moderate sweep, sweep large influxes front, controls, chassis (RU, 2302975 C2). Known aircraft has high lifting properties at subsonic and supersonic regimes. At supersonic speeds front sags significantly shift the focus of the aircraft forward, thereby providing a reduction in the stock of the static stability of the aircraft, which in turn, reduces the loss of aerodynamic performance for balancing increases the maneuverability of the aircraft. As disadvantages of the aircraft should indicate the following. At supercritical angles of attack, when to end the wing stall occurs, the front nodules continue to create the lift force, creating time to pitch, resulting in a decrease in disposable moment to dive, and for aircraft with a full set of external load, even to his absence (for maximum rearward center of gravity).
Technical result, The aim of the invention is to improve safety and combat effectiveness of the aircraft by increasing stocks diving moment and thus extend the range of allowable center of gravity and increase the resources of the combat equipment of the aircraft, as well as implement the best combination of lift and drag.
The inventive that in maneuver plane containing the fuselage, swept wing, front swept nodules, controls, chassis, front nodules located at the junction of the head and middle portions of the fuselage and equipped with controlled rotary surfaces, the axes of rotation of the control surface sag arranged perpendicularly or obliquely to the longitudinal plane of the aircraft.
The invention is illustrated by drawings, where Fig. 1 shows a maneuver plane when viewed from above, Fig. 2 - maneuverable aircraft in side view, Fig. 3 - maneuverable aircraft from the front.
Maneuverable aircraft comprises a fuselage 1, 2 swept wing, front swept nodules 3, controls, including vertical and horizontal 4 5 plumage chassis.
Front swept three nodules located in the zone of articulation head and middle portions of the fuselage 1 and provided with controllable swivel surfaces 6, wherein the pivot axis of the front control surfaces 3 6 burls are arranged perpendicular or at an angle to the longitudinal plane of the aircraft.
Maneuverable aircraft, comprising articulated fuselage, wing and front-swept swept nodules has high lifting properties at angles of attack is more critical (about 26), the flow separation from the wing in such a plane substantially postponed to large angles of attack (α = 35 to °).
The combination of longitudinal static instability at subsonic and reduced static stability at supersonic flight speeds significantly expands its maneuvering capabilities.
However, statically unstable aircraft in the longitudinal channel burly front of the wing, there is the problem of providing stock diving moment at angles of attack is more critical. At angles of attack - α, close to critical (α = 26 °), there are failures on the end portions of the flow wing stall as part turbulent flow occurs at much higher angles of attack. Which leads to an increase in pitching moment, which, combined with a sharp drop in the efficiency of the longitudinal control leads to a decrease (or even failure) disposable moment on dive. In case of accidental contact with the aircraft at high angles of attack supercritical (eg modes corkscrew or hovering at high angles of attack) dive after pitching moment of the longitudinal control setting for the gathering with high angles of attack is enough to put the aircraft at small angles of attack. Therefore, to meet the needs of disposable torque limiting maximum allowable rear alignment of the aircraft. Because of modern combat aircraft Suspended loads on the fuselage and wing mostly shift the center of mass of the aircraft back, we have to reduce the amount of suspended loads, and consequently degrade the combat potential of the aircraft.
In addition, a fixed influx, increasing lift of the wing does not provide for small and medium angles of attack implementation best balance lift and drag (polars) aircraft.
To improve safety and combat effectiveness by increasing stocks diving moment and a corresponding expansion of the range of allowable center of gravity and increase the resources of the combat equipment of the aircraft, as well as implement the best combination of lift and drag front sags 3 stocked controlled rotary surfaces 6 and trailing edge in undeflected position tight to the front of the stationary part of the influx of 3, located in the following (downstream).
In the event-driven rotary surfaces 6 at supercritical angles of attack reduced load carrying properties and increased disposable aircraft nose down moment. In the event-driven rotary surfaces 6 at small and medium angles of attack provides the best value for the lift and drag of the aircraft.
Deflection controlled rotary surfaces 6 automatically. Deviation algorithm is formed based on the current angle of attack (by a certain law) and longitudinal control body position - horizontal tail and 5 simultaneously optimally maintains high load-bearing properties of the wing 2, provides the necessary supply of diving moment at supercritical angles of attack and enables a rear alignment.
Maximum deflection angle controlled rotary surfaces 6 on the dive is about 60 °.
Managed rotary surfaces 6 significantly improves the maneuverability of the aircraft, improve its combat capabilities and increases the safety of its operation.
Additionally driven rotary surface 6 are used for braking the aircraft after landing on the run after a touchdown by the front desk completely on their deviations dive. Controlled rotary surface 6 may be made in the following embodiments:
- A pivot axis disposed at an angle to the longitudinal plane of the aircraft;
- A pivot axis perpendicular to the plane of symmetry of the aircraft. Supersonic modes driven rotary surface 6 are in a fixed position, ie do not deviate.
Agile aircraft comprising a fuselage, swept wings, front swept nodules, controls the chassis, characterized in that the front nodules located at the junction of the head and middle portions of the fuselage and are provided with controllable swivel surfaces, wherein the axis of the steering surfaces arranged perpendicularly or sagging under angle to the longitudinal plane of the aircraft.

 

[Triton]

http://youtu.be/4Srsp8OGW2Y

 

[Triton]

http://youtu.be/0TVkw0Iwxzw

 

[Triton]

http://youtu.be/pZQpEaB2tl0

 

[donnage99]

You have no evidence of kinematic advantage. Basic physics favor a centerline mass more agile than two boxy outboard weights that counteract each other. F-14 had similar centroplane, yet it was not used on any western 5th gen.

Well the only Western 5th generation fighters are f-22 and f-35, which are both designed by Lockheed, employing the same philosophy. However, if you look at the case of yf-23, Northrop did not employ the central mass philosophy as Lockheed. I would have a hard time swallowing the idea that Northrop chose the more conservative (older) yet inferior design during the ATF competition

 

[kcran567]

I agree Donnage. There were some trade-offs. I like all 3 aircraft though

 

[overscan (PaulMM)]

You have no evidence of kinematic advantage. Basic physics favor a centerline mass more agile than two boxy outboard weights that counteract each other. F-14 had similar centroplane, yet it was not used on any western 5th gen.

Well the only Western 5th generation fighters are f-22 and f-35, which are both designed by Lockheed, employing the same philosophy. However, if you look at the case of yf-23, Northrop did not employ the central mass philosophy as Lockheed. I would have a hard time swallowing the idea that Northrop chose the more conservative (older) yet inferior design during the ATF competition

All things being equal (which they rarely are) putting your engines outboard may affect roll speed. To compensate you might use larger control surfaces or more powerful actuators (with possible weight penalties) Or accept a slightly lower rate of roll if it doesn't stop you meeting requirements. If the outboard engine design has other advantages, you may consider this minor drawback a worthwhile tradeoff. That's how aircraft design works in the real world. Nothing is free. The MiG-29 / Su-27 design was optimised for transonic conditions and loses out majorly to Typhoon in supersonic speeds.


I note that F-16 pilots who've flown the Su-27 and MiG-29 note they are slower to ramp up to maximum roll rate, while F-16 is well known to have an excellent roll rate - partly due to its lower aspect ratio wings and central engine.

 

[saintkatanalegacy]

I'm surprised nobody's discussing the patents posted since they say a LOT about the plane in general

 

[Sundog]

India criticizes the T-50

Based on the three statements India made regarding the FGFA, my response is;

a) duh!
b) duh!
c) duh!

There must be something else going on, because none of those three statements are news. At least not to anyone on SP. Perhaps the IAF needs to read more SP?
There's been so much talk about the new engine designed for the T-50 that there must have been a news black out in India.

 

[Triton]

Looks like the Indian Air Force will just have to embrace the suck.


"Joint production to be norm in new Indo-Russian defence projects"
January 21, 2014 Rajeev Sharma, specially for RIR

Source:
http://indrus.in/economics/2014/01/21/joint_production_to_be_norm_in_new_indo-russian_defence_projects_32419.html

The current focus in Indo-Russian bilateral relations is on consolidation and sticking to conventional diplomacy. This unwritten, unsaid policy is in place in all fields of Indo-Russian ties, particularly in the defence arena. Movers and shakers of India’s Russia policy believe that Indo-Russian relationship is too crucial to be allowed to go adrift, but the need of the hour is to deliver on current projects rather than keep on signing new defence deals.

Moreover, the Indian political system has already hit the pause button with general elections scheduled to be completed before May this year. The new government would take at least four to six weeks to settle down, meaning that nothing spectacular should be expected in Indo-Russian ties in the first half of this year.

A key Indian official responsible for navigating Indo-Russian relations said things are panning out well. An example of this was the BrahMos supervisory council that met in Moscow last week.

The official did not divulge details of what transpired at the meeting and refused to say whether the issue of export of BrahMos missiles to third countries was taken up. The official, however, said that all major points of differences between the two sides on the project were removed at last week’s meeting.

The official disclosed that many new defence deals would come up between India and Russia later this year but declined to give specific details. It is understood that outright purchases by India from Russia would be few and far between. Instead, the flavor of the season is to go for joint production.

A major highlight of Indo-Russian relations in 2014 is expected to be the fifth generation fighter aircraft (FGFA), whose first prototype delivery has already been delayed by about two years and is now expected later this year.

FGFA to be a major test case

India is keeping a very close watch on the progress of the FGFA project which has a potential of becoming the biggest and most expensive Indo-Russian defence project costing India $30 billion. However, New Delhi will loosen its purse strings only if its concerns about value for money, cost-overruns, delays and 40 to 45 improvements in the fighter aircraft’s design demanded are met by the Russians.

The next big thing on the FGFA project is signing the R&D phase of the project which is likely to cost $11 billion.

Much depends on how soon the first prototype is delivered to India and how it performs during trials in the Indian skies. In August 2012 the then chief of Indian Air Force (IAF) Air Chief Marshal NAK Browne had gone on record as commenting thus: “The first prototype of the FGFA is scheduled to arrive in India by 2014 after which it will undergo extensive trials at the Ojhar air base (Maharashtra)...we are hopeful that the aircraft would be ready for induction by 2022.”

India has already conveyed its unease to the Russians over the fact that it is getting only 15 percent of the research and development work share despite paying half the development cost. The Russians have promised to do the needful.

The second and third prototypes are to arrive in India in 2017 and 2019 respectively and the IAF has planned to induct the fighter by 2022, if all goes well.

The Indians are increasingly laying focus on self-reliance and not taking recourse to outright purchase of defence equipment from foreign sources unless it is absolutely critical to national security and such technology is not available in India. This policy is unlikely to be changed by the new government whichever party comes to power.

 

[Avimimus]

FYI - there now appears to be footage showing the fifth prototype firing an RVV-MD from one of its central bays.

 

[Radical]

When was the external design of the PAK FA approved? I'm reading conflicting reports of 2009, 2007, and even as early as December 2004.

 

[flateric]

FYI - there now appears to be footage showing the fifth prototype firing an RVV-MD from one of its central bays.

that's VERY old fan's animation

 

[Reaper]

Note to the T-50 patent: Is it even possible to patent the whole aircraft? The LERX or single technologies ok, but the whole? That would also mean that a future Russian Light Combat Aircraft (MiG-29 successor) couldnt be build in the T-50 fashion since it would fall in this patent category.

 

[Avimimus]

FYI - there now appears to be footage showing the fifth prototype firing an RVV-MD from one of its central bays.

that's VERY old fan's animation

The footage in question can be found at 12 minutes 27 seconds:

http://youtu.be/8eWoYZi3jfY?t=12m27s


I'll take your word for it though. The particle effects do look a bit off.

 

[bobbymike]

https://medium.com/war-is-boring/d89b9ce721de

 

[flateric]

[quote author=Avimimus]I'll take your word for it though. The particle effects do look a bit off.
[/quote]
you could check for example Inlets lower lips angle for the beginning to understand that it's cgi at once...

 

[donnage99]

I don't know how to take the claims made by the Indians. It could bear some truth in it, but it also could have been a political move to pressure Russia in sharing more of the burden.

 

[kaiserbill]

I don't know how to take the claims made by the Indians. It could bear some truth in it, but it also could have been a political move to pressure Russia in sharing more of the burden.

The fact that they are highlighting the fact that it currently has engines derived from the Al-31, when everybody and his dog knows this, and that the new engine slated for production (batch 2?) T-50 PAK FA's is currently in testing, as it has been made clear for years, means that I would take what they've said with a pinch... nay, a sackfull of salt.

Indian weapons procurement processes are very strange...

 

[flanker]

When was the external design of the PAK FA approved? I'm reading conflicting reports of 2009, 2007, and even as early as December 2004.

Why would they approve the design *after* several prototypes were already being built? It was in 2004. More detailed engineering started after that.

 

[Rlewis]

I don't know how to take the claims made by the Indians. It could bear some truth in it, but it also could have been a political move to pressure Russia in sharing more of the burden.

The fact that they are highlighting the fact that it currently has engines derived from the Al-31, when everybody and his dog knows this, and that the new engine slated for production (batch 2?) T-50 PAK FA's is currently in testing, as it has been made clear for years, means that I would take what they've said with a pinch... nay, a sackfull of salt.

Indian weapons procurement processes are very strange...

unless they are concerned with the development of the future engines themselves or that those engines may be delayed or postponed ? :-\

 

[flanker]

The fact that they are highlighting the fact that it currently has engines derived from the Al-31, when everybody and his dog knows this, and that the new engine slated for production (batch 2?) T-50 PAK FA's is currently in testing, as it has been made clear for years, means that I would take what they've said with a pinch... nay, a sackfull of salt.

Indian weapons procurement processes are very strange...

A few things. First off, while 117 is derived from Al-31F to a certain degree, there is very little they share in common. I have heard 70-80% of the parts are different from Al-31F, but that was from Saturn and for state television. So some salt is needed.

And 117 will be serially produced for T-50, for the first 60 frames or so til the second stage engine is finished. *Elements* of it is being tested, not the whole engine.

 

[Triton]

"T-50 Fighter To Feature Higher Stealth Capabilities"
Wednesday, January 15, 2014

Source:
http://www.defenseworld.net/news/9835/T_50_Fighter_To_Feature_Higher_Stealth_Capabilities#.UuK8FbSIbDc

Sukhoi Aircraft has introduced the new design solutions to increase the stealth capabilities of T-50 by managing to greatly reduce the effective surface scattering of the fighter, which is the basic element for visibility on aircraft radars.

An 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.

The company claims that this new design has increased the capabilities of T-50, comparing the visibility of the American fifth-generation F-22 fighter which 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.

 

[Triton]

"PAK FA stealth features patent published"
Piotr Butowski, Poland - IHS Jane's International Defence Review
09 January 2014

Source:
http://www.janes.com/article/32190/pak-fa-stealth-features-patent-published

Details of the Sukhoi Design Bureau's work on the stealthy aspects of the T-50 PAK FA fighter aircraft emerged in late December 2013, when the company's patents were published.

According to the patent paperwork, taken together, all of the stealthy measures offer significant improvements over legacy fighter designs. The papers claim that the radar cross-section (RCS) of an Su-27 was in the order of 10-15 m 2 , with the intention being to reduce the size of the RCS in the T-50 to an "average figure of 0.1-1 m 2 ".

In common with other low observable aircraft designs, this reduction is achieved throught the use of radar-absorbing and radar-shielding materials and coatings, panel shaping (especially around the air intakes) and in the design of the junctions between moving elements, such as flaps and hatches.

In particular, the patent spells out the benefits of internal weapons carriage, s-shaped engine air ducts, (which were considered but are actually not implemented in the production PAK FA), and the use of radar blockers. It adds that the inlet guide vanes of the engines' compressors generate "a significant portion [up to 60%] of the radar cross-section of the airframe-powerplant system in the forward hemisphere" and that this is reduced by using radar-blocking devices and radar-absorbing coatings in the walls of the air ducts.

The shape of the airframe reduces the number of directions that radar signals are reflected in with the angles of sweep of the wings and the tail plane's leading and trailing edges, the edges of the air intakes and hatch covers being reduced and deflected from the aircraft's axis. Viewing the aircraft from the flank, the fuselage sides, lateral edges of the air intakes and vertical empennage are all deflected at the same angle.

Some openings and slots on the airframe's surface - such as the boundary-layer bleeds on the sides of the air intakes and the openings on the upper fuselage immediately aft of the cockpit - are covered with a thick grid, featuring a mesh of less than one quarter of the wavelength of a search radar, which reduces the reflections from these uneven surfaces. Gaps between the airframe elements are filled with conducting sealants, while the glazing of the cockpit canopy is metallised.

The surfaces of the PAK FA's own five radar arrays are also angled off from the vertical plane, helping to 'deflect' enemy radar signals. The covers of the radar arrays are selective, letting through their own signals, but blocking other frequencies. Additionally, the array compartments are edged with radar-absorbing 'curtains' to reduce possible leaks of these amplified signals.

Antennas are recessed from the surface of the skin to reduce protuberances (the vertical empennage serves as a communications antenna), while the turret of the aircraft's nose-mounted infrared search-and-track (IRST) sight is rotated backwards into a cruise position, exposing its rear hemisphere, which is covered with a radar-absorbing coating.

The release of this list of patents follows the July 2013 release of documentation covering the configuration of the fighter's integrated avionics suite.

There are currently five T-50 prototypes - the latest, T-50-5, first flew on 27 October 2013 - supporting the development programme and they are believed to have undertaken over 300 sorties to date.

In the 'Schedule of Activity for the Russian Ministry of Defence for 2013 to 2020' published in mid-2013, the PAK FA's Initial Operational Capability and the launch of full-scale series production is scheduled for 31 December 2016. The Russian National Armament Programme stipulates that 60 production PAK FA fighters will be delivered between 2016 and 2020.

The assembly of aircraft T-50-6-1 is nearing completion and three further aircraft (T-50-6-2, T-50-7 and T-50-8) are in build. One of the T-50-6 aircraft is intended for static trials and the other one is intended for flight testing.

 

[sferrin]

0.1 - 1 m^2 seems significantly worse than either the F-22 or F-35. What's a Super Hornet's?

 

[Triton]

"Russia Offers Joint Productions On All Future Defense Deals With India, As IAF Reportedly Criticizes FGFA Deal"
Source : Our Bureau ~ Dated : Wednesday, January 22, 2014 @ 11:24 AM

Source:
http://www.defenseworld.net/news/9876/Russia_Offers_Joint_Productions_On_All_Future_Defense_Deals_With_India__As_IAF_Reportedly_Criticizes_FGFA_Deal#.UuLB5bSIbDc

Joint productions of all future projects is expected to be the new norm in Indo-Russian relations after Moscow last year offered to set up manufacturing facilities in the country for joint production of defence hardware.

India and Russia agreed to set up manufacturing facilities in India for joint production of defence hardware during Deputy Prime Minister of Russia Dmitry Rogozin’s state visit to New Delhi last year.

The two countries are reportedly on the brink of signing various new defence deals this year such as the contract to integrate the Brahmos cruise missile aboard the multifunctional fighter Su-30MKI, the joint development of the Multirole Transport Aircraft (MTA), a $471 million contract to supply Invar Anti Tank Guided Missiles to the Indian arm and a $ 3 billion deal to procure 42 new Su–30 MKI combat aircraft and 71 Mi–17V5 medium-lift helicopters.

However, the Indian Air Force is reported to have has criticized the $6 billion project (expected to be signed soon) and has alleged the Russians would be unable to meet their promises about its performance.

An Indian newspaper, Business Standard reported that the IAF's deputy chief of air staff (DCAS) said the FGFA's engine was unreliable, its radar inadequate, its stealth features badly engineered, India's work share too low, and that the fighter's price would be exorbitant by the time it enters service.

The Indian Ministry of Defense had earlier rejected the prospect of buying the American fifth generation F-35 Joint Strike Fighter, declaring the FGFA would suffice. According to Indian scientists, the knowledge gained from the FGFA will help India develop an indigenous fifth generation fighter called the Advanced Medium Combat Aircraft (AMCA).

The next step in the FGFA project is the signing the R&D phase of the project which is likely to cost $11 billion. India and Russia, in 2010, signed the preliminary design contract (PDC) worth $295 million under which Indian designers and scientists were even stationed in Russia to work out the blueprints and documentation for the fighter.

Last year, the project fell under a cloud after Russia hiked the cost of manufacturing the aircraft. The project could end up costing India over $35 billion over the next two decades from the original $30 billion for over 200 fighters.

However, HAL has reportedly proposed to surrender 30 percent of its 50 percent work share – a move that has allegedly left the Indian Air Force fuming. India has also reportedly expressed its unhappiness over the fact that it is getting only 15 percent of the research and development work share despite paying half the development cost.

The second and third prototypes are to arrive in India in 2017 and 2019 respectively and the IAF has planned to induct the fighter by 2022. In 2012, then Air Chief Marshal NAK Browne, announced the IAF would buy only 144 FGFAs instead of the 214 that were originally planned.

The FGFA will be based on the Sukhoi T-50 (which has four variants) and will be developed to suit the IAFs needs.

The IAF had initially pitched for 166 single-seat and 48 twin-seat fighters but will go for only single-cockpit jets now to reduce costs as well as protect stealth features

Currently, Russia is testing several prototypes of the T-50 aircraft, which is due to enter service with the Russian Air Force after 2017.

India has expressed interest in developing some of the aircraft's computers, software, guidance systems and other systems, as it did for a similar project with Russia producing a locally-made variant of the Sukhoi Su-30MKI strike aircraft.

 

[GTX]

I wonder…is Russia getting worried at India's increasing looking towards the west: Rafale (eventually…), C-17, P-8...

 

[Avimimus]

0.1 - 1 m^2 seems significantly worse than either the F-22 or F-35. What's a Super Hornet's?

It rather depends on how the calculations are done doesn't it?


Some of the solutions are interesting - isolating the radar antennas, having a reversible IR search system... it also sounds like there may be plasma shields on some of the antennas?

 

[Triton]

I wonder…is Russia getting worried at India's increasing looking towards the west: Rafale (eventually…), C-17, P-8...

I have been wondering about that as well. On December 27, the Indian MoD ordered six additional Lockheed Martin C-130J Hercules transport aircraft for $1 billion bringing the total inventory to 12. Will the Indian Air Force replace its aging fleet of Antonov An-32 transport aircraft with the C-130J rather than the UAC/HAL Il-214 Multirole Transport Aircraft (MTA)? Russia seems to be relying on assistance from India to fund new aircraft development.

 

[sferrin]

0.1 - 1 m^2 seems significantly worse than either the F-22 or F-35. What's a Super Hornet's?

It rather depends on how the calculations are done doesn't it?

What would be the point of them stating a number if they weren't comparing apples to apples?

 

[Triton]

"Gunning for the PAK-FA: What the IAF really wants"
January 24, 2014 Rakesh Krishnan Simha

Source:
http://indrus.in/blogs/2014/01/24/gunning_for_the_pak-fa_what_the_iaf_really_wants_32535.html

The Indian Air Force’s ack-ack salvo at the Russian-Indian PAK-FA stealth fighter programme has surprised defence industry watchers. But the spat is hardly unique and in fact mirrors the difficulties the United States and its close allies are experiencing over the troubled F-35 Joint Strike Fighter.

The IAF has five major complaints: the PAK-FA is too expensive, its engine unreliable, radar inadequate, stealth features badly engineered, and finally that India’s work share is too little. These complaints have an uncanny parallel to the issues dogging the American stealth programme, which has been blasted by the media, future customers and US lawmakers.

Technology: It’s a work in progress

Fifth generation fighter aircraft (FGFA) programmes everywhere are experiencing serious teeth problems. The F-35 might be a uniquely disastrous project but even its big brother, the F-22 Raptor, is not out of the turbulence zone entirely. While the Americans claim the stealth interceptor is the best fighter ever created, several pilots have been spooked by performance issues beyond the F-22’s potentially deadly oxygen problem.

Considering that the Russian aerospace industry is smaller and less experienced than the Americans in designing and manufacturing high performance stealth aircraft, it’s almost certain they’ll face all sorts of issues as work progresses. But what’s also certain is the Russians – and their Indian partners – will sort out these glitches at various prototype stages.

So what’s the IAF getting paranoid about?

In India, the military does not dictate defence procurement policy – the civilian bureaucracy at the Ministry of Defence (MoD) does. So when a highly disciplined organisation such as the IAF uncharacteristically slams its own future fighter, then you can be sure the IAF brass is trying to put pressure on the MoD.

Fighter envy

A professional fighting force such as the IAF is surely keeping a close watch on the Chinese J-20 and J-31 stealth aircraft programmes. The two Chinese aircraft have an uncanny resemblance to the American F-22 and F-35. This is because Chinese intelligence managed to steal the technology and blueprints relating to both aircraft.

The IAF’s worry is that the Chinese aircraft could end up being better than the PAK-FA. That would indeed be a disaster because the IAF will end up facing superior stealth aircraft on both the Western and Himalayan borders, assuming Beijing sells these fighters to Pakistan.

The IAF is hoping the MoD will send a clear message to the Russians: we don’t mind being second best to the United States, but we certainly don’t want to be second best to China or Pakistan.

The IAF’s fears are understandable. The arrival of the MiG-29 and the Sukhoi-30 MKI in the 1990s has given it a fearsome qualitative advantage over the Pakistan Air Force. For the first time since the 1960s – when the PAF acquired the F-104 Starfighters and F-86 Sabres from the United States – the IAF has aircraft that is a generation and a half ahead of the PAF. Ceding that advantage would be undoubtedly painful for the IAF.

Share of work: Too little or too much to handle?

India had earlier complained that Sukhoi is giving it only 15 percent of the R&D work share despite India paying half the development cost. It has expressed interest in developing some of the aircraft’s computers, software, guidance systems and other systems, as it did for a similar project with Russia producing a locally-made variant of the Sukhoi Su-30MKI strike aircraft.

The problem is Sukhoi may have its own legacy systems it wants to sell.

There is another parallel here – France’s Dassault, which had promised (or rather over-promised) it would offset 50 per cent of the Rafale fighter work to India, is now backtracking. Its argument is that Hindustan Aeronautics Ltd (HAL), which is India’s leading aircraft maker, is not capable of absorbing the technology.

While the French are known to be a crafty bunch, and clearly want to welch on their promise, what’s undeniable is HAL has its limitations. Last year the public sector company reportedly offered to surrender 35 percent of its 50 per cent work share in the PAK-FA project.

HAL’s copout had left the IAF fuming. Putting pressure on the MoD – which runs HAL – is perhaps the IAF’s insurance policy to ensure HAL does not spring such a nasty surprise again.

Costs: Expect prices to balloon

If the American stealth aircraft programme – or for that matter any weapons project – is an indicator, then the PAK-FA is likely to overshoot its budget. It’s almost a rule that big ticket weapons programmes come with cost overruns.

The project could end up costing India over $35 billion over the next two decades from the original $30 billion. With India paying $6 billion to co-develop the FGFA, a large percentage of the IAF’s capital budget will be locked up.

Perhaps the thinking at Air Headquarters is to fast forward the Rafale purchase by freeing up some cash earmarked for the PAK-FA. The stealth fighter being a project of strategic importance will get more cash anyway. Something along the lines of the Gorshkov aircraft carrier refurbishment, which India kept feeding until the costs ballooned from under a billion to more than $3 billion.

Synergies are the key

While the IAF’s urgency is justified, there’s no need to panic – as yet. The PAK-FA project may indeed be rocket science but both Russia and India have the means to see the project through. Russia has the technology and India has the cash. More importantly, both countries have a pressing need for a stealth fighter. If necessity is the mother of invention, then this is the time.

Defence Industry Daily has an excellent take on the Russian-Indian project. “Russia wants a 5th generation fighter that keeps it competitive with American offerings, and builds on previous aerial and industrial success. India wants to maintain technical superiority over its rivals, and grow its aerospace industry’s capabilities. They hope to work together, and succeed. Will they?”

 

[Triton]

"Patent analysis shows how PAK-FA differs from F-22 in air combat philosophy"
January 16, 2014 Rakesh Krishnan Simha

Source:
http://indrus.in/blogs/2014/01/16/patent_analysis_shows_how_pak-fa_differs_from_f-22_in_air_combat_philos_32309.html

The PAK-FA patent document published by Russia’s Federal Service for Intellectual Property shows the fifth generation stealth aircraft’s design is heavily influenced by low radar visibility requirements. At the same time, the Russians are prepared to sacrifice some stealth in their quest for super maneuverability and excellent flight characteristics.

The aim of the invention, say the patent papers, is to provide an aircraft having low radar visibility, super maneuverability at high angles of attack (close to an astounding 90 degrees), and simultaneously preserving high aerodynamic efficiency at subsonic speeds.

Creating an aircraft that is capable of performing tasks in a wide range of altitudes and flight speeds and also has a low radar signature is a technical challenge, the Russians admit. “All these requirements are contradictory, and the creation of an airplane that meets these requirements represents a compromise.”

On the radar screens

The papers claim that the intention of the designers is to reduce the radar cross-section (RCS) of the aircraft to an “average figure of 0.1-1 square metre”. At this range the aircraft appears like a bird on enemy radar and becomes difficult – though not impossible – to spot.

The Sukhoi compares well with the American F-22 stealth fighter which aviation experts believe has an RCS of 0.1 square metre. (The actual figure is classified) Fourth generation fighters such as the Sukhoi-27/30 and F-15E have an RCS in the range of 10-15 square metres.

Reducing the radar visibility of the aircraft is achieved through a combination of design and technology, in particular by shaping the contours of the airframe.

According to Piotr Butowski of Jane’s International Defence Review, “Some openings and slots on the airframe’s surface – such as the boundary-layer bleeds on the sides of the air intakes and the openings on the upper fuselage immediately aft of the cockpit – are covered with a thick grid, featuring a mesh of less than one quarter of the wavelength of a search radar, which reduces the reflections from these uneven surfaces. Gaps between the airframe elements are filled with conducting sealants, while the glazing of the cockpit canopy is metallised.

“The surfaces of the PAK-FA’s own five radar arrays are also angled off from the vertical plane, helping to ‘deflect’ enemy radar signals. The covers of the radar arrays are selective, letting through their own signals, but blocking other frequencies. Additionally, the array compartments are edged with radar-absorbing ‘curtains’ to reduce possible leaks of these amplified signals.”

Versatile aircraft

The PAK-FA’s two engines are placed apart in isolated pods, creating space for a large cargo compartment in between. The air intakes are located further apart in respect to the vertical and horizontal planes than the engines, creating a curvature that hides the compressor and reduces the radar signature of the aircraft from the front.

The engines are also placed at an acute angle relative to the vertical plane, allowing thrust vectoring – an area in which Sukhoi excels – in the longitudinal, transverse and travel channels. The engine nozzles point outwards, which transfers a significant portion of the control of the aircraft to them even at low altitudes. This considerably improves flight safety.

The movable airfoil above and in front of the engine air inlets is a unique feature of the PAK-FA, and is typical of Russian ingenuity in airframe design. The airfoils can rotate downwards around their rear edge. Similar to wing slats, they assist control when the aircraft is at high angles of attack. The air intakes are located on each side of the fuselage and they are bevelled in two planes in order to maintain flow even at high angles of attack.

PAK-FA weaknesses

The paper also lists some of the disadvantages of the aircraft:

The inability to control roll and yaw channels when flying at low speeds because the engines are located close to each other.

The curved shape of the air intake duct requires an increase in their length, and therefore, the mass of the airplane.

The inability to ensure the “vanishing” of the aircraft during supercritical angles of attack.

The use of fixed keels with rudders requires increasing the required area of the vertical stabiliser to provide directional stability at supersonic flight conditions, which leads to an increase in weight tail, and hence, the aircraft in general, and to an increase in drag.

Why balance is the key

Comparing the PAK-FA with the F-22 Raptor or F-35 Lightning II is a difficult task because most of the specs of these cutting edge aircraft are highly classified. Still, going by available data, the Russian aircraft doesn’t look as stealthy as the $420 million F-22.

The F-22’s stealth advantage doesn’t seem to worry the Russians. For, the PAK-FA embraces an entirely different combat philosophy where super maneuverability is considered a vital weapon. In contrast, the Americans have thrown all their eggs into the stealth basket, relying on near invisibility to strike at targets. The idea is to have “first look/first shot/first kill” air dominance capability. The aim – in reality hope – is to see the enemy first while avoiding detection.

However, hope is a poor substitute for preparation. The Russian view is that it never hurts to have dogfighting abilities. At some point stealth aircraft will have to close in for the kill and that’s when a knife fight is inevitable. That’s also when super maneuverability comes into play. Slow, ponderous and poorly armed stealth aircraft such as the F-35 are likely to be clubbed to death in a fight with the PAK-FA.

Plus, new radars are on their way which can detect stealth aircraft. At any rate stealth is not really an invisibility cloak as the American manufacturers and war planners are pitching it. The 1999 downing of the American F-117 stealth fighter by a highly motivated and well-trained Serbian anti-aircraft battery was a huge slap in the face of the American stealth industry.

The Serbians used a 1960s vintage – yet highly advanced – Russian S-125 Neva/Pechora surface to air missile conjointly with a P18 metre band radar. They were able to bring down the F-117 within 18 seconds of detection – a stark example of the vulnerability of stealth aircraft.

It will take the wars of the future to deliver the verdict on which philosophy is better – total stealth or the Russian insistence on super maneuverability. In the meantime, Russian and Indian Air Force pilots can’t wait to get their hands on what promises to be a fighter pilot’s dream.

They’ll have to wait a bit longer: according to the Russian National Armament Programme, 60 PAK-FA fighters will be delivered between 2016 and 2020.

 

[sferrin]

"Slow, ponderous and poorly armed stealth aircraft such as the F-35 are likely to be clubbed to death in a fight with the PAK-FA."

Wow, is this stupidity still being peddled? : PAK-FA doesn't have to out maneuver an F-35, it'd have to out maneuver an AIM-9X or ASRAAM. Good luck.

 

[flanker]

0.1 - 1 m^2 seems significantly worse than either the F-22 or F-35. What's a Super Hornet's?

1: Why is F-22's RCS "fixed" at around 0.001m^2? (a: because that is absolutely the lowest RCS for it, directly from front, at perfect frequency)
2: Why is T-50's number "fluctuating" between 0.1-1m^2?

PS: Or run the relevant 0.1-1 part through google translate:

http://www.fips.ru/cdfi/fips.dll/ru?ty=29&docid=2502643

 

[quellish]

1: Why is F-22's RCS "fixed" at around 0.001m^2? (a: because that is absolutely the lowest RCS for it, directly from front, at perfect frequency)

That probably has more to do with comments attributed to USAF a few years ago about the RCS of the F-22 ("size of a marble") and F-35 ("size of a golf ball").
http://www.strategypage.com/htmw/htairfo/articles/20051125.aspx
I've never seen the *actual* USAF statement this is attributed to. From those two statements people figured that a marble is 0.001m2 and that is -40dbsm, therefor potato.

 

[Trident]

0.1 - 1 m^2 seems significantly worse than either the F-22 or F-35. What's a Super Hornet's?

It rather depends on how the calculations are done doesn't it?

What would be the point of them stating a number if they weren't comparing apples to apples?

Didn't they give the F-22's RCS when evaluated on the same basis as 0.3m² or something like that? So they did state the number in order to make an apples to apples comparison, but obviously based on different standards, so they supplied a converted benchmark themselves.
If we are to believe that a clean Eurocanard or Super Hornet have a RCS in the 0.1 - 1m² ballpark (as the manufacturers claim they do) it seems implausible to assume the T-50 (with greater attention to shaping such as planform alignment etc.) would not better that performance.

 

[Trident]

"Slow, ponderous and poorly armed stealth aircraft such as the F-35 are likely to be clubbed to death in a fight with the PAK-FA."

Wow, is this stupidity still being peddled? : PAK-FA doesn't have to out maneuver an F-35, it'd have to out maneuver an AIM-9X or ASRAAM. Good luck.

Laser DIRCM, anyone?

 

[Avimimus]

Btw. One of the articles mentions four variants? I assume they mean the first batch of 60 aircraft vs. main production version, and the single vs. two-seat FGFA versions?

"Slow, ponderous and poorly armed stealth aircraft such as the F-35 are likely to be clubbed to death in a fight with the PAK-FA."

Wow, is this stupidity still being peddled? : PAK-FA doesn't have to out maneuver an F-35, it'd have to out maneuver an AIM-9X or ASRAAM. Good luck.

Laser DIRCM, anyone?

Well - if we are going there at all: - BVR combat works best if you have speed and supersonic manoeuvrability. The bigger issue is really simpler: Who is better a disengaging? It is hard to think of any instance in the history of air combat where the ability to pick the engagement wasn't more important than the actual characteristics of the aircraft. So, even if the PAK-FA doesn't have 'look first shoot first' it may have 'shoot first, scoot first' capability.

 

[flanker]

That probably has more to do with comments attributed to USAF a few years ago about the RCS of the F-22 ("size of a marble") and F-35 ("size of a golf ball").
http://www.strategypage.com/htmw/htairfo/articles/20051125.aspx
I've never seen the *actual* USAF statement this is attributed to. From those two statements people figured that a marble is 0.001m2 and that is -40dbsm, therefor potato.

I have seen marble analogy being mentioned outside of USAF. But it might simply be a "memo" the person got, so that that is the "politics" or RCS statements. But if it is 0.01 or 0.000001 or 0.0000000000000001 is besides the point. Point is that F-22's number is always given for absolute minimum RCS.

T-50's 0.1-1 m^2 isn't the absolute minimum, which is clearly stated in the patent with one single word. Hopefully sferrin will not avoid my question as it is very straight forward.

 

[sferrin]

That probably has more to do with comments attributed to USAF a few years ago about the RCS of the F-22 ("size of a marble") and F-35 ("size of a golf ball").
http://www.strategypage.com/htmw/htairfo/articles/20051125.aspx
I've never seen the *actual* USAF statement this is attributed to. From those two statements people figured that a marble is 0.001m2 and that is -40dbsm, therefor potato.

I have seen marble analogy being mentioned outside of USAF. But it might simply be a "memo" the person got, so that that is the "politics" or RCS statements. But if it is 0.01 or 0.000001 or 0.0000000000000001 is besides the point. Point is that F-22's number is always given for absolute minimum RCS.

T-50's 0.1-1 m^2 isn't the absolute minimum, which is clearly stated in the patent with one single word. Hopefully sferrin will not avoid my question as it is very straight forward.

Wasn't "avoiding" your question. Didn't seem worth responding to as you don't have any evidence that the F-22's numbers "area always given for absolute minimum RCS".