Advanced Medium Combat Aircraft (AMCA)

AMCA Scale Model at Aero India 2013. Photo © Copyright: Vijainder K Thakur

Introduction

ADA will complete a feasibility study on the AMCA - a 19-20 ton category fifth generation fighter that will feature stealth including an internal weapon bay - by the end of FY 2011.

The AMCA is being designed as an affordable fighter with swing role capability to meet the requirements of the IAF post 2020.

The aircraft will incorporate advanced technologies like super maneuverability, super cruise, stealth, state of the art sensor suite with fusion.

Medium Fighter, F-35 Analog

PS Subramanyam, programme director at the ADA, told Flight magazine during Aero India 2011 that the AMCA will be a 20t aircraft with a 1,000km range, fitting between the 10t, 500km range of the Hindustan Aeronautics Tejas, and the 30t, 1,500km range of the fifth generation fighter aircraft (FGFA).

The AMCA is being pitched as an analog of the F-35 Lightening, with the FGFA being an analog of F-22 Raptor.

The MCA will be a single seat fighter. A two seat version will be developed, but primarily as a trainer.

Sixth Generation Fighter Features

Speaking to The Hindu on November 25, 2011, ADA Chief P.S. Subramanyam said that since AMCA first flight was still seven years away it would be possible to incorporate some 6th generation combat aircraft features into it.

The AMCA would likely take 10 years before being ready for production as a replacement for MIG-29 and Mirage fighters.

Sixth Generation features include improved range, persistence, situational awareness, human-system integration and weapon fit to counter enemy anti-access/area-denial measures such as electronic attack, passive detection, cyber attack and directed energy weapons.

Payload

In February 2011, Air Chief Marshal Pradeep Vasant Naik said the MCA will have a payload capability of more than five tons.

Here are some photos of the AMCA concept displayed at Aero India 2011 by ADA.

Air-Air Combat Capabilities

Long Range Combat

Low Radar Signature

Extended detection range and targeting

Supercruise

Supersonic weapon release

Short Range Combat

Low IR signature

Thrust Vectoring

High AOA controllability

All aspect missile warning system

Air-Ground Capabilities

Stealth Missions

Suppression of Enemy Air Defense (SEAD)

Precision strike

Special missions

Non Stealth Missions

Maritime strike

Sensor Suite

AESA radar

IRST

Weapon Suite

BVR Missile

Close Combat Missile

JDAM

PGM

Survivability

Stealth

Electronic Warfare

Features

Shaping for Low Observability (LO)

Internal Weapons

Signature Control

Integrated Modular Avionics

Situational Awareness

Data Fusion

Future Missiles

Stand-Off Weapons

Precision Weapons

Vehicle Management

Advanced Sensor

Net Centric warfare

Appropriate EW

Design Evolution

ADA first displayed a wind tunnel model of the Advanced Medium Combat Aircraft (AMCA) twin engine fighter concept at Aero India 2009.

AMCA Model on display at Aero India 2009

The concept displayed at Aero India 2011 was not a wind tunnel model and differed from the 2009 design.

AMCA concept displayed at Aero India 2011

The scale model displayed at Aero India 2013 differed from the 2011 design and was wind tunnel tested.

AMCA scale model displayed at Aero India 2013

According to ADA, the MCA will have "serpentine-shaped" air intakes, internal weapons bays, and advanced radomes to increase its stealth features. Radar-absorbing composites and paints will supplement the design.

AMCA's Evolving Design Features

ADA hasn't completely frozen the design of the Advance Medium Combat Aircraft (AMCA), but the design has matured to a stage where ADA expects to make only small tweaks.

The design displayed as a scale model at Aero India 2013 has been validated for its reduced IR and Radar signature at a DRDO facility in Jodhpur. The aerodynamic characteristics of the design have been checked out in wind tunnel.

ADA is confident that the first prototype of the AMCA will be flying before the end of the decade.

The following discussion on AMCA's evolving design features are based on IDP Sentinel's discussion with a senior ADA official from the AMCA team during Aero India 2013.

Stealth Characteristics

The AMCA design is optimized for reduced signature, not maximized stealth.

The aircraft is not shaped for all aspect stealth, like the US Raptor (F-22) or the Chinese Chengdu J-20. Instead, shaping is optimized to minimize frontal Radar Cross Section (RCS).

The AMCA blends stealth with maneuverability, while keeping costs affordable. It represents an affirmation of the design philosophy that guided the development of the the Lightning 2 (F-35) and the PAK-FA.

ADA has done all that is theoretically possible to reduce the radar signature from the front, as is the case with the Raptor, Lightening 2, J-20 and the PAK-FA. A head on air-to-air missile threat is the most potent because of the limited reaction time available to a pilot for evasive measures (chaff, flares) and maneuvers, with the threat closure rate being a sum of the velocity vectors of the hostile missile and the defending aircraft.

Frontal Low Observability (LO) will give the IRST equipped AMCA the ability to close in to within lethal range of enemy aircraft while avoiding detection.

The AMCA is not heavily optimized to evade radar detection from the side. It will rely more on evading and spoofing ground radars to avoid tracking as is the case with other contemporary stealth aircraft.

ADA has made little attempt to reduce the radar signature of the aircraft from the rear, relying almost entirely on a reduced IR signature instead. A reduced RCS from the rear is difficult to achieve without very advanced engine technology represented by shaped exhaust nozzles as in the case of the Raptor, or a compromise on performance.

An air-to-air missile threat from the rear is comparatively less potent than a head on threat because the pilot has more time to react, with the threat closure determined by the differential in the velocity vectors of the aircraft and missile.

Single or Twin Seat

Despite a near frozen design, ADA isn't yet sure whether the fifth generation aircraft is going to be single or twin seater!

The scale model displayed at Aero India 2013 was certainly a single seater, like the scale models displayed earlier at Aero India 2011 and Aero India 2009.

A pamphlet distributed by ADA at the 2013 show made no mention of the number of aircrew.

However, an animation video displayed during the show mentioned that the aircraft would accommodate a "pilot associate to reduce pilot work load."

The IAF's preference for twin seat fighters is well known. The service believes that the complexity of the sensors and weapons suites fitted on modern fighters can optimally be managed by a crew of two, not one. The Su-30MKIs seats a Weapon System Operator (WSO), as would the Rafale MMRCAs to be inducted into the IAF.

With aerial refueling, modern fighters can stay airborne for as long as 7-10 hours, a duration that is too taxing for a one man crew.

ADA is pitching the AMCA to the IAF as a single seater, but is prepared to redesign in case of the unlikely scenario that the IAF sticks to its twin seater preference.

Usually fitting a second seat in a fighter aircraft results in no penalty other than reduced range, since space for the second seat is made by reducing fuel capacity. Aircraft combat performance remains unaffected.

In the case of a stealth fighter, fitting a second seat is more complicated. Though performance still remains unaffected, there is inevitably a change in the aircraft's stealth characteristic because of a change in RCS.

The RCS can be optimized for either single or twin seat configuration, with a single seater likely to be the stealthier design.

With good reason, the Raptor, Lightening 2 and the PAK-FA are all single seaters.

ADA acknowledges that a single crew AMCA may not be able to fly to the limit of its endurance, but points out that rarely does a wartime mission require a pilot to fly more than a couple of hours. This is especially true of India whose potential enemies are its neighbors.

Under the circumstances, it makes little sense to dilute the stealth characteristics of the AMCA to accommodate a second crew, says ADA.

Will it Have Thrust Vectoring

According to ADA, the AMCA Advanced Medium Combat Aircraft (AMCA) will be super maneuverable but at this stage it is not clear if it will use thrust vectoring.

A DRDO pamphlet distributed at Aero India 2013 significantly did not claim the aircraft would have thrust vectoring, or even be super maneuverable.

However, an animation video displayed at the event listed super-maneuverability and thrust vectoring among the aircraft features.

The scale model of the AMCA displayed at Aero India 2013 had unshaped and fixed nozzles. As mentioned above, ADA is passing on rear aspect RCS reduction, relying exclusively on IR suppression for low observability (LO).

As to the non thrust vectoring nozzles, ADA is yet to make a call on thrust vectoring for the AMCA, because super-maneuverability can be achieved without thrust vector control (TVC) like in the F-35 Lightening 2.

ADA will wait for the IAF to lock its maneuverability requirements before making a call on thrust vectoring, opting for it only if the reserve of power in the new engine being developed for AMCA with foreign collaboration proves inadequate to meet IAF requirements.

While the Russians favor thrust vectoring for super-maneuverability, western countries are continuing to rely on high thrust to weight (T/W) ratios despite possessing TVC technology.

High T/W ratio is a better option for sustained high maneuverability because it doesn't lead to rapid bleeding of energy levels.

AMCA Engine

As has been widely reported, the AMCA will be powered by a new engine that the GTRE plans to develop with the help of one or more foreign consultants, Snecama being one of them.

The current version of the Kaveri, which is undergoing flight certification, is limited to 81 kN of thrust with after burning because turbine blade manufacturing technology available with GTRE and HAL doesn't allow for turbine entry temperatures in excess of 1700 K.

High temperatures weaken the blades and make them more susceptible to creep failures, as also corrosion.

Snecama technology will help GTRE add a lot more thrust to the new engine. GTRE may additionally collaborate with Russia for thrust vectoring technology, depending on IAF requirements.

Use of Canard

ADA's decision to not use canards was a bold one. Europeans fighter aircraft manufacturers are heavily into canards – the Eurofighter, Rafale and Gripen all have them.

The Russian MiG I.42 super cruise fighter developed in parallel with the T-50 also featured canards.

Canard wings are associated with better supersonic performance and maneuverability, and the combination of good stealth and good supersonic performance is essential for penetrating enemy defenses safely. Everything else about fifth generation fighters – super maneuverability, sensor fusion, etc. is secondary.

When the Chinese unveiled their Chengdu J-20 heavy stealth fighter in January 2011, it too had canards!

The J-20 is widely believed to be as stealthy as the F-22 from the front, and it should have as good supersonic performance as the F-22.

China's use of canards in its stealth aircraft rattled ADA.

ADA acknowledges that China is well ahead in the game of fighter aircraft design in general and stealth aircraft design in particular. One good reason being, the Chinese programs are very heavily funded as compared to ADA's.

China's Chengdu worked with canards while developing the J-10, but their use of canards on the stealthy J-20 made ADA scientists wonder if they had made the wrong decision by not incorporating canards into the AMCA design.

ADA must have taken solace from the fact that the Americans have dismissed canard fighters with some disdain, and stuck with non canard fighters. Both their stealth designs - F-22 and F-35 – are non canard and the F-22 has excellent supersonic maneuverability as well as stealth characteristics.

But then, America also has unmatched engine and signature suppression technology, which India doesn't.

ADA Design Vindication

When China unveiled its second stealth fighter, J-31 (F60), in late 2012 ADA's choice of a non canard design appeared to have been vindicated.

Developed by the Shenyang Aircraft Corporation, the medium weight J-31 has no canards. Clearly, the Chinese had their own doubts about canards.

The J-31, is modeled on the F-35 just like ADA's AMCA - medium weight and not very stealthy. However, the J-31 closely resembles the F-35, while the AMCA doesn't.

Indeed, there is a school of thought that China developed the J-31 using design files of F-35 stolen by hacking Lockheed computers.

No one doubts that like the LCA, the AMCA is a home grown solution.

A senior DRDO scientists associated with the AMCA project told IDP Sentinel that the ADA team is proud that they made the right choice at a very early stage.

Development Progress

On May 17, 2013, DRDO Chief VK Saraswat refuted earlier press reports that the AMCA project had been shelved.

He told the PTI, "Currently, it is in the design stage. A good work is being done. After this we will go to government which will take a year's time'. There are three major technologies along with lot of associated technologies which have to be developed. DRDO was developing this."

He added that no decision had been taken so far on shelve the project by DRDO, HAL or Defense ministry.

Some of the new technologies that ADO wishes to incorporate in the AMCA include a FBW control system with photonic interface to reduce the length of wires (fly-by-light).

DRDO also plans to develop a completely new engine with foreign collaboration for the AMCA.

On April 21, 2013, The Sunday Standard reported quoting an MOD source that the AMCA project has been put on hold in order to get ADA to focus entirely on the LCA project.

MOD believes that the MMRCA and FGFA projects will adequately cover the gaps that were to be filled by the AMCA.

The AMCA project could possibly be revived at a later stage.

On May 10, 2013, The Financial Express carried the report again.

Past Progress Reports

PS Subramanyam, programme director at the ADA told Flight magazine during Aero India 2011:

"The MCA will be in flight trials by end of the decade, and it will be inducted by the middle of the next decade."

Speaking at Aero India 2009, M. Natarajan, DRDO chief and scientific adviser to the defense minister said:

"Even though we don't have a project as yet, we have started conceptual work on our own for the Medium Combat Aircraft. I will not call it Fifth Generation Aircraft but it is very close provided we are able to incorporate more stealth features."

The project was initiated to capitalize on the knowledge and expertise gained from the work put into the LCA project. The Air Force has shown interest in the project.

"I am happy to say some very preliminary discussions have started with the Air Force," Natarjan said. "They are showing considerable interest and this is linked to the kind of developments we could demonstrate in avionics, electronic warfare and our own radar development technology particularly for the AWE&C," he added.

Funding For Two Technology Demonstrators and Seven Prototypes

$2 billion funding sought for 2 technology demonstrators and seven prototypes with first flight by 2017

In November, 2010, Business Standard reported that ADA has sought a $2-billion (approximately Rs 9,060 crore) fund from the Indian government for the development of AMCA.

“We have just started working on this fifth-generation aircraft, for which we had already received sanctions to the tune of Rs 100 crore. The way the government is cooperating, I am able to say that we will receive the funding ($2 billion) in the next 18 months,” PS Subramanyam, program director (combat aircraft) and director of ADA, told Business Standard.

“The $2-billion fund will initially be utilized to develop two technology demonstrators and seven prototypes. The first flight test is expected to take place by 2017,” he said on the sidelines of the Aviation Conclave 2010 in Hyderabad.

According to Subramanyam, the AMCAs will bridge the gap between the Tejas and Su-30MKI class heavy fighters. With Russia and the US focusing on fighters in the 30-35 ton category, there was market space for a 20 ton aircraft.

“Though the AMCAs were primarily being designed to meet the requirements of the Indian Air Force, we are contemplating rolling out a new variant for the Indian Navy as well,” he said,

Sixth Generation Fighter

Subramanyam also told the press that ADA is poised to commence research and development on a six-generation AMCA aircraft shortly.

IDP Sentinel

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