HAL joins DRDO in building 5th-gen advanced combat aircraft

The Indian Air Force (IAF) is already flying the first 32 Tejas Mark 1 fighters, and an order for 83 Tejas Mark 1A has been placed on Hindustan Aeronautics Ltd (HAL). Meanwhile, there have been important development breakthroughs in the following two fighter programmes: the Tejas Mark 2 and the 5th-generation Advanced Medium Combat Aircraft (AMCA).

The IAF has accorded the Tejas Mark 2 its “comprehensive design review” (CDR), which means its design has been found viable and the manufacture of its first prototypes cleared.  The AMCA is one step behind, with its preliminary design review (PDR) done last December. It was anticipated that its CDR would also be completed this December, but it now more realistically targeted for end-2022.

Girish Deodhare, who heads the Aeronautical Development Agency (ADA) – the Defence R&D Organisation (DRDO) agency that oversees the Tejas and AMCA programmes – told Business Standard that the AMCA’s stealth shaping had been completed, its design is now mature and its internal systems are laid out. The accord of the CDR next year would clear the way for metal cutting – the symbolic start of constructing a flying prototype.

In an exclusive visit by Business Standard to HAL, designers stated: “The AMCA’s first flight is targeted for 2024-25. We plan to build five prototypes for a flight-testing programme that would take about four years. By 2028-29, we plan to begin series manufacture.”

Stealth fighters – such as the AMCA – play a crucial role in a war’s opening stages. Taking advantage of their invisibility to radar, they fly deep into enemy airspace and strike enemy radars, air bases and control centres in order to obtain air superiority. This opens the door for “non-stealthy” fighters like the Sukhoi-30MKI, Jaguar and Mirage 2000 to penetrate enemy airspace and strike enemy targets such as roads, railways, airfields, depots and ground forces without incurring heavy casualties.

For example, in a war with China, India’s opening salvos would consist of AMCA strikes deep into China, to destroy its rail and road links with Tibet and isolate the People’s Liberation Army (PLA) divisions on the Sino-India border.

A 5th-generation fighter like the AMCA is able to defang enemy air defences because of four advanced capabilities: It is “stealthy”, or near-invisible to enemy radar, and it can “supercruise”, or fly faster than the speed of sound without engaging its engines’ fuel-guzzling afterburners. Third, its advanced avionics and sensors, coupled with artificial intelligence and network-centric operations enhance the pilot-aircraft interface, allowing a single pilot to both fly and fight the aircraft. Fourth, it can detect and engage targets from long distances, outranging its adversaries.

Stealth remains a 5th-generation fighter’s key attribute. It is shaped to scatter radar waves, rather than being detected by reflected waves. Special non-reflective materials and coatings further reduce radar reflectivity. In stealth mode, a 5th-generation fighter conceals its fuel and weapons in an internal bay, since carrying them under its wings, as conventional fighters do, creating protrusions that reflect radar wave and compromise stealth.
According to HAL chairman, R Madhavan, the AMCA will have an “all-up-weight” (AUP) of 20 tonnes in stealth mode, when it would carry just one-and-a-half tonnes of weaponry concealed in internal weapon bays. However, in “non-stealth mode”, another five tonnes of fuel of armaments could be carried on external stations, under its wings.

When functioning as a deep penetration bomber, the AMCA would carry up to 6.5 tonnes of fuel in internal tanks. Its operating range is secret, but a rough calculation would indicate an ability to strike targets 1,000 kilometres inside enemy airspace and return to base.
Stealth is easily compromised, such as while releasing weapons onto a target. This requires weapons bay doors to open, release weapons and close again within 1.5 seconds. During this period, the fighter is more easily detected by enemy radar.

In “non-stealth” mode, the AMCA would carry much of its weapons load on its six external, under-wing stations. That would free up internal fuel tanks to carry an additional 1,200-1,300 litres of fuel, increasing its capability as a potent long-range, non-stealthy bomber.

However, given the AMCA’s tactical value and its cost, it is likely to be reserved mainly for stealth missions, using armament carried on four weapons stations in its internal bays.

Alongside the engineering of a stealthy profile, the AMCA programme’s biggest challenge is to develop a new, “super-cruising” engine. Until a suitable indigenous engine is developed, the AMCA will be powered by twin General Electric (GE) F-414 engines – which, in single- engine configuration, will power the Tejas Mark 2.

However, even twin F-414 engines are not enough to make the AMCA super-cruise in all configurations. According to the ADA chief: “Each F-414 engine generates a maximum thrust of 98 KiloNewtons (KN), and in Indian climatic conditions that effectively degrades to 90 KN. We have calculated that an AMCA, with the configuration the IAF has specified, requires a thrust of about 220 KN (in Indian conditions) for super-cruising. That means we need twin engines, each generating 110 KN thrust in Indian conditions,” says Deodhare.

Such an engine remains elusive, even for China with all its ability to throw money and manpower at the problem. However, a group of DRDO laboratories, led by the Gas Turbine Research Establishment (GTRE), Bengaluru, is working to develop an AMCA engine. GTRE had managed to generate a maximum thrust of 83 KN with the Kaveri engine. Now the target is 50 per cent higher.

Former Defence Minister Manohar Parrikar had estimated the AMCA would cost about $4 billion to develop – with a major share going into the engine. In 2015, India set up a “joint working group” (JWG) with America to co-develop jet engine technology. In October 19, US Under Secretary of Defence Ellen Lord reenevealed the JWG had been scrapped since US export control laws safeguarded key technologies that the DRDO wanted.

With almost a decade of work and Rs 400 crore having gone into the AMCA, responsibilities are being reassigned. In 2020, HAL was given a larger share of the programme, including the responsibility for the entire structural design, less the centre fuselage.

The serial production of the AMCA was made over to HAL’s Aircraft Manufacturing Division, Nashik; which has so far been engaged in manufacturing the Sukhoi-30MKI. That order has been discharged in full.

However, the Niti Aayog has cleared a proposal to make over AMCA manufacture to a “special purpose vehicle” (SPV) that will include two private sector firms in partnership with ADA and HAL. Suitable private sector partners have not yet been identified.





Source:- Ajai Shukla/ Business Standard

Image Credit: Kunal Biswas

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