Tejas Light Combat Aircraft - Engine

The 'Achilles heel in the successful development of the LCA was the Kaveri engine. An important recommendation of the Aeronautics Committee, which was accepted by Government in 1969, was that Hindustan Aeronautics Ltd (HAL) should design and develop an advanced technology fighter aircraft around a proven engine.

Based on IAF 'air staff target' papers, HAL finally completed design studies for a Tactical Air support Aircraft in 1975 and it appeared that HAL would, after a lapse of twenty years, get down to developing a fighter. However, the selected ‘proven engine’ from abroad, could not be procured and the project fell through. HAL's design and development capability started to decline. Meanwhile, The IAF's requirement for an air superiority fighter (primary role) with air support/interdiction capability (secondary role) in the tactical battle area, continued.

The first prototype of LCA rolled out on 17 November 1995. Two aircraft technology demonstrators were powered by single GE F404/F2J3 augmented turbofan engines. Regular flights with the state-of-the-art "Kaveri" engine, being developed by the Gas Turbine Research Establishment (GTRE) in Bangalore, were planned for 2002, although by mid-1999 the Kaveri engine had yet to achieve the required thrust-to-weight ratio.

Following India's nuclear weapons tests in early 1998, the United States placed an embargo on the sale of General Electric 404 jet engines which are to power the LCA. The US also denied the fly-by-wire system for the aircraft sold by the US firm Lockheed-Martin. As of June 1998 the first flight of the LCA had been delayed due to systems integration tests. The first flight awaits completion of the Digital Flight Control Systems, being developed by the Aeronautical Development Establishment (ADE).

The indigenous Kaveri engine, under development by the Gas Turbine Research Establishment (GTRE) is slated for installation in a PV aircraft. Over 7,000 hours of ground testing of the core engine (Kabini) and four prototype Kaveri engines, together with flights in a Tu-16 test-bed aircraft would have been completed. Engine components have been produced by several manufacturing units, including HAL, where the exclusive Cellular Manufacturing Facility (CNC machining) was established in November 1988. A concurrent engineering approach has been followed to provide engines early in the LCA's flight development. Salient engine features include the 3 stage fan; 6 stage HP compressor with variable geometry IGV, I and II stators; annular combustion chamber; cooled single stage HP and LP turbines; modulated after-burner; fully variable, convergent-divergent nozzle; length 3490 mm; max diameter 910 mm; dry thrust 52 kN; reheat thrust 81 kN; thrust weight ratio 7.8.

During tests in 2004 at the State Institute for Aerodynamics Research, Moscow, the Kaveri engine failed during simulated high-altitude conditions. In 2005, the IAF ordered 40 Tejas aircraft with the American GE-F404 F2J3 engine. India signed a contract to buy 40 of the American engines General Electric, in addition to the 11 ordered for the initial development program of the LCA project. The DRDO's Gas Turbine and Research Establishment continued developing the Kaveri engine, however, if the engine is not delivered, the Tejas will use the American engines.

Defence Research and Development Organisation (DRDO) initiated a project for design and development of an Aero-engine in 1989 for requirements of combat aircraft. Since then, a considerable progress has been made in development of aero-engine. However, full objectives have not been achieved, like desired thrust. Hence, GE-F404 Engine was selected as the power plant for Light Combat Aircraft (LCA) Mk-I. LCA Mk-II requires a higher thrust class Engine, therefore, GE-F414 Engine was chosen as power plant for LCA Mk-II. Both engines are imported from M/s General Electric, USA. LCA Program (Mk-I & Mk-II) already went ahead with alternate engine (GE-F404 & GE-F414). Kaveri engine development program continued and dry variant which would power Indian Unmanned Strike Air Vehicle (IUSAV).

HAL ordered an additional 24 F404-GE-IN20 afterburning engines to power the first operational squadron of Tejas fighter aircraft for the IAF in February 2007. This order, valued in excess of $100 million, followed an initial 2004 purchase of 17 F404-GE-IN20 engines to power a limited series of operational production aircraft and naval prototypes. Based on the F404-GE-402, the F404-GE-IN20 is the highest-rated F404 model and includes a higher-flow fan, increased thrust, a Full Authority Digital Electronic Control (FADEC) system, single-crystal turbine blades and a variety of single-engine features. The F404-GE-IN20 succeeds F404-F2J3 development engines used for nearly 900 flights, cumulatively covering nine engines.

The F404-GE-IN20 engine took to the skies 20 June 2008, marking the start of flight-testing on India's Tejas Light Combat Aircraft (LCA) for the Indian Air Force. During the 44- minute flight, the F404-GE-IN20 engine demonstrated full aircraft system and instrumentation functionality, climbed to numerous mission altitudes, achieved Mach 1.1 speed and established the engine performance baseline for future flight-testing. "The engine has performed extremely well during all phases of testing, and we look forward to delivering the benefits of -IN20 power throughout the remainder of the rigorous program," said Tony Mathis, general manager of the F404/F414 program.

Testing was expected to continue into 2009 under the direction of the Aeronautical Development Agency (ADA), with three aircraft scheduled for flight in the third quarter of 2008. Testing would involve approximately 250 flights and assess aircraft systems and engine functionality. Delivery of initial production engines was earmarked to Hindustan Aeronautics Limited (HAL) later in 2008, where they would be prepped for aircraft installation. Flight testing follows a rigorous series of evaluations, culminating in generation of more than 19,000 pounds (84 kN) uninstalled thrust and completion of 330 hours of Accelerated Mission testing - the equivalent of 1,000 hours of flight operation.

On 01 October 2010 India's Aeronautical Development Agency (ADA) selected 99 F414 GE fighter jet engines to power the Mk II version of the Tejas Light Combat Aircraft (LCA) for the Indian Air Force. John Flannery, President & CEO, GE India said, "The LCA selection is a big step forward for GE and demonstrates our strong commitment to India. GE Aviation will supply the initial batch of F414-GE-INS6 engines and the rest will be manufactured in India under transfer of technology arrangement."

The F414-GE-INS6 is the highest-thrust F414 model and includes state-of-the-art technology to meet India's demanding Air Force and Naval requirements. Technical advances include a Full Authority Digital Electronic Control (FADEC) and added single-engine safety features. "We are extremely pleased with the ADA's decision and are confident India's technical expertise will help enhance the F414-powered LCA's mission superiority well into the 21st century," said Tony Mathis, general manager of Lynn Military Systems programs at GE Aviation.

This selection follows earlier orders of 24 F404 GE engines in 2007, plus an initial 2004 purchase of 17 F404 engines to power a limited series of operational production aircraft and naval prototypes. With more than one million flight hours, the F414 engine continues to exceed United States Navy goals for reliability and time on wing. To date, more than 1,000 F414 engines have been delivered, supporting more than 415 aircraft in the fleet.

Indian defense scientists were optimistic about the fate of an indigenous jet engine after a November 2016 consultancy agreement with a French company. The GTX-35VS Kaveri turbofan engine, developed by the state-owned Gas Turbine Research Establishment was originally meant to power the Tejas light combat supersonic aircraft. But it failed to produce sufficient thrust to power a fighter and eventually stalled because India lacked the expertise to make alloys that can withstand high temperatures while advanced nations were unwilling to part with the technology. India has been compelled to import engines from General Electric of the US to power the Tejas.

"Non-availability of raw materials, critical components, lack of infrastructure and test facilities within the country and non-availability of skilled / technical manpower in the field of aero-engine technology are some of the major reasons for non-completion of project within the time schedule," Manohar Parrikar, India's Minister for Defense, told the Upper House of Parliament. After months of negotiations, French firm Safran agreed to assist India in making the Kaveri engines flight-worthy. As Safran also makes engines for Rafale fighter jets, the Kaveri deal is part of the offset clause that requires the French firm to invest half of the Rafale deal in India.