With the selection of GE F414 engine, it is clear now that the GTRE-Snecma proposal would in no way militate against the selection of the engine for the Tejas Mk II

On October 1, 2010, General Electric Company (GE) of USA with its offer of the GE F414 afterburning engine, emerged as the lowest of the two bidders in the race for the selection of an engine to power the light combat aircraft (LCA) Tejas MK II. The company has now been invited to negotiate a contract to provide the Indian Aeronautical Development Agency (ADA) with 107 F414 engines. Although trade deals worth billions of dollars signed during the US President Barack Obama’s recent visit to India has raised the hopes of GE to new heights, the final word on the contract is yet to be said.

Selection of GE for further negotiations has, however, put an end to the prolonged debate and the ensuing uncertainty on the progress of the Tejas Mk II programme. But it could raise a few queries as well. Competing with GE for the $822 million (Rs. 3,700 crore) tender for a total of 107 engines floated by the Indian Defence Research and Development Organisation (DRDO), was the Eurojet Turbo GmbH, a European consortium. It comprises four companies of Europe namely Avio of Italy, ITP of Spain, MTU of Germany and Rolls-Royce of UK.

Background

The programme to design, develop and manufacture indigenously a light weight fighter aircraft designated as the light combat aircraft (LCA) and subsequently rechristened as “Tejas”, was launched in 1989 with a view to replace the ageing fleet of MiG-21 aircraft of the Indian Air Force (IAF). The Indian aerospace industry at that time did not have the capability to produce an aero engine to power the LCA and there was no option but to look for a solution abroad. The choice fell on the GE F404 after burning turbofan engine of weight lower than other contemporary engines. However, the GE F404 was capable of delivering dry thrust of only 53.9 kilonewtons (kN) and 82 kN with afterburner, which was considerably lower than the 100 kN desired by the IAF. The decision to employ the GE F404 engine was regarded as an interim measure and was to be limited to the prototypes in the development phase. With the ultimate aim of total indigenisation of the LCA, as a long-term solution, an ambitious programme to develop a fourth generation engine called the Kaveri was sanctioned in 1989 and was assigned to the Gas Turbine Research Establishment (GTRE), a facility under the DRDO. Intended to power the first batch of production models of the Tejas, the cost of the project was estimated at launch to be Rs. 382.81 crore and was to be completed by the end of 1996.

However, 14 years after the initially stipulated date of completion and investment of nearly Rs. 3,000 crore, the Kaveri project was formally delinked from the LCA programme in September 2008. ADA, however, continued with the Tejas programme with the underpowered GE F404 and a somewhat dissatisfied IAF rather reluctantly ordered 40 aircraft in the first batch to constitute the first two squadrons. There was an imperative need to find a new power plant close to the required level of performance to give the IAF sufficient confidence to place orders for another 100 aircraft that would meet the stipulated performance requirements. Thus began the search for a new engine.

The Contenders

GE responded to the request for proposal (RFP) floated earlier this year for the new engine with the offer of the GE F414-400, a derivative of the highly reputed and widely used GE F404. Employed on the Boeing F/A 18 Super Hornet and the Gripen from Saab of Sweden, the GE F414 has established a credible record of reliability. Incidentally, F/A 18 and the Gripen are both contenders for the mega deal for 126 medium multi role combat aircraft (MMRCA) tender for the IAF which is also expected to be finalised in a year or so from now. The GE F414 engine is fitted on naval variants of combat aircraft.

Employing the latest technologies and featuring a dual channel full authority digital engine control (FADEC), the GE F414 operates at a pressure ratio of 30:1, which is significantly higher than the contemporary engines. While the high pressure ratio provides higher level of efficiency, it also produces greater heat stress on the engine. To cope with this, the GE F414 employs single crystal low-density blades fused with disks. Called “blisks”, these are lighter but stronger compared to conventional blade designs. With reheat, the GE F414 is capable of delivering a maximum thrust of 98 kN which is only marginally short of the qualitative requirements spelt out by the IAF. Heavier by 50 kg compared to the GE F404, the GE F414 has an identical maximum diameter which is 35 inches and is of a similar length of 157 inches. However, its inlet diameter is 32 inches as against 31 inches of the GE F404.