Which Engine Will Power The Tejas?

Late next month, a critical competition process kicks off for the selection of an alternate power source for the Indian Light Combat Aircraft (LCA Tejas). After pre-bid feasibility studies that were conducted through much of 2008, the Aeronautical Development Agency (ADA) -- the umbrella body of agencies involved in the LCA's development -- sent out Requests for Proposal (RfP) to Ohio-based GE Aviation for the F-414-400 and Hallbergmoos (Germany) based Eurojet Turbo GmbH for the EJ200. Both companies are required to submit their technical proposals by October 12. Technical evaluations of the engines will be complete by the end of the year, though these are planned to be truncated since a lot of technical work has been pre-completed during the feasibility studies. The technical evaluation will be followed by a full schedule of trials. As you might remember, it was the Defence Ministry's Aeronautics R&D Board Propulsion Panel, headed by ADA Project Director (Propulsion Systems) Dr KVL Rao, which recommended in July last year that the LCA programme rapidly begin a process to choose between the two mentioned engines to power upto 100 fighters (with an option to power 60 more). It was after his recommendations were submitted to the ADA that feasibility studies were begun with both GE and Eurojet for their respective turbofans.

Modifications are a non-issue as of now, with both GE and Eurojet declaring that their engines can fit in the LCA's fuselage. A limited number of engines will be bought direct from the winning contender, while the rest will be license-built at HAL's engine factory in Koraput, Orissa. With all options exercised, the deal could be worth close to $600-million.

The obvious tie-in with the medium multirole combat aircraft (MMRCA) competition is the lifeblood of the Tejas new engine bid. While the EJ200 powers the Eurofighter Typhoon, the F414 powers Boeing's F/A-18E/F Super Hornet as well as the JAS-39 Gripen IN.

According to IAF sources embedded with ADA, on paper, both engines "just about" meet what the air force wants and needs from the LCA in terms of thrust. Having established that, what are the possible criteria of selection, if one were to put aside political and/or other considerations?

Point 1, virtually everyone I've spoken to at the ADA and air force believe that the engine that meets the new thrust compliance bar and fits the Tejas with the least amount of engineering, fabrication or modification will be selected. Both engines say they meet the maximum thrust requirements demanded by the IAF. The American F-414-400 is physically similar, if not identical, to the F-404 that currently powers the Tejas, and is, remember, a technological derivative of the same. Therefore, it stands to reason that ADA believes the people at GE when they say the F-414 is a spot-on fit without any tinkering. Similarly, based on information gleaned from the feasibility study, Eurojet boss Hartmut Tenter told Flightglobal earlier this year that "the EJ200 fits perfectly into the same hole." Ok.

Point 2, weight issues, which won't be taken, um, lightly. The F-414-400, at 1,109-kgs is approximately 120-kgs heavier than the EJ200.

Point 3, the F-414-400 has a stated maximum thrust of 98kN, more than the EJ200's 90kN, even though both technically meet the IAF's requirement for a 90kN turbofan. Will the extra thrust that the American engine apparently offers be enough reason to ignore the 120-kgs of additional weight that it brings to the competition? Maybe.

Point 4, the folks at ADA have had a great amount of experience working with GE on the LCA programme, so the American firm is well-versed with the rough and tumble of the IAF's qualitative requirements. Working with a firm that is already "in the picture" about your requirements is an intangible consideration, but a consideration nevertheless.

Point 5, if the IAF's mantra for lowering inventory type is taken even a bit seriously, then the outcome of this competition could bring a great amount of influence to bear on the far more lucrative MMRCA competition. This alone could give the government a huge amount of leverage either way, though it could also slow things down significantly to the detriment of the LCA programme.

The selection process begins next month. Stay tuned.

Photo of Tejas ┬ęCopyright Kedar Karmarkar

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