Having woken up to the progress made by countries like China in developing indigenous engines for military aircraft late, the Union government has directed the Defence Research and Development Organisation (DRDO) to fast-track the ‘Kaveri’ engine project conceived as the power plant for the Tejas Light Combat Aircraft (LCA). Much of the criticism for LCA Tejas can be contributed to Kaveri engine. The indigenous engine development somesaulted many target dates, that it was finally jettisoned from the LCAs project officially in september,2008 and is generally written off as a 25-year, Rs. 2,100-crore drain on resources. But now it looks set to resume where it left off two years ago and complete the last lap of its development. GTRE (Gas Turbine Research Establishment , a lab under the DRDO in Bangalore is the developer of the kaveri engine) is now running two separate successor engine programmes, the K9+ programme and the K10 programme.

In brief about kaveri...

Indigenous development of Kaveri Engine to power the Tejas aircraft was sanctioned on March 30, 1989 at a cost of Rs.382.81 Cr with a PDC of December 31, 1996. The cost of the project was revised to Rs.2839.00 Cr with PDC of December 2009. Further continuation of Kaveri project beyond the PDC has been approved by the Government within the sanctioned cost and scope.

The Kaveri is a low-bypass-ratio (BPR) afterburning turbofan engine featuring a six-stage core high-pressure (HP) compressor with variable inlet guide vanes (IGVs), a three-stage low-pressure (LP) compressor with transonic blading, an annular combustion chamber, and cooled single-stage HP and LP turbines. The development model is fitted with an advanced convergent-divergent ("con-di") variable nozzle, but the GTRE hopes to fit production Tejas aircraft with an axisymmetric, multi-axis thrust-vectoring nozzle to further enhance the LCA's agility. The core Turbojet engine of the Kaveri is the Kabini.

The general arrangement of the Kaveri is very similar to other contemporary combat engines, such as the Eurojet EJ200, General Electric F414, and Snecma M88. At present, the peak turbine inlet temperature is designed to be a little lower than its peers, but this is to enable the engine to be flat-rated to very high ambient temperatures. Consequently, the bypass ratio that can be supported, even with a modest fan pressure ratio, is only about 0.16:1, which means the engine is a "'leaky' turbojet" like the F404.

The DRDO has not fixed any time frame to fully develop the Kaveri Aero Engine for the LCA, Tejas.LCA, Tejas requires 90 kN thrust class engine to meet its operational requirement, whereas Kaveri Engine does not fully meet this requirement. Therefore, it has been decided to use variants of Kaveri Engine to power Unmanned Air Vehicle and also for marine applications.In a statement in Parliament on December 10, 2012, Defense Minister AK Antony confirmed that a Kaveri variant could be used to power the Indian Unmanned Strike Air Vehicle (USAV). On December 25, 2012, Business Standard reported that the decision to use the Kaveri as the USAV power plant was prompted by the engine's relatively good performance when operating without reheat.

During testing at the Gramov Flight Test Center, the Kaveri had demonstrated a dry thrust of 49.2 KN against a designed 51KN. With reheat the thrust deficit was substantial; 70.4 KN against the designed 81 KN.UCAVs use unreheated engines inorder to minimize their heat and noise signatures. Also, the thrust requirement for the USAV is more modest."Since the USAV will weigh less than 10 tonnes, the Kaveri’s 50 KN will suffice. And, with the afterburner removed, we would significantly reduce the weight of the Kaveri," a top DRDO scientist told the Business Standard.

In July 2008, DRDO tested a marine version of the Kaveri engine on the Marine Gas Turbine test bed at Naval Dock Yard, Vishakapatnam. The Indian Navy facility is capable of testing Gas Turbines upto 25 MW of shaft power through a reduction gearbox and a water brake dynamometer.

The Kaveri derivative, called the Kaveri Marine Gas Turbine (KMGT), was tested to its potential of 12 MW at ISA SL 35°C condition which is the requirement of Indian Navy for propelling the SNF (Rajput) class of ships.With this development, India will become self-reliant in the technology of gas turbines for ship propulsion. This will put India in the elite club of Marine Gas Turbine designers e.g., USA, Russia, UK and Ukraine.

The revival..

On October 1st, 2013 DRDO director general (aeronautics) K Tamilmani told reporters that that the organisation and Gas Turbine Research Establishment (GTRE), which developed the engine, have been asked to submit a detailed report of funds required to revive the project.China recently involved 11 universities to help develop its Shenyang Liming ‘WS-10’ engine. Earlier, it was kept on the backburner after failing to meet airworthiness requirements and had been replaced with a Russian engine on Chinese fighters.

GTRE director C P Ramanarayan said that the Kaveri project, worth Rs 2,108 crore, will now be revived. Next year, the GTRE plans to show the engine’s performance first on an Il-76 plane and then as the second engine fitted on a twin-engined fighter like MiG-29. It would be tuned to certification standards.

“When we do that, we will have the first indigenous [aero]engine with proven and certified performance for exploitation” — meaning it would be rendered suitable for fitting on future Indian-made military or passenger aircraft — Dr. Ramanarayanan told The Hindu later.

Dr. Tamilmani said a ready engine would precede an indigenous aircraft programme, a model followed worldwide. The aero engine has been a vital but missing link in the country’s military aviation, which has to buy them from foreign makers at huge costs. Each aircraft needs to replace its engines three or four times during its lifetime.

A 2011 survey by the GTRE estimated that this decade, India could spend Rs. 1.8 lakh crore to buy engines plus another Rs. 4 lakh crore for their upkeep. The DRDO scientists admit to slip-ups and lost opportunities.

In a separate activity, military plane maker Hindustan Aeronautics Ltd is developing engines for its helicopters and trainer aircraft by 2018.