India's fighter jet engine efforts get a big boost: Desi Kaveri engine clears key step in Russia, ready for integration with stealth UCAV ‘Ghatak’

India's Kaveri dry engine has completed high-altitude and flight trials in Russia, recording a peak dry thrust of 48.5 kilonewtons (kN) against its target of about 46 kN. Developed by the Defence Research and Development Organisation's (DRDO) Gas Turbine Research Establishment (GTRE), the engine is being developed for India's planned Ghatak stealth unmanned combat aerial vehicle (UCAV), a TOI report stated.

The Kaveri Derivative Engine is a non-afterburning version of the original Kaveri engine. It is designed for aircraft that do not require the additional thrust provided by an afterburner. The latest trials are an important step before the engine can move towards airworthiness certification and eventual integration with its intended platform.

Kaveri engine tested in Russia

The trials were conducted at two Russian facilities, the Central Institute of Aviation Motors and the Gromov Flight Research Institute. At the Central Institute of Aviation Motors, the engine was tested under conditions designed to replicate high-altitude flight. Such conditions involve major changes in air pressure and temperature as altitude increases.


The engine was subsequently tested in flight at the Gromov Flight Research Institute. For this phase, the Kaveri was fitted to a modified Ilyushin Il-76 flying testbed. One of the aircraft's standard engines was replaced with the Kaveri so that engineers could assess its performance during actual flight without installing it on its final aircraft. The trials covered different ambient pressures, Mach numbers and thrust requirements. Testing was carried out both on the ground and during flight.

Engine records 48.5 kN thrust

The Kaveri derivative was designed to deliver around 46 kN of dry thrust. During the latest trials, it reached 48.5 kN. The result gives the engine some margin over its stated thrust target. However, the trial result does not by itself mean that the engine is ready for operational deployment.

The test data will be examined by the Centre for Military Airworthiness and Certification. The engine will still have to receive airworthiness clearance, while certification and integration with the aircraft remain to be completed.

Kaveri programme began for Tejas

The Kaveri programme dates back to 1986, when India began work on an indigenous engine for the Light Combat Aircraft Tejas. The programme was formally sanctioned in 1989, with 1996 set as the original completion target. The initial engine was planned as a low-bypass turbofan with an afterburner. Its development included work on the compressor, combustion chamber, turbine and engine control systems.

However, the programme faced several technical problems. These included the development of high-temperature materials, turbine blades capable of operating under extreme conditions, compressor technology and the required thrust-to-weight ratio. The original Kaveri was designed to produce about 81 kN of thrust but generated around 70 kN in its earlier configuration. It also exceeded the planned weight of 1,100 kg.

The performance gap meant that the engine could not meet the requirements of the Tejas programme. Limited domestic testing infrastructure and restricted access to advanced foreign technology also affected its development. Tejas therefore moved ahead with foreign powerplants.

Kaveri gets a new role

The Kaveri programme was not abandoned after it failed to meet the original fighter-engine requirement. DRDO instead pursued a dry, non-afterburning derivative for other propulsion requirements. The derivative eventually found a role in the planned Ghatak UCAV. The programme has also helped build capabilities in several areas of aircraft-engine development. These include compressors, turbines, combustion systems, high-temperature materials, engine controls and manufacturing.

According to the source material, the programme has produced multiple prototypes and accumulated more than 3,200 hours of testing. It has also developed a qualified Full Authority Digital Engine Control system and certified high-temperature materials for aero-engine applications. Il-76 flight testing has provided Indian engineers with experience of operating an indigenous gas-turbine engine under actual flight conditions.

What the latest trial means

The latest 48.5 kN thrust reading is one part of a much longer Kaveri development programme. The engine now has to go through airworthiness assessment, certification and integration before it can be considered for operational use.

The programme's wider significance lies in the engineering experience built during decades of development. The work has helped India develop capabilities across several critical areas required for indigenous aircraft engines.

The Kaveri began as an effort to power the country's first indigenous fighter aircraft. Its derivative is now being developed for a different role, with the Ghatak UCAV providing a new application for the technology. The latest Russian trials mark another stage in that effort.