An Il-76 flying testbed fitted with India’s Kaveri engine during flight testing in Russia in 2010. (Wikimedia Commons)
India’s indigenous Kaveri Derivative Engine (KDE), also known as the Kaveri dry engine, has reportedly achieved a peak dry thrust of 48.5 kilonewtons (kN) during its latest high-altitude and flight trials in Russia.
The reported result is above the engine’s target of around 46 kN and marks another step in India’s long-running effort to develop an indigenous military aircraft engine. The engine is being developed by the Defence Research and Development Organisation’s (DRDO) Gas Turbine Research Establishment (GTRE) for unmanned aircraft, including the planned Ghatak stealth Unmanned Combat Aerial Vehicle (UCAV).
From Kaveri fighter engine to a dry engine for drones
The Kaveri programme began in 1989, with the original objective of developing an indigenous afterburning turbofan to power India’s Light Combat Aircraft (LCA), now known as Tejas.
The programme produced multiple prototypes and accumulated thousands of hours of testing. According to government records, nine full prototype engines and four core engines were developed, with more than 3,200 hours of engine testing conducted.
The Kaveri also became the first indigenously developed military gas turbine engine in India to undergo flight testing, when it was integrated with an Ilyushin Il-76 flying test bed in Russia.
However, the original engine could not meet the thrust requirement of the Tejas. Government records state that the Kaveri was capable of around 72 kN of thrust, while the LCA required approximately 84 kN. The engine was therefore not integrated into the Tejas, which continues to use an imported engine.
Rather than ending the programme, DRDO moved towards developing derivatives of the Kaveri for applications with lower thrust requirements.
One of the most important outcomes was the Kaveri Derivative Engine, a non-afterburning or “dry” version designed primarily for unmanned aircraft.
Development of the Kaveri Derivative Engine
The KDE programme gained momentum as GTRE modified existing Kaveri engines and tested them for UAV applications.
According to Janes, the derivative engine development programme began in 2019. The initial phase involved converting existing Kaveri engines into technology demonstrators, while a second phase involved the development of new derivative engine prototypes.
The engine subsequently underwent extensive ground testing in India and high-altitude testing in Russia.
At Russia’s Central Institute of Aviation Motors (CIAM), the engine was tested under simulated high-altitude conditions, including conditions equivalent to an altitude of about 13,000 metres. These tests were important because jet engines have to maintain stable operation despite major changes in air pressure and temperature at high altitude.
By 2024, the dry version had received clearance to proceed towards inflight testing. DRDO material put its thrust capability at approximately 49 to 51 kN, while also identifying the engine as suitable for UAV applications such as Ghatak.
In July 2025, the Ministry of Defence said two KDE-related projects had been sanctioned. These included the Flightworthy Kaveri Dry Engine Development project costing ₹472.42 crore and the Technology Demonstration of Kaveri Derivative ‘Dry’ Engine project costing ₹251.17 crore. The government described the KDE as the powerplant for the remotely piloted strike aircraft programme.
What happened in Russia
The latest testing was conducted at two major Russian facilities, CIAM and the Gromov Flight Research Institute.
At CIAM, the engine underwent high-altitude testing designed to reproduce the pressure and temperature conditions experienced during flight at high altitude.
The engine was also evaluated in flight using a modified Ilyushin Il-76 flying test bed. One of the aircraft’s existing engines was replaced with the Kaveri derivative, allowing engineers to evaluate the new powerplant under actual airborne conditions.
The Russian testing programme examined the engine under different ambient pressures, Mach numbers and thrust requirements.
During the latest Russian trials, the KDE reportedly reached 48.5 kN of dry thrust, exceeding the approximately 46 kN target. The 48.5 kN figure has been reported in connection with the latest test campaign, although an official DRDO or Ministry of Defence release independently confirming the exact figure has not yet been published.
The reported 48.5 kN result should therefore be distinguished from earlier high-altitude testing, during which the dry Kaveri had also been reported to demonstrate thrust in a similar range.
What comes next
The Russian trial phase is now reportedly complete, with the engine expected to return to India.
The next major stage is certification and airworthiness evaluation. CEMILAC, the Centre for Military Airworthiness and Certification, is expected to examine the test data and other parameters before the engine can receive the necessary clearance.
The latest result does not mean that the Kaveri derivative has already entered operational service. The engine still has to complete certification and subsequently be integrated and evaluated with its intended aircraft platform.
The reported result moves the engine closer to certification and eventual integration with its intended unmanned aircraft platform.
Why the 48.5 kN milestone matters
The significance of the KDE programme goes beyond the thrust figure itself.
India has spent decades developing expertise in military gas turbine technology. Although the original Kaveri did not become the powerplant for the Tejas, the programme created important capabilities in engine design, materials, testing and control systems.
The government has previously said that the Kaveri programme produced nine full prototype engines and four core engines, while accumulating more than 3,200 hours of testing. It also helped develop technologies that are being used in subsequent engine programmes.
The dry engine represents a different approach. Instead of attempting to meet the much higher thrust requirement of a manned fighter immediately, GTRE has adapted the Kaveri technology for an unmanned combat aircraft where its thrust class is more suitable.
For the Ghatak programme, an indigenous engine could also reduce dependence on foreign propulsion systems for future unmanned combat aircraft.
The government has also taken steps to expand India’s broader aero-engine development ecosystem. In February 2026, Defence Minister Rajnath Singh reviewed GTRE’s indigenous engine programmes and called for faster progress in developing next-generation aero-engine technologies.
The latest 48.5 kN reported result therefore represents a milestone in a development journey that began with the Kaveri fighter engine in 1989 and has now evolved into a propulsion programme for India’s next generation of unmanned aircraft. The next test for the programme will be certification, followed by integration with the Ghatak platform.
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