Kaveri (GTRE GTX-35VS) is an indigenous turbofan aero-engine programme run by the Gas Turbine Research Establishment (GTRE), a DRDO laboratory based in Bengaluru. Originally sanctioned in 1989 to power the HAL Tejas Light Combat Aircraft, the engine failed to meet its original weight and thrust targets on schedule and was formally delinked from the Tejas programme in 2008. Rather than being shelved, the Kaveri effort has since been repurposed into a dry (non-afterburning) derivative for India’s Ghatak stealth unmanned combat aerial vehicle (UCAV), and — under a 2025-26 “Kaveri 2.0” revival — into the technology base for a future fighter-class afterburning engine.[1][2]
The Kaveri programme was sanctioned in 1986–1989 with the goal of giving India an indigenous afterburning turbofan in the 80+ kN thrust class to power the Tejas, ending reliance on the American GE F404 engine that ultimately equips Tejas Mk1. Development proved far harder than anticipated: repeated shortfalls in thrust-to-weight ratio, high-altitude relight reliability, and metallurgical/single-crystal blade technology meant the engine never achieved the performance or airworthiness certification needed for a fighter application. After roughly two decades and nine prototype engines, the Ministry of Defence formally delinked Kaveri from the Tejas programme in 2008, and the LCA continued with the F404 (Mk1) and later the more powerful F414 (Mk1A/Mk2).[3]
In 2018, an evaluation by French engine maker Safran assessed the Kaveri core as having reached a maturity level suitable for further aircraft-integration work, and a Kaveri-Safran collaboration was explored to help resolve the engine’s persistent hot-section and afterburner shortfalls — although a full joint-development deal was never finalised on the scale originally envisaged.[2]
Rather than continuing to chase a fighter-grade afterburning engine on the original timeline, GTRE repurposed the Kaveri core into the Kaveri Derivative Engine (KDE), also referred to as the “Dry Kaveri” — a non-afterburning turbofan stripped of the reheat/afterburner fuel system and fitted with a simplified nozzle, tuned via FADEC (Full Authority Digital Engine Control) for efficient sustained subsonic cruise rather than supersonic dash. This dry configuration removes the weight and complexity that had proved hardest to solve, while still leveraging the compressor, combustor and turbine technology matured over three decades of Kaveri development.[1][4]
The KDE is sized to power the DRDO Ghatak stealth flying-wing UCAV, which requires roughly 46 kN of thrust; testing has shown the dry engine delivering approximately 49–52 kN, comfortably exceeding that benchmark. Godrej & Boyce has been contracted to manufacture production-standard Dry Kaveri engines, with the first unit (designated D1) handed over in September 2025 for baseline validation.[5][1]
By mid-2025 the programme had logged more than 140 cumulative test hours — around 70 hours of ground running at GTRE’s Bengaluru test facility and roughly 75 hours of altitude/flight-representative testing conducted in Russia (India has used Russian high-altitude test facilities for engine certification work in the past, given the lack of a comparable domestic altitude test chamber for large turbofans). Indian defence media reported in March 2026 that the Kaveri dry engine was nearing certification, positioning it to power early Ghatak flight-test articles.[6][1]
In parallel, DRDO/GTRE restarted work on a full afterburning Kaveri variant aimed at the fighter-engine thrust class, informally dubbed “Kaveri 2.0.” On 16 February 2026, Defence Minister Rajnath Singh witnessed a full-afterburner test of the Kaveri engine at GTRE Bengaluru — described by officials as a milestone in mastering complex afterburner/reheat technology that had defeated earlier iterations of the programme. The current afterburning-variant goal is thrust in the 80–85 kN class, sufficient to be considered for a future Tejas Mk1A/Mk2-class fighter re-engining or for contributing core-engine technology to India’s Advanced Medium Combat Aircraft (AMCA) programme.[7][8]
Kaveri 2.0 is explicitly framed as a long-horizon programme: officials and analysts place operational readiness for a genuinely fighter-capable derivative in the mid-to-late 2030s. In the interim, the AMCA programme’s initial squadrons are expected to rely on an imported or co-developed engine (from General Electric or a European partner such as Safran/Rolls-Royce) rather than wait for an evolved Kaveri core.[2][1]
Kaveri is a twin-spool, axial-flow turbofan featuring a three-stage low-pressure compressor and six-stage high-pressure compressor, an annular combustor, single-stage high-pressure turbine and single-stage low-pressure turbine, driven through a bypass-ratio design intended to balance fuel efficiency with the thrust density needed for combat manoeuvring. Persistent technical hurdles across the programme’s history included single-crystal turbine blade metallurgy, high-temperature-tolerant materials for the combustor and afterburner liner, and full-authority digital engine control (FADEC) software maturity — areas where India has progressively built indigenous capability through the 1990s-2020s, aided in part by the Safran technical assessment and by domestic metallurgy programmes at DRDO’s other materials laboratories.[3][4]
Even though Kaveri did not deliver its originally intended fighter-engine outcome on schedule, the programme is widely regarded within India’s defence-industrial establishment as having built essential indigenous capability in aero-gas-turbine design, testing and certification — skills with no substitute and historically monopolised by a handful of countries (the US, Russia, UK/France, and more recently China). The pivot to a dry UCAV engine gives GTRE a near-term production application to sustain the industrial base and generate revenue and flight-hours data, while Kaveri 2.0 keeps the door open for an eventual indigenous fighter-engine capability that reduces dependence on imported GE and Safran/Snecma powerplants across the Tejas and AMCA programmes.[2][6]
| Type | Twin-spool axial-flow turbofan (afterburning, original design intent) / non-afterburning derivative (KDE / “Dry Kaveri”) |
| Developer | Gas Turbine Research Establishment (GTRE), DRDO |
| Manufacturing partner | Godrej & Boyce (production of Dry Kaveri units) |
| Programme sanctioned | 1986–1989 |
| Delinked from Tejas | 2008 |
| Dry thrust (KDE / Dry Kaveri) | ~49–52 kN |
| Target afterburning thrust (Kaveri 2.0) | ~80–85 kN class |
| Cumulative test hours (as of mid-2025) | 140+ hours (≈70 hrs ground testing in Bengaluru, ≈75 hrs altitude testing in Russia) |
| Primary near-term application | DRDO Ghatak stealth UCAV (dry variant) |
| Long-term application (aspirational) | Future Tejas re-engining / AMCA-class fighter engine (Kaveri 2.0) |
| Status (mid-2026) | Dry variant nearing certification for Ghatak; afterburning Kaveri 2.0 in early test/revival phase following Feb 2026 full-afterburner ground test |