SOURCE: AFI
India’s pursuit of self-reliance in aerospace technology has taken a significant step forward with the development of the Kaveri Derivative Engine (KDE) for the Ghatak stealth Unmanned Combat Aerial Vehicle (UCAV). A notable feature of this engine is its 75% commonality with the Kaveri Afterburner engine, a design choice that promises to streamline development, reduce costs, and accelerate India’s indigenous defense capabilities. This advancement, spearheaded by the Gas Turbine Research Establishment (GTRE) under the Defence Research and Development Organisation (DRDO), underscores a strategic evolution of the long-standing Kaveri engine program.
The KDE is a non-afterburning (dry) variant of the Kaveri engine, specifically engineered to power the Ghatak UCAV—a 13-tonne stealth platform designed for deep-strike missions in contested airspace. With a dry thrust output of approximately 49-51 kN, the KDE meets the power requirements of this unmanned system, where endurance and infrared signature reduction take precedence over the raw thrust needed for manned fighters. The Ghatak, envisioned as a complement to India’s fifth-generation Advanced Medium Combat Aircraft (AMCA), represents a critical component of the Indian Air Force’s (IAF) future unmanned strike capabilities.
The decision to base the KDE on the Kaveri Afterburner engine, which achieves 73-75 kN of thrust with its afterburner engaged, leverages decades of research and refinement. This 75% commonality—encompassing core components like the compressor, combustor, and turbine—ensures that the KDE benefits from the Kaveri’s established design while being optimized for the Ghatak’s unique mission profile. By reusing proven subsystems, GTRE aims to minimize development risks, reduce production timelines, and lower lifecycle costs, aligning with India’s broader “Make in India” initiative.
Recent milestones have revitalized the program. In 2023, the Kaveri underwent high-altitude testing in Russia, achieving a stable dry thrust of 48.5 kN. By November 2024, BrahMos Aerospace successfully developed a 29 kN afterburner section, boosting the Kaveri’s total thrust to 79 kN. On December 23, 2024, GTRE announced that the dry Kaveri variant had been cleared for inflight testing aboard a modified Ilyushin Il-76 testbed in Russia, with trials set to begin in February 2025. These tests, spanning 70 hours, will validate the engine’s performance under real-world flight conditions, a critical step toward its integration into the Ghatak.
The 75% commonality between the KDE and the Kaveri Afterburner engine offers multiple strategic benefits. First, it capitalizes on the extensive testing and upgrades already conducted on the Kaveri platform, including its flat-rated design that maintains thrust in humid or dry conditions—a vital feature for India’s diverse climate. Second, shared components simplify logistics, maintenance, and supply chains, enhancing operational efficiency for the IAF and potentially the Indian Navy, which has explored Kaveri derivatives like the Kaveri Marine Gas Turbine (KMGT).
This approach also paves the way for future scalability. GTRE is actively pursuing the Kaveri 2.0, an enhanced variant targeting 90-95 kN of thrust with an afterburner, which could eventually power manned fighters like the Tejas Mk1A or Mk2. The KDE’s development provides valuable data and experience, serving as a stepping stone toward this more ambitious goal. By maintaining significant overlap with the Kaveri Afterburner engine, GTRE ensures that advancements in one program can inform the other, fostering a cohesive ecosystem of indigenous engine technology.
Despite its promise, the KDE faces challenges. Weight remains a concern, with the dry Kaveri variant currently at approximately 900-1,000 kg—acceptable for unmanned platforms like Ghatak but heavier than ideal for manned fighters. GTRE is exploring lighter alloys and composites to reduce this figure, a process that will intensify if the Kaveri 2.0 is greenlit for fighter applications. Additionally, the upcoming inflight trials in Russia will be a litmus test for the engine’s reliability, endurance, and integration with aircraft systems, particularly under the high-altitude and dynamic conditions the Ghatak will encounter.
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