India’s progress toward self-reliance in military aviation engine technology has been significantly enhanced by the Kaveri Derivative Engine (KDE) and its advanced iteration, Kaveri 2.0 (K9/K10 engines). The Gas Turbine Research Establishment (GTRE) is the driving force behind these initiatives, which are designed to address the deficiencies of the original GTX-35VS Kaveri engine, which failed to meet the propulsion requirements for the Tejas LCA (Light Combat Aircraft). The derivative programs concentrate on specialised applications and next-generation enhancements to support India’s future combat aircraft, even though the initial Kaveri engine only produced 70-75 kN of thrust, which is less than the required 81 kN.
Global Examples of Derivative Engine Development
It is a common practice worldwide to develop derivative engines from original designs that have failed or are underperforming; India is not the only country to do so. Ironically, the GE-F404, which powers the LCA, also has a comparable backstory. In the 1950s, the General Electric J79 was a pioneering afterburning turbojet that powered legendary aircraft such as the F-4 Phantom II. Nevertheless, the initial variants were plagued by reliability issues, such as compressor stalls and restricted service life. GE was compelled to improve the engine’s design, with a particular emphasis on turbine cooling and compressor aerodynamics, in response to these obstacles.
The lessons learned from the development of the J79 were instrumental in developing GE’s next-generation engines. In the late 1970s, GE developed the F404 turbofan for the F/A-18 Hornet, leveraging this experience. Thanks to advancements in digital engine control and enduring materials, the F404 was significantly more reliable, efficient, and compact than the J79.
Kaveri 2.0 incorporates technological advancements that include improved thrust capabilities. It is anticipated to achieve a dry thrust of 55-58 kN and a combined afterburner thrust of 90-100 kN, which is comparable to engines such as the GE F414
The F404’s performance established it as a standard for contemporary fighter engines, and it was ultimately chosen for India’s Tejas LCA (as the F404-IN20 variant). The F404’s core was subsequently expanded by GE to produce the F414, which is currently powering the F/A-18E/F Super Hornet and will be employed in India’s Tejas Mk2. The F414 demonstrated that the iterative development of a troubled engine program resulted in world-class propulsion systems by increasing thrust by 35% while maintaining reliability.
Similarly, the Chinese encountered a similar fate with the WS-10 (Taihang) turbofan, which is now used to power sophisticated fighters such as the J-20 stealth aircraft. The WS-10B and WS-10C are derivatives of the WS-10. The WS-15 engine has been in the works for nearly 3 decades.
Kaveri Derivative Engine (KDE)
Coming back to the topic, the Kaveri Derivative Engine (KDE) is a simplified, non-afterburning version of the original Kaveri engine that has been specifically designed for unmanned aerial systems. The KDE is designed to be optimised for platforms such as the DRDO Ghatak stealth UCAV, which do not require high after-burning thrust and generate an estimated 46 kN of dry thrust. This variant is well-suited for secondary propulsion functions and autonomous drones, as it prioritises fuel efficiency and reliability over raw power. The elimination of the afterburner results in a reduced weight, a modular design that facilitates integration, and lower operational costs. These features are particularly advantageous for long-endurance UAV missions. The KDE is a critical stepping stone in the development of basic turbofan technologies, which are then scaled up to more powerful variants, despite not being specifically designed for manned fighters.
The Kaveri 2.0 engines have a wide range of potential applications. They could be adapted for naval and trainer aircraft, function as interim or backup engines for the AMCA (5th-generation fighter), or replace GE F414 engines in later production batches of the Tejas Mk-II
Kaveri 2.0 Program: K9 and K10 Engines
The Kaveri 2.0 program, which includes the K9 and K10 engines, is designed to solve the constraints of the original Kaveri engine. The K9 engine serves as a prototype and testbed for the validation of new technologies within a restricted flight envelope. In contrast, the K10 engine is intended to be a production-standard model that is developed with foreign collaboration and is designed to provide 90-100 kN of thrust for future aircraft.
Kaveri 2.0 incorporates technological advancements that include improved thrust capabilities. It is anticipated to achieve a dry thrust of 55-58 kN and a combined afterburner thrust of 90-100 kN, which is comparable to engines such as the GE F414. The performance is further improved by making use of advanced materials, including titanium alloys (Ti6246) for lightweight components and nickel-based superalloys for high-temperature portions such as turbine blades.
Furthermore, the Full Authority Digital Engine Control (FADEC) system enhances responsiveness, fuel efficiency, and reliability, while single-crystal blades enhance thermal efficiency and durability. The flat-rated design is a critical feature for India’s diverse operational environments, as it guarantees consistent performance in the face of varying altitudes and temperatures.
The Kaveri 2.0 program’s success would represent a significant stride toward self-reliance, as it would considerably reduce India’s reliance on foreign engines, particularly for the AMCA and future UAVs, despite these obstacles.
Applications and Challenges
The Kaveri 2.0 engines have a wide range of potential applications. They could be adapted for naval and trainer aircraft, function as interim or backup engines for the AMCA (5th-generation fighter), or replace GE F414 engines in later production batches of the Tejas Mk-II. Nevertheless, the program is confronted with a number of obstacles, such as the necessity of consistently achieving a thrust of 90+ kN, which necessitates additional aerodynamic and metallurgical refinements.
Additionally, GTRE is seeking $1 billion for Kaveri 2.0 and has formed a partnership with Safran of France to enhance its core. Funding and collaboration are also essential. Given previous delays, the timeline for complete operational clearance may be extended to 2030. The Kaveri 2.0 program’s success would represent a significant stride toward self-reliance, as it would considerably reduce India’s reliance on foreign engines, particularly for the AMCA and future UAVs, despite these obstacles.
Strategic Importance
In summary, India’s strategic initiative to develop indigenous aircraft engine capabilities is symbolised by the Kaveri Derivative Engine (KDE) and Kaveri 2.0 (K9/K10). The Kaveri 2.0 is designed to provide power to next-generation fighters, thereby bridging the gap until a completely mature high-thrust engine is developed, while the KDE supports unmanned systems. India is on the brink of becoming a significant participant in the military propulsion sector, a development that is consistent with its Aatmanirbhar Bharat (Self-Reliant India) vision, as a result of ongoing investment and international collaboration. Not only will the success of these programs improve India’s defence capabilities, but it will also firmly establish its position in the global aerospace industry.
The writer is the Publisher of Frontier India and the author of the book Foxtrot to Arihant: The Story of Indian Navy’s Submarine Arm.
