Kaveri Engine & Tejas: Powering India’s Indigenous Aerospace

The Kaveri engine project, initiated by the Gas Turbine Research Establishment (GTRE) of the Defence Research and Development Organisation (DRDO) in the 1980s, was intended to power the indigenous Light Combat Aircraft (LCA) Tejas. However, the project faced numerous challenges, leading to its failure to meet the requirements for the Tejas.

Here are the key reasons for its delay:

Technological Challenges

• Thrust Deficiency:  The Kaveri engine was unable to achieve the required thrust levels for the Tejas. Initially designed to generate 81 kN of thrust with afterburner, it could only achieve around 70-75 kN, which was insufficient for the LCA’s operational needs.  Weight Issues the Kaveri engine ended up being heavier than initially planned, which negatively impacted the overall performance and weight-to-thrust ratio of the Tejas aircraft.  The Kaveri derivative engine along with the afterburner section added weighs around 1180kg which has come down from 1235kg which has come down from older prototypes that weigh over 1400kg.  The ideal weight of the Kaveri Derivative engine should be within 1000 Kg and work is underway to improve the materials used and reduce over engineered components over the next few years.
• Reliability and Durability: The engine faced significant issues in reliability and durability, particularly in high-altitude, high-temperature environments. Critical components, like the turbine blades, could not withstand the extreme conditions during long-duration tests.

Materials and Manufacturing

• Advanced Materials: The development of high-temperature materials, especially single-crystal turbine blades, was a major hurdle. India lacked the advanced materials technology and the capability to manufacture these components with the required precision.
• Manufacturing Expertise: The precision manufacturing required for the complex components of a jet engine was not fully developed in India at the time. This led to inconsistencies and quality issues in the production of critical engine parts.

Testing and Validation Issues

• Lack of Testing Infrastructure: India did not have the complete infrastructure required for comprehensive engine testing, such as high-altitude test facilities. This led to delays and incomplete validation of the engine’s performance under operational conditions.
• Limited Iterative Testing: Engine development requires repeated prototyping and testing cycles. Due to budgetary constraints and lack of experience, GTRE could not conduct as many iterative tests and refinements as needed, which slowed down the development process.

Project Management and Delays

• Overambitious Goals: The Kaveri project set ambitious goals given India’s then-existing technological and industrial base. The timeline was overly optimistic, and initial estimates did not fully account for the complexity of developing a jet engine from scratch.
• Frequent Design Changes: The design specifications for the Tejas aircraft evolved over time, leading to frequent changes in the engine requirements. This necessitated continuous modifications in the Kaveri engine’s design, further delaying the project.

International Sanctions and Technology Denials

• Post-Pokhran Sanctions: After India’s nuclear tests in 1998, international sanctions were imposed, which restricted access to crucial technologies and materials. This significantly impacted the Kaveri engine development, as key technologies from Western countries were no longer available.
• Limited International Collaboration: Attempts to collaborate with foreign entities for technology transfer were limited due to concerns over intellectual property and security. This restricted India’s ability to acquire critical know-how that could have accelerated the engine’s development.

Funding and Resource Constraints

• Inconsistent Funding:  The Kaveri project suffered from inconsistent funding over its lifecycle. Delays and cost overruns further strained the budget, leading to compromises in research and development activities.
• Human Resources:  There was a shortage of specialized human resources with experience in jet engine development. The project faced challenges in attracting and retaining top engineering talent, which is crucial for such a complex endeavor.

Positive Developments on the Kaveri Engine.  Based on unconfirmed sources, there’s encouraging news regarding the Kaveri engine but seems it’s a misleading information.

Safran Audit Clears Kaveri Engine for Aircraft Integration

• According to DRDO’s 2017 Annual Report, five Kaveri engine prototypes—K5, K6, K7, K8, and K9—were tested for approximately 145 hours throughout the year. During these tests, several critical evaluations, including a successful transient test from idle to maximum reheat conditions, were conducted for the first time.
• Most engine tests were performed under installed conditions, accounting for power off-take, customer bleed, and inlet distortion. Following these tests, French aerospace and defense company Safran S.A. conducted a technical audit of the Kaveri engine development.
• The audit report indicated that the Kaveri engine has reached a sufficient level of maturity to proceed with a limited envelope flight test integrated with an aircraft.
• The Kaveri engine program, despite its initial setbacks, continues to be an important part of India’s quest for self-reliance in aero engine technology. The plan for a future Kaveri engine, sometimes referred to as “Kaveri 2.0,” aims to build on the lessons learned from the original Kaveri project while incorporating new technologies and international collaboration.

Also Read, In Depth Analysis: Tejas MK2 or MWF

Here are the key aspects of the plan for the future Kaveri engine, particularly in the context of powering the Tejas Mk II:

International Collaboration

• Safran Collaboration: India has engaged in discussions with the French company Safran, which produces the M88 engine used in the Rafale fighter jets. Safran is expected to assist in reviving the Kaveri engine by providing technology transfer and expertise, especially in areas like single-crystal turbine blades, low-bypass ratios, and high-temperature materials. The goal is to enhance the Kaveri engine’s thrust and reliability to meet the requirements of future Indian aircraft.
• Joint Development: The collaboration with Safran might involve joint development of a new or improved version of the Kaveri engine, with a focus on achieving the required thrust of over 98 kN (with afterburner) for the Tejas Mk II and potentially the Advanced Medium Combat Aircraft (AMCA).

Technological Upgrades

• Thrust Enhancement: One of the main objectives for Kaveri 2.0 is to address the thrust deficiency. The plan is to increase the thrust output to at least 98-100 kN, which is necessary for the Tejas Mk II’s operational performance. This would involve redesigning key components and integrating advanced materials that can handle higher temperatures and stress.
• Weight Reduction:  Efforts are being made to reduce the engine’s weight without compromising its structural integrity. This could be achieved through the use of lighter materials and optimized design.
• Advanced Control Systems:  Modernizing the engine control systems with Full Authority Digital Engine Control (FADEC) is also part of the upgrade. This will improve the engine’s efficiency, reliability, and response time during various flight conditions.

Testing and Validation

• Comprehensive Testing Infrastructure: To overcome the previous limitations, there is a plan to establish or upgrade existing testing facilities in India. This includes high-altitude and high-temperature testing environments, as well as endurance testing to validate the engine’s long-term performance.
• Iterative Development: The new approach involves a more iterative and modular development process, allowing for incremental improvements and quicker validation cycles. This should help identify and fix issues earlier in the development phase.

Application to Tejas Mk II and Beyond

• Tejas Mk II: While the initial Tejas Mk II aircraft will likely use the General Electric F414 engine, the plan is to eventually replace this with an indigenous engine, potentially the Kaveri 2.0, if it meets the required performance criteria. The goal is to achieve a fully indigenous fighter jet, reducing dependency on foreign engines.
• Advanced Medium Combat Aircraft (AMCA):  The future Kaveri engine could also power the AMCA, India’s next-generation stealth fighter. This would require further enhancements to meet the thrust and stealth requirements of a fifth-generation aircraft.

 Long-term Strategy

• Self-Reliance in Aero Engines:  The Kaveri 2.0 is part of a broader strategy to achieve self-reliance in critical technologies. Success in this program could lead to the development of a family of indigenous engines for various aircraft, including drones, trainers, and transport planes.
• Strategic Partnerships:  Alongside international collaboration, there is also an emphasis on building domestic capabilities. This includes developing a robust supply chain for high-performance materials and components, fostering research and development, and nurturing talent within India’s aerospace sector.

Speaking to Mr. Thaariq Ahmad, COO of NextLeap Aeronautics Pvt Ltd, Bangalore, said India’s efforts to develop indigenous aero engines, particularly for military aircraft, face several challenges and “grey areas.” These issues are multifaceted, encompassing technical, industrial, and strategic dimensions. Here are some of the key areas:

Technological Complexity Materials Science:

• Developing high-performance materials, especially for turbine blades that can withstand extreme temperatures and stress, is a significant challenge. India lacks the advanced materials technology required for efficient and durable engine components.
• High Precision Manufacturing: Aero engines require extremely tight tolerances and precision manufacturing, which are areas where India’s industrial base needs further development.
• Design Expertise: Designing a modern jet engine is an intricate process requiring deep expertise in aerodynamics, thermodynamics, fluid mechanics, and other fields. India is still building the necessary ecosystem of experienced engineers and scientists.
• Testing and Validation Infrastructure: India has limited infrastructure for testing and validating jet engines, particularly in areas like high-altitude and high-temperature performance. Building this infrastructure is capital-intensive and time-consuming.
• Iterative Development: Engine development requires extensive prototyping and testing. India’s limited experience in aero engines means that the iterative process of refining designs through multiple versions is slower compared to more established nations.
• Dependency on Foreign Technology Component and Technology Imports: India still relies on foreign technology and components for several critical aspects of engine development. This dependence hinders full indigenous capability and poses risks due to technology denials or restrictions.
• Licensing and Collaboration Limitations: Even when collaborating with foreign companies, there are restrictions on sharing certain technologies, which slows down India’s ability to absorb and indigenize advanced know-how.
• Strategic and Policy Challenges Long Development Cycles: Aero engine development is a long-term endeavor, often taking decades. Political and bureaucratic hurdles, coupled with inconsistent funding and shifting priorities, have hampered continuous progress.
• IPR and Knowledge Transfer: Intellectual Property Rights (IPR) issues and the reluctance of foreign partners to transfer cutting-edge technology remain significant barriers. Safeguarding sensitive technology while achieving self-reliance is a delicate balance.
• Economic Constraints High R&D Costs: Aero engine development is highly capital-intensive. The Indian defense budget, although substantial, has many competing demands, which often leads to funding constraints for long-term R&D projects.
• Cost Overruns and Delays: Past programs, such as the Kaveri engine, have seen significant cost overruns and delays. These setbacks undermine confidence in domestic capabilities and can lead to reliance on foreign engines as stop-gap solutions.
• Human Resource Development Talent Pool: While India has a growing pool of engineers, there is still a shortage of specialized expertise in fields critical to aero engine design and manufacturing. Bridging this talent gap is crucial for future programs.
• Knowledge Retention: High attrition rates in state-run organizations and limited opportunities for hands-on experience also pose challenges to maintaining and expanding expertise.

The challenges and gaps in India’s aero engine development efforts underscore the need for a comprehensive approach. This should include sustained R&D investment, strategic international collaborations, capacity building, and a long-term vision that aligns with national security and industrial policy goals. Overcoming these challenges is crucial for India to achieve self-reliance in aero engine technology and reduce its dependence on foreign suppliers.

Recent reports, though dated to around 2018, mention an audit by Safran that cleared five Kaveri engine prototypes (K5-K9) after 145 hours of testing. The engine is now poised for integration with a limited serial production Tejas aircraft for testing. This development, shaped by international collaboration, technological upgrades, and strategic planning, marks a significant step forward.

The Kaveri engine has reached a stage of limited testing integration with an aircraft, without further involvement from French business unit at this point. If successful, this initiative could provide India with a domestically produced engine for the Tejas Mk II and future platforms, greatly enhancing the country’s aerospace capabilities and reducing its reliance on foreign suppliers. However, achieving this will require sustained commitment, resources, and effective management to overcome the historical challenges faced by the program.