Indigenous 350kg turbojet engine a milestone for private defence tech

India achieves a major aerospace milestone with its first indigenous 350kg thrust-class turbojet engine, strengthening domestic defence manufacturing capabilities

More than four decades after India embarked on its ambitious quest to build an indigenous fighter aircraft engine, the successful development and delivery of the country’s first indigenous 350kg thrust-class expendable turbojet engine has emerged as an important technological milestone. 

Designed and developed by Bengaluru-based Gas Turbine Research Establishment (GTRE) — a premier laboratory of Defence Research and Development Organisation (DRDO) — the first indigenous expendable turbojet engine has been manufactured and delivered by Hyderabad-based Azad Engineering. 

Built as an expendable, short-duration turbojet engine for single-mission applications, it can power tactical cruise missiles, anti-ship missiles, and long-range loitering munitions. The indigenous technology will reduce foreign dependency for critical aerospace propulsion systems. Although the newly developed engine is not intended to power fighter aircraft, defence experts believe it represents a critical step in mastering the complex technology of gas turbine engines. Regarded as one of the most difficult frontiers in aerospace engineering, engine technology has kept India dependent on foreign suppliers despite significant advances in aircraft design. 

Unlike previous indigenous propulsion efforts, which remained largely confined to laboratories and public-sector manufacturing units, the new engine has been built by Azad Engineering, a company better known globally for manufacturing precision rotating components for aerospace giants such as GE Aerospace, Honeywell, Rolls-Royce, Mitsubishi Heavy Industries, and Siemens Energy. Defence analysts said this transition from manufacturing turbine blades and precision components to producing an entire indigenous engine marks an important evolution of India’s private defence industry. 

“The collaboration is now visible and this is far more than the delivery of a 350-kg engine. It demonstrates that Indian industry is now capable of manufacturing complete propulsion systems to aerospace-grade standards. The focus should now be on developing indigenous aero-engine technologies to deliver 110-kN or 120-kN engines,” said Air Vice Marshal Anil Golani (retd), former Director General of Centre for Aerospace Power and Strategic Studies. 

“If India is to build indigenous fighter engines in the future, it will have to provide the much-needed platform and funding resources like the satellites and other space programmes such as Mission Gaganyaan and Chandrayaan with fixed accountability to deliver within a certain time frame,” he told Business Standard. GTRE has spearheaded India’s aero-engine research, beginning with the ambitious Kaveri engine programme in the 1980s. Conceived to power the Light Combat Aircraft (LCA), later christened Tejas, the Kaveri turbofan was expected to place India among the select group of countries capable of designing indigenous fighter engines. 

Despite years of research, however, the programme struggled to achieve the required thrust, weight and reliability needed for frontline fighter operations. 

The challenge becomes even greater with India’s Advanced Medium Combat Aircraft (AMCA), which will require a new 120 kN-class engine, far more sophisticated than anything India has produced so far. Recognising this gap, the government has, however, launched the Advanced High Thrust Engine (AHTE) programme while simultaneously pursuing co-development with France’s Safran. 

Unlike earlier technology-transfer arrangements, Indian negotiators are seeking genuine design know-how in critical technologies such as single-crystal turbine blades, high-temperature materials and thermal barrier coatings - the important technologies that prevented Kaveri from achieving operational success. 

Defence scientists argued that the Kaveri programme was not a complete failure. “It built an indigenous knowledge base, created specialised testing facilities and trained a generation of Indian engineers in complex aero-engine technologies,” said N K Samal, a retired air force officer. 

Years after GTRE began drawing the first blueprints of the Kaveri engine, those blueprints are finally finding expression in precision-manufactured blades, combustors, and turbine assemblies built by Indian private industry. “The engine delivered last week may not power a fighter aircraft, but it has strengthened the industrial foundation upon which India’s future fighter engines will eventually be built,” Samal said.

 

According to the Ministry of Defence (MoD), the landmark achievement by GTRE and Azad Engineering for India’s aerospace and defence ecosystem marks the culmination of years of precision engineering, advanced manufacturing and close partnership between the scientific and industrial communities. 

“Mastered by only a handful of nations, jet engine technology is widely regarded as one of the most sophisticated engineering disciplines in the world. Delivery of such a complex system based on the design of DRDO demonstrates the growing technological capabilities of the Indian defence industry,” the MoD said in a statement. 

Defence Secretary and Secretary, Department of Defence R&D and Chairman of DRDO Rajesh Kumar Singh has complimented the partnership of GTRE and the industry. “The private industry has been instrumental in transforming the vision into a historic milestone,” he said.