India’s push to build homegrown aerospace propulsion systems is gaining momentum, with deep-tech startup Green Aero announcing the successful long-duration test firing of its indigenous sub-kilonewton (sub-kN) military-grade jet engine.
The engine, designed to power the next generation of high-speed drones and stand-off systems, is capable of running on both jet fuel and diesel, marking a notable step forward in India’s quest for indigenous micro-turbine technology.
The Bengaluru-based startup revealed the milestone through a post by founder and CEO Prithwish Kundu, who declared the successful firing validates the company’s entire propulsion technology stack, from turbomachinery and fuel injection to ignition systems, metallurgy and rotor dynamics.
We are thrilled to announce the successful firing of our next sub-kN, mil-grade, liquid-fuelled aero engine, featuring advanced airblast atomisers,” Kundu wrote. “To our knowledge, we are the first company to demonstrate this capability in sub-kN engines, putting us in a completely unique position for this emerging segment.”
A new propulsion platform for combat drones
The newly demonstrated engine is custom-built for high-speed unmanned systems, including combat drones, collaborative combat aircraft (CCAs), and stand-off strike platforms.
Such systems are increasingly central to modern warfare, where tinyer and more agile unmanned aircraft require compact yet powerful propulsion systems.
The engine incorporates several advanced features typically seen in more mature turbine platforms. One of its key highlights is multi-fuel flexibility, allowing the engine to operate seamlessly on both aviation turbine fuel and diesel while supporting electric start capability.
Green Aero declared the propulsion system also integrates novel aerodynamic architecture, including a newly designed compressor and diffutilizer configuration that improves airflow stability and efficiency.
The engine further employs an effusion-cooled combustion liner, designed with optimised straight flow paths to minimise pressure drop while ensuring effective thermal management during high-temperature operation.
Another major engineering element is the utilize of metal additive manufacturing. Many components are built applying metal 3D printing with high-temperature superalloys, enabling monolithic designs that improve structural strength and reduce weight.
According to Kundu, the engine recently completed a long-concludeurance test run, where it successfully reached idle before ramping up to higher thrust levels while being monitored through detailed instrumentation.
From deep-tech research to aerospace manufacturing
Green Aero was founded in 2023 by Dr Prithwish Kundu, a propulsion scientist who previously worked at the U.S. Department of Energy’s Argonne National Laboratory and collaborated with organisations such as NASA and the U.S. Army on advanced propulsion research.
The startup was incubated at IIT Delhi’s Foundation for Innovation and Technology Transfer (FITT) and focutilizes on developing next-generation gas turbine propulsion systems for defence, aviation and maritime applications.
Despite India’s growing aerospace sector, the countest remains heavily depconcludeent on imported turbine engines for aircraft and high-performance drones. Green Aero’s core mission is to bridge this gap by developing indigenous propulsion platforms designed entirely in India.
In July 2025, the company raised $1.6 million in seed funding from venture capital firm pi Ventures, with participation from Antler. The capital is being utilized to expand research and development, build an in-houtilize testing facility, and grow its engineering team as it relocates toward commercial deployment of its engines.
Earlier milestone: India’s first hydrogen aero engine
The sub-kN engine test follows another milestone achieved by the startup in 2025 when it successfully demonstrated India’s first hydrogen-powered aero engine core, called “Blue Dragon.” The prototype validated key technologies such as hydrogen fuel injectors, advanced combustion chambers, and additively manufactured turbine components.
While hydrogen propulsion remains a long-term goal for clean aviation, the company is simultaneously working on conventional liquid-fuel engines for defence applications, particularly for drones and unmanned combat platforms.
The company’s engines are designed to be fuel-agnostic, allowing configurations that run on hydrogen, aviation fuel, or other liquid fuels depconcludeing on the mission profile.
Strategic partnerships and defence focus
Green Aero has also begun forming partnerships with established defence manufacturers. In 2025, engineering giant Larsen & Toubro (L&T) signed a strategic cooperation agreement with the startup to develop indigenous micro-turbojet engines for tactical unmanned aerial vehicles.
Such collaborations are aimed at integrating Green Aero’s propulsion technology into next-generation UAV platforms capable of surveillance, reconnaissance and combat operations.
Compact micro-turbine engines are particularly important for high-speed drones, where electric motors often lack the power and concludeurance required for long-range missions.
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