The first indigenous Expendable Turbo Jet Engine in the 350 kg thrust class has been developed by DRDO's Gas Turbine Research Establishment and built by its industry partner, Azad Engineering of Hyderabad. The engine was realised and delivered to GTRE on 22 July. The Ministry of Defence announced it on Thursday evening.

GTRE holds the design. Azad Engineering did the manufacturing and the assembly.

That split is the point of the announcement. A DRDO laboratory drawing an engine and a private firm turning it into running hardware is a working arrangement rather than a memorandum of understanding, and the Ministry described the delivery as the culmination of years of precision engineering, advanced manufacturing and close work between India's scientific and industrial communities. Anyone who has followed Indian propulsion for any length of time knows why a delivered engine is treated as news at all. The distance between an engine on paper and an engine in metal has been the country's most stubborn defence technology problem.

Expendable Turbo Jet Engine handed over by Azad Engineering

Dr K Rajalakshmi Menon, Distinguished Scientist and Director General (Aeronautical Systems), and Dr SV Ramanamurty, Outstanding Scientist and Director of GTRE, received the engine. Shri Rakesh Chopdar, Chief Executive Officer of Azad Engineering, handed it over.

Defence Secretary Shri Rajesh Kumar Singh, who holds additional charge as Secretary, Department of Defence R&D and Chairman DRDO, complimented the GTRE and industry partnership behind it.

The Ministry called jet engine technology one of the most demanding engineering disciplines in the world, mastered by only a handful of nations, and said delivery of a system this complex against a DRDO design shows how far Indian defence manufacturing has come.

Ministry of Defence post on X: 


What expendable means in a jet engine

An expendable turbojet is designed to run once. It is not overhauled, not stripped and rebuilt, not returned to a depot. Everything a conventional aero engine spends weight, cost and metallurgy on for the sake of a long service life can be traded away, and the design priorities move instead to unit cost, part count and the ability to make the thing in numbers.

That is a different engineering problem from the one GTRE has wrestled with on manned fighter propulsion. It is not an easier one. Rotating components still turn at high speed and high temperature, tolerances are still unforgiving, and a single use engine that fails on its single use has failed completely.

No application named, and none expected

The statement gives the thrust class, the design agency, the manufacturing partner and the date of delivery. It names no platform, no programme and no user service. End use is rarely announced when a first engine is handed over.

Engines in this bracket are the standard propulsion for subsonic cruise missiles, target drones and long endurance loitering munitions. GTRE's small turbofan, Manik, powers the Indigenous Technology Cruise Missile and the Long Range Land Attack Cruise Missile, the second of which flew again on 15 June from Dr APJ Abdul Kalam Island. Whether the new turbojet is meant for anything in that family is not stated, and IDW is not treating it as stated.

The engine India has not built yet

India still buys the engines that matter most to it. Twenty two Tejas Mk1A airframes stood completed and undeliverable this year for want of F404 engines from GE Aerospace, and HAL's position at Farnborough was that the supply problem had been worked through rather than designed out.

A 350 kg thrust expendable engine is a smaller object built to a narrower brief, and it does not close that gap. GTRE, whose charter covers the design and development of gas turbine engines for military applications, has worked the small engine end for years alongside the Kaveri, sanctioned in 1989 and never fitted to a production fighter. The small end is where the deliveries are coming from.

Azad Engineering and the private manufacturing route

Azad Engineering is a Hyderabad precision manufacturer whose business is built on complex rotating parts for aero engines and energy turbines, supplied to global original equipment manufacturers. Blades, vanes and the hot end components that are hardest to hold to tolerance are its stock in trade.

DRDO has been steering more of this work outward. The AEW&C Mk II programme this week placed mission systems development with a private partner. Laboratory keeps design authority. Industry takes the build.

GTRE identified Azad Engineering as its partner for the manufacture and assembly of the Expendable Turbo Jet Engine. The firm delivered it on 22 July.