As per unconfirmed reports, DRDO's Solid Fuel Ducted Ramjet Technology (SFDR) for air launched tactical missiles tested this year, test not reported.

The state-of-the-art air-to-air missile powered with ‘SFDR’ propulsion enables the missile to intercept aerial threats at very long range at supersonic speeds and is configured with nozzle-less booster, thrust modulation system and sustainer to deliver specific impulse in ramjet mode. The missile was flight tested this year.

Earlier, the Defence Research and Development Organisation (DRDO) successfully tested the Solid Fuel Ducted Ramjet (SFDR) booster on April 8, 2022. The test took place at the Integrated Test Range (ITR).

The SFDR-based propulsion allows the missile to intercept aerial threats at long range and supersonic speeds. The successful test is expected to help the DRDO extend the range of air-to-air missiles. 

Solid-fuel ramjets convert the thermal energy of combustion products into forward thrust without using any moving parts. They typically use an air intake system to compress the incoming air.

The SFDR has been developed by Defence Research and Development Laboratory, Hyderabad in collaboration with other DRDO laboratories such as Research Centre Imarat, Hyderabad and High Energy Materials Research Laboratory, Pune.

SFDR technology is a missile propulsion system based on the concept of Ramjet Engine principle. Here are some key features and technologies involved:

A ramjet is a form of air-breathing jet engine that uses the vehicle’s forward motion to compress incoming air for combustion without a rotating compressor.

In a ramjet, the high pressure is produced by "ramming" external air into the combustor using the forward speed of the vehicle. The external air that is brought into the propulsion system becomes the working fluid.

Ramjets produce thrust only when the vehicle is already moving, ramjets cannot produce thrust when the engine is stationary or static. 

The system utilises a solid fuelled air-breathing ramjet engine.

Unlike solid-propellant rockets, the Ramjet takes up oxygen from the atmosphere during flight. Thus, it is light in weight and can carry more fuel.

It enables the missile to intercept aerial threats at very long range at supersonic speeds.

At present, such technology is available only with a handful of countries in the world.

Air-to-air missiles which use SFDR technology can achieve longer ranges as they do not require oxidisers (take oxygen from the atmosphere).

The missile based on SFDR fly at supersonic speeds and high manoeuvrability ensures the target aircraft cannot get away.