Earlier today, a missile airframe integrated with a solid fuel ducted ramjet (SFDR) propulsion system was tested by India’s Defence Research and Development Organization (DRDO). Unlike an earlier test in May 2018, when only the nozzle-less booster of the SFDR configuration was validated, today’s exercise was an ‘all-up’ trial, wherein the ramjet sustainer of the missile ‘kicked-in’ after it had been accelerated to a certain forward velocity by the nozzle-less booster. Although, the missile was launched from the ground with the help of a ground-launch (GL) booster (not to be confused with the nozzle-less booster that is inside the missile airframe), it is actually an early iteration of a beyond visual range air-to-air missile (BVRAAM) system intended for long-range engagements.
According to India’s Ministry of Defence, in today’s test “Ground booster, separation of ground booster and Nozzle-less-booster performance were found satisfactory”. Also, the missile was “guided to a high altitude to simulate aircraft release conditions and subsequently the nozzle-less-booster was ignited. The SFDR based missile accelerated to achieve ramjet Mach number successfully. The trajectory was tracked by telemetry and radar stations till touchdown.”
File image of the SFDR powered missile being launched. The solid rocket GL-booster is clearly visible and has just undergone ignition. Source: Government of India.
The SFDR used in today’s missile achieves thrust modulation using a hot gas flow controller (valve) as depicted in the image below. The fuel rich grain is likely a boron based nano-fuel with metal additives. The overall scheme involves the use of a ‘reduced smoke’ nozzle-less rocket booster to first accelerate the missile to a certain Mach number at which the ramjet sustainer can achieve ignition and start delivering thrust. It is the ramjet which then propels the missile at high supersonic speeds for engaging targets at extended ranges. According to DRDO sources, in today’s test the missile achieved a sustained speed of close to Mach 3 thanks to the successful operation of its ramjet.
The above image is from a publicly released DRDO tender.
With today’s successful test, the stage is set for the emergence of indigenously developed very long range AAMs, since India might now have a credible air-breathing propulsion system (i.e. the SFDR) on its hands to power the same. The SFDR project began in February 2013 for a sanctioned cost of Rs 366 crores with DRDO’s Defence Research & Development Laboratory (DRDL), Hyderabad, being made the lead agency for its development. The project budget has since been revised to Rs 494 crores, with the deadline for completion set as May 2020. As such, it is reasonable to expect that SFDR testing will now gather pace in order to complete the project by next year.
In the past, DRDO has revealed that it has been working on active electronic scanned array (AESA) seekers and a SFDR propelled AAM equipped with an AESA seeker would certainly be a daunting proposition for the Indian Air Force’s rivals. Such a missile, if successfully developed, would in theory match the capabilities of the much sought after MBDA Meteor BVRAAM.
Saurav Jha is the Editor-in-Chief of Delhi Defence Review. Follow him on Twitter @SJha1618
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