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By:

Commodore S.L. Deshmukh

31 October 2024 at 8:30:19 am

The Detonation Race Is On

Rotating detonation engines could redefine propulsion in the near future, and India cannot afford to be a bystander For more than a century, the basic architecture of the jet and rocket engine has remained remarkably resilient. Fuel is burned, gases expand and turbines, compressors or other components turn that energy into thrust. Now, a different idea is beginning to move from laboratories towards operational propulsion: the rotating detonation engine (RDE). It replaces conventional...

The Detonation Race Is On

Rotating detonation engines could redefine propulsion in the near future, and India cannot afford to be a bystander For more than a century, the basic architecture of the jet and rocket engine has remained remarkably resilient. Fuel is burned, gases expand and turbines, compressors or other components turn that energy into thrust. Now, a different idea is beginning to move from laboratories towards operational propulsion: the rotating detonation engine (RDE). It replaces conventional combustion with a continuously travelling supersonic detonation wave, promising greater efficiency in a smaller and mechanically simpler package. If propulsion is a contest between how much energy can be extracted from fuel and how little machinery is required to do it, RDEs have an intriguing advantage. An RDE works inside an annular, or ring-shaped, combustion chamber. Fuel and oxidiser are injected into the chamber and ignited. Instead of a conventional flame moving relatively slowly through the mixture, a detonation wave races around the chamber at supersonic speed. The wave compresses and ignites fresh fuel as it travels, creating a self-sustaining cycle. The resulting high-temperature gases are expelled axially, generating continuous thrust. Improving Fuel Efficiency That is fundamentally different from the combustion process used by traditional engines. Conventional gas-turbine engines operating on the Brayton cycle rely on subsonic deflagration - a rapid burning process in which the flame front travels through the combustible mixture at less than the speed of sound. RDEs generally operate on the Humphrey cycle, using pressure-gain combustion to extract more useful energy from the chemical reaction before the gases are expelled. Detonation-based combustion has the potential to improve fuel efficiency by as much as 25 percent compared with conventional engines. RDEs can also dispense with some of the heavy and complicated moving machinery associated with traditional propulsion systems. That creates the possibility of engines that are smaller, lighter and easier to manufacture. For missiles and rockets, where every kilogram matters, such advantages are particularly valuable. The appeal extends beyond efficiency. A continuously propagating detonation wave can provide steady thrust while eliminating the need for a conventional turbine-compressor architecture. The result could be a propulsion system suited to hypersonic missiles, high-speed aircraft, space vehicles and other platforms where compactness and performance matter as much as raw power. That said, maintaining a smooth and stable detonation wave is extraordinarily demanding. Fuel injection must be precisely controlled and the geometry of the combustion chamber carefully engineered. The number, spacing and shape of injectors can determine whether the detonation remains stable or breaks down. Inside the chamber, extreme temperatures and pressures place enormous demands on engine walls, requiring advanced cooling systems and high-performance materials. These engineering problems explain why the RDE revolution has been promising for years without yet becoming routine technology. The challenge is no longer simply demonstrating that a detonation can be sustained. It is turning that phenomenon into a reliable, durable and flight-ready propulsion system. Production Race The United States is pushing ahead on several fronts. NASA has successfully tested full-scale RDEs producing more than 5,800 pounds of thrust and is planning to raise that figure to 10,000 pounds for potential lunar and Mars missions. Pratt & Whitney, part of RTX, has conducted extensive RDE testing for military applications, exploring high-speed and long-range propulsion with a simpler architecture. DARPA is pursuing RDE technology for hypersonic standoff missiles under its Gambit programme, while L3Harris has conducted long-duration, full-scale tests aimed at advancing next-generation missile propulsion. The international competition is broader still. Japan’s JAXA, GE Aerospace and Chinese institutions have been pursuing RDE applications in rockets and hybrid air-breathing engines, including systems intended for hypersonic flight. China, in particular, is treating the technology as part of its broader push towards high-speed aerospace and military systems. Researchers at Tsinghua University introduced a hybrid design in 2024 combining a ramjet with a rotating rotor compressor, intended to improve starting at lower speeds and enhance performance during flight. In 2025, scientists at the Beijing Power Machinery Research Institute reportedly completed a milestone test of an RDE operating steadily for 180 seconds at Mach 6.3. Recent Chinese test engines have also reportedly incorporated specialised materials capable of tolerating internal temperatures of up to 2,500°C. For India, therefore, RDEs are no longer merely an interesting engineering experiment but are fast becoming part of the strategic propulsion race. India has already taken an important step. Defence propulsion start-up D-Propulse, incubated at IIT Madras, has demonstrated what it describes as the country’s first indigenous 5 kN air-breathing RDE coupled with an aerospike nozzle. The hot-fire demonstration was conducted at a DRDO test facility and reportedly achieved Technology Readiness Level-5 validation in the specified environment. That matters because it represents a movement from laboratory research towards an integrated propulsion prototype. D-Propulse has stated that it is targeting a flight-ready engine by December 2027. The company says its technology can deliver 15–25 percent higher thermodynamic efficiency than conventional air-breathing propulsion systems and can be produced through precision machining rather than complex turbine assemblies, potentially reducing both production costs and lead times. The applications could be considerable. Defence systems could include hypersonic missiles, air-to-air and air-to-ground weapons and compact propulsion systems for standoff strike platforms. In space, RDEs could find uses in upper-stage rocket engines, planetary landers and deep-space propulsion, where higher efficiency and lower engine mass are particularly valuable. The technology could even migrate beyond aerospace: RDE-based gas turbines could potentially generate electricity with greater thermal efficiency and lower fuel consumption. The larger significance is that propulsion technology often determines what a country can build, how far it can travel and how quickly it can respond. RDEs remain an emerging technology, and their promise should not be confused with operational maturity. But countries that solve the problems of stability, materials, cooling and reliable fuel injection first could gain an important advantage in the next generation of aerospace and defence systems. (The writer is a retired naval aviation officer and a defence and geopolitical analyst. Views personal.)

Why is Mamata Seeing Ghost of Bangladesh?

Updated: Oct 21, 2024

Why is Mamata Seeing Ghost of Bangladesh?

Mamata is seeing a ghost of Bangladesh behind the massive outrage and waves of protest over rape and murder of the trainee doctor. And the reasons are many.

It’s been over a fortnight. Yet with each passing day the voice of protest is getting louder and stronger. From the streets of Kolkata it’s pouring into roads of hinterland. The cry for justice for a rape victim has consolidated into a wail of demands to set a lot of wrongdoings right. Here in lies the fear and trepidation. Wasn’t the issue that brought the youth of Bangladesh out on the thoroughfares a simple, innocent one of quota reform?

The chief minister of Bengal, known for understanding the pulse of people better than many, was quick to read the signages floating in the political horizon.

The most obvious reason for her to be tensed is that both the regime change in Bangladesh and the mass protest in Bengal, were student-driven to begin with. The two incidents---end of 15 year old Sheikh Hasina government and turbulence in West Bengal, over the heinous crime, falling back to back, the first on August 5th and the latter from August 9th onwards, give natural scope for comparisons. More so, because in both the cases the movement strayed beyond an affected constituency to include aggrieved people at large, cutting across socio-economic demography. If the quota reform protest started by students in Bangladesh became a mass uprising against an autocratic regime, the campaign demanding justice for the rape victim and overall safety and security of women in Mamata Banerjee’s Bengal soon snowballed into a movement of no-confidence against the government. Slogans--”Mamata must resign” also got floated in social media much in line with the call for ouster of Sheikh Hasina. In fact “Resignation of Hasina” became the single point agenda into which all other fringe demands coalesced.

Incidentally, even before people started drawing parallels, that there could be a thread of commonality in the way the upheaval in Bangladesh and Bengal played out, Mamata was quick to point out that the Opposition were trying to pull off a Bangladesh by politicizing the tragic incident: “A coordinated approach has been executed by the BJP and the CPIM with support from the Centre to defame Bengal and exploit the situation....They want to make a Bangladesh here. They are taking cues from student unrest in Bangladesh and are attempting to capture similarly. I have no longing for the chair. I came here to serve people.”

Not only Mamata, her political lieutenants are consistently equating the turmoil in Bengal with the mayhem in Bangladesh. Cabinet minister for North Bengal development Udayan Guha threatened to take stern action against those, who would be trying to exploit the situation by emulating a Bangladesh like movement. “ Even after the hospital was vandalised, the police did not open fire on anyone. The police will not allow a Bangladesh type situation. We will not allow Bengal to turn into Bangladesh, Guha thundered.

Is the government’s fear unfounded?

Apart from the similarities on ground zero, as to how and where the future course of events are heading to, there are ample reasons for Bengal to mull on-- as to what led to a Bangladesh like boiling point. To begin with, it’ll be appropriate to talk of Bangladesh and the prevailing situation, that made the students’ protest become big in magnitude. The students were out on the streets because of a high reservation in public jobs. Unemployment and stagnant job market in private sector coupled with a high rate of inflation drove the educated youth to rebel against the government.

But soon the students found enormous number of sympathisers, who were equally at the receiving end. According to Bangladesh citizens, the last two terms of the Sheikh Hasina government were a mockery of democracy. Even elections would be compromised. As Hasina grew from strength to strength, she politicized institutions. The rank and file of police owed allegiance to the ruling dispensation. Extortion, harrassment and raids by police and people in power became rampant. An atmosphere of fear and repression reigned and people got restless to overthrow the government.

Politicization of institutions has been happening in Mamata government too. Allegations are quite strong that police in Bengal functions at the beck and call of political bosses. The lapses and alleged loopholes on the part of police in handling the rape and murder of the young doctor have yet again revealed a sense of confused or misplaced loyalty.

But above everything else both Hasina and Mamata governments allegedly seem to have twined in accepting corruption as a way of life. In Bangladesh jobs of primary and secondary teachers got sold at premium, Rs 10-12 lakh in the Hasina regime. Even police had to pay up for prized postings and transfers. In Bengal busting of the teacher’s recruitment scam has revealed how unsuccessful and ineligible candidates got government jobs in schools in exchange of bribes.

Similarities are multiple and inescapable. Mamata has good reasons to be apprehensive. It’s not only she, who can see and connect the dots. People, out on the streets, clamoring for justice, can see a providential pattern somewhere in the unfolding of future events in these two places-- Bangladesh and Bengal. True, they share more than 2,217 odd km of border. They share the same umbilical cord, other than language, culture, ethos, icons. Even emotions are the same. So she cannot take any risk.

(The writer is a senior jounalist based in Kolkata. Views personal)

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