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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.)

What India Must Do to Reach the WTC Final

India sit fifth in the 2025-27 World Test Championship standings with 68 points from 11 matches and a points percentage of 51.52. That figure places them behind Australia (80 per cent), South Africa (75), New Zealand (72.22) and Bangladesh (55.56). Only the top two teams at the end of the cycle will contest the 2027 final. With seven Tests remaining — two away to New Zealand in November and five at home against Australia from late January to early March — the path is narrow, demanding and entirely within India’s control only if results are near-perfect.


Points are awarded 12 for a win and four for a draw. India’s maximum possible return from the remaining fixtures is 84 points, which would take their overall tally to 152 from 216 points available and a percentage of approximately 70.37. Anything short of that ceiling forces them to rely on other teams dropping points. History from the previous cycle shows finalists finishing above 67 per cent. India must therefore treat every remaining match as a must-win contest while maximising home advantage against Australia.


Scenario 1: The Clean Sweep Path (Most Viable Route)

India win both Tests in New Zealand and then take the Border-Gavaskar series 5-0 or 4-1. A 2-0 result in New Zealand would immediately lift the percentage into the high 50s or low 60s, depending on exact calculations after those matches. Completing the job with four or five wins at home against Australia would push the final percentage into the 65-70 range. This is the only scenario that places qualification largely in India’s hands. It requires clinical batting first innings totals above 350 on most occasions, disciplined bowling that takes 20 wickets on turning tracks, and zero tolerance for soft sessions. New Zealand’s home strength makes the away series the sterner immediate test; Australia’s quality means India must prepare pitches that offer consistent turn and bounce from the outset rather than waiting for the fourth day.


Scenario 2: The Narrow Qualification Window

India drop one Test in New Zealand but still win five of the remaining six matches overall (one win in New Zealand plus four or five against Australia). The resulting percentage would likely settle in the low-to-mid 60s. Qualification then becomes contingent on results elsewhere: South Africa or New Zealand must lose series points against Australia, England or each other, and Bangladesh must not keep winning at a high rate against weaker opposition. This scenario is mathematically possible but strategically fragile. It leaves India hoping for favourable outcomes rather than dictating them. One more draw or loss against Australia would push the percentage below the historical threshold needed for a final berth.


Scenario 3: The Elimination PathAnything fewer than six wins from the seven remaining Tests effectively ends the campaign. A 1-1 draw in New Zealand followed by a 3-2 home series against Australia, or worse, would leave India with a percentage in the mid-to-high 50s. At that level they would be overtaken or held off by the teams currently above them. Draws that feel respectable in isolation become costly under the percentage system. Losses at home against Australia would be particularly damaging because they simultaneously hand points to a direct rival and waste India’s strongest remaining fixture list.


Beyond the arithmetic, the cricket itself must improve in specific areas. The top order needs greater first-innings consistency; repeated collapses below 250 have already cost percentage points this cycle. The lower order must contribute more regularly with the bat. Bowling groups must maintain length and control on surfaces that deteriorate, converting pressure into wickets rather than allowing opposition lower orders to recover. Fielding standards cannot dip for even one session. Selection must prioritise current form and conditions over reputation, ensuring the best available combination for spinning tracks at home and the varied challenges of New Zealand.


India have reached the last two WTC finals. The talent remains, and the five-Test home series against Australia offers a genuine opportunity to control destiny. Yet the current position leaves no room for the mixed results that characterised parts of the first half of the cycle. The team must approach the New Zealand tour with the intensity of a final and the Australia series with the ruthlessness of a side that understands every session carries championship weight. Only sustained winning performances, not optimistic calculations about other results, will deliver a place in the 2027 final. The mathematics are clear. The execution must now match them.


(The writer is a senior journalist based in Mumbai.)

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