Hypersonic missiles, capable of reaching speeds five times faster than the speed of sound, offer a challenging potential for existing defense infrastructures due to their ability to cover very long distances in very short periods. This is why countries like the USA, China, and Russia are continuously working to strengthen their capabilities in this field. News this week indicates that the USA is on the verge of a significant breakthrough in this area.
GE Aerospace and Lockheed Martin publicly shared a new engine concept that could shape the future of hypersonic flight, following a propulsion demonstration. The companies aim to close the efficiency gap, one of the most fundamental problems of hypersonic systems, by combining a liquid-fueled rotating detonation engine (RDE) with a dual-mode ramjet air intake. This new approach is seen as a significant step towards increasing engine performance, especially at speeds above Mach 5.
Today, many hypersonic missiles rely on ramjet engines for high-speed cruise. These engines, which have no moving parts, use the vehicle's forward speed to compress air, allowing them to operate very efficiently at high speeds. However, the biggest drawback of ramjet engines is the requirement for the vehicle to already be traveling at approximately Mach 3 to start operating. This necessitates launching missiles with large and heavy rocket boosters. These boosters both limit range and increase cost and design complexity. This problem, referred to as the "efficiency gap," has long been one of the fundamental obstacles that hypersonic systems have been unable to overcome.
GE Aerospace's rotating detonation engine offers a radical alternative at this point. While traditional engines consume fuel through a constant combustion process, in this new engine concept, combustion occurs via a continuously rotating supersonic detonation wave within a cylindrical chamber. Fuel and oxidizer feed this detonation wave, creating a self-sustaining, high-pressure cycle. This method provides an efficiency increase of up to approximately 25% compared to conventional combustion systems. Furthermore, the engine's smaller and lighter design offers an advantage that could fundamentally change the overall design of hypersonic systems.
Hypersonic Missile Range Can Increase Thanks to More Compact Design
Another critical feature of this engine is its ability to operate at low speeds. Unlike conventional ramjet engines, rotating detonation engines can sustain combustion even before reaching supersonic speeds. This allows for launches with smaller rocket boosters, and in some scenarios, significantly reduces the need for boosters altogether. The ability of the same engine core to operate in both ramjet and scramjet modes provides a much smoother transition between speed regimes throughout hypersonic flight.
Lockheed Martin's contribution to this project comes with a new tactical air intake designed for dual-mode flight. Controlling airflow at hypersonic speeds is an engineering problem as complex as the engine itself. Shock waves generated at Mach 5 and above must be managed within very narrow tolerances. Lockheed Martin's new air intake regulates airflow in a manner compatible with the rotating detonation engine under varying speed and altitude conditions, ensuring stable combustion. This design specifically aims to reduce performance fluctuations experienced by detonation engines in different atmospheric conditions.
New Propulsion System Could Also Be Used in Future Hypersonic Aircraft
This combined system has the potential to make hypersonic propulsion more compact, lighter, and more cost-effective. Smaller rocket boosters mean longer range and more flexible mission profiles. Randy Crites, Vice President of Lockheed Martin Advanced Programs, emphasizes that this demonstration, following two years of internal investment, marks a significant turning point for bringing hypersonic capabilities to the field more rapidly and economically.
Should the technology continue to mature, this approach could play a central role not only in next-generation hypersonic missiles but also in future hypersonic aircraft and other high-speed platforms. While still in its early stages, the new propulsion concept presented by GE Aerospace and Lockheed Martin indicates that the boundaries of hypersonic flight could be redefined.
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