Raytheon, an RTX business, has received a $29-million cost plus fixed fee contract from the Defense Advanced Research Projects Agency (DARPA) to develop Gambit, an air-breathing propulsion demonstration program that uses a novel rotating detonation engine (RDE). This type of engine is more compact, provides a higher efficiency propulsion source than conventional missile propulsion and offers the potential for lower costs.
Rotating detonation engine (RDE) concepts have been studied since the early 1960s, largely focused on gaseous mixtures as fuel. (Earlier post.) Unlike conventional gas turbine engines, which rely on subsonic constant pressure combustion, RDEs leverage high-intensity, self-sustaining detonation—a supersonic reaction wave coupled with a shock—rapidly to consume the fuel-air mixture, typically in a ring-shaped, cylindrical chamber (earlier post).
With RDEs, there is an effective pressure gain; the intense and rapid energy release from detonation can be used to generate extremely high thrust from a relatively small combustor.
RDEs can offer higher thermodynamic efficiency than traditional engines due to the rapid and complete combustion process of detonation. RDEs can also be more compact and lightweight compared to traditional engines, making them suitable for applications where space and weight constraints are critical. Detonation combustion can produce fewer emissions compared to conventional combustion processes.
Gambit is a first-of-its-kind engine development program that could support future weapons systems for multiple military services. The compact nature of the engine and its efficient combustion provide a boost in range and speed relative to current long-range weapons, allowing the ability to quickly respond to advanced threats.
This is a revolutionary propulsion system. We’re leveraging existing digital design tools and experience from across the entire RTX business to rapidly prototype this next-generation strike weapon and mature the technology.—Colin Whelan, president of Advanced Technology at Raytheon
Under the contract, RTX will rely heavily on iterative development of performance models which will be anchored by real-world data from incremental system tests. This proven method accelerates learning to provide more certain flight test outcomes, saving both time and cost. Future optional phases of the Gambit program will shift to building hardware to conduct a flight weight free-jet test.
With this contract, RTX becomes the first company to apply rotating detonation engine technology into an actual test system.
RTX—which includes Collins Aerospace, Pratt & Whitney, and Raytheon—is the world’s largest aerospace and defense company with more than 180,000 global employees.