Engine maker GE Aerospace and defence manufacturer Lockheed Martin have teamed up to test a novel ramjet propulsion system for powering hypersonic flight.
The pair say they completed a series of demonstrations with a liquid-fuelled rotating detonation ramjet engine that could be used to propel missiles to Mach 5 and beyond – the generally accepted threshold for hypersonic flight.
The new engine combines GE’s rotating detonation engine technology with a specialised air intake developed by Lockheed that allows for high-speed airflow into the combustion chamber.
Rotating detonation combustion (RDC) offers significantly improved fuel efficiency with fewer complex moving parts than traditional turbofans or ramjet engines. The process uses a continuous wave of combustion travelling circularly around an enclosed chamber, into which fuel is injected.
GE Aerospace has spent years developing novel RDC engines that can ignite at lower speeds than traditional ramjet and scramjet engines, while still producing sufficient thrust to power hypersonic flight.
The propulsion system being developed with Lockheed will offer improved fuel efficiency and better range in a smaller package, along with lower production costs, as compared to existing ramjet designs, the companies say.
Testing of the new air-breathing RDC ramjet was conducted at GE’s Aerospace Research Center is Niskayuna, New York.
Engineers at the site evaluated the design under conditions of initial ignition and high-speed cruising by injecting air into the inlet to simulate supersonic fight at various speeds and altitudes in laboratory setting.
“Following two years of internal investment, this demonstration is a testament to the power of collaboration, innovation and joint commitment to get affordable capability into the hands of warfighters,” says Randy Crites, general manager of Advanced Programs at Lockheed.
Notably, the experimental propulsion system is compact enough to be compatible for use in missile systems.
During a 2023 tour of the GE Aerospace Research Centre, company officials told FlightGlobal the RDC engine technology is platform-agnostic and scalable, to include potential applications for future crewed aircraft designed for high-Mach flight.
“GE Aerospace’s hypersonic capabilities continue to advance at a rapid pace, and this collaboration with Lockheed Martin is another step forward in our journey,” says Mark Rettig, general manager of the engine maker’s Edison Works advanced projects unit.
“The testing on the rotating detonation ramjet and inlet exceeded expectations, and we are excited about this collaboration to continue maturing our advanced air-breathing hypersonic propulsion technologies,” he adds.
Hypersonic weapons offer the prospect of being able to deliver a lethal strike at speeds that exceed the ability of traditional air and missile defence systems to effectively counter.
Russia and China took an early lead in developing hypersonic weapon systems, while the USA has attempted to narrow that gap by investing with both traditional aerospace manufacturers and new start-ups.
Military engine maker Pratt & Whitney is testing its own rotating detonation engine for powering hypersonic missiles, while start-ups such as Stratolaunch and Hermeus are developing reusable aircraft capable high-Mach flight.
GE Aerospace and Lockheed Martin say they will continue maturing their RDC ramjet engine throughout 2026.
