DARPA has contracted Raytheon to develop a practical version of a revolutionary air-breathing rotating detonation engine called Gambit, which would have no moving parts and could lead to lighter missiles with longer ranges at lower cost.
Gas turbines are remarkable power plants that have made possible modern air travel and many weapon systems, but they suffer from a number of disadvantages. They are complex machines that are heavy, have many moving parts that are costly to assemble and maintain, and they require exotic materials and special processing to handle the tremendous temperatures they operate at.
It's bad enough when such an engine is installed in an aircraft, but when it's part of a throwaway weapon like a cruise missile, this not only limits the payload, it runs into some serious money.
One alternative is the Rotating Detonation Engine (RDE), which replaces the complexities of the turbine with a peculiar property of burning fuel/air mixtures.
In an RDE, a combustible mixture of fuel and air is introduced into a gap between two coaxial cylinders, with the gap sealed at one end and the other end forming into a nozzle. When the mixture is ignited, it burns in a very special way. The combustion takes the form of a supersonic wave that travels around inside the gap. As more fuel and air is introduced at the top, the wave continues going around in the gap, producing more and more heat and pressure, and is forced down until it exits through the nozzle, creating thrust.
Such an engine has a number of obvious advantages. They are simple in design, are hard to disable, easy to mass produce inexpensively, don't require exotic metals and ceramics, and are lightweight and compact. They can also be configured with ramjets, gas turbines, and rockets for a wide range of possible applications.
The problem is to take the RDE from the test benches, where they've dwelt in recent years, and create a functioning demonstrator. Under the DARPA contract, Raytheon will develop the Gambit engine through a series of iterations until it comes up with a design that can be adapted to future military weapon systems, especially new stand-off missiles to keep fourth-generation fighters relevant to the 21st century battlefield.
Currently, the project is in Phase 1, which covers preliminary design of the engine and its primary components. Phase 2 will deal with fabrication and testing of the actual engine. The ultimate goal will be to come up with an RDE that can be fitted to future prototype weapon systems.
"This is a revolutionary propulsion system," said Colin Whelan, president of Advanced Technology at Raytheon. "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."
Source: Raytheon
