DARPA’s Vulcan Engine Aims for Mach 6+

DARPA’s Hypersonic Vulcan Engine Meld
Defense Industry Daily

It might not be a Vulcan mind-meld, but it’s pretty close. The Department of Defense’s technology brain trust, the Defense Advanced Research Projects Agency (DARPA), has given 4 contractors the go-ahead to develop the advanced Vulcan combination engine system for hypersonic flight. The 8-month first phase features awards to: Alliant TechSystems, General Electric, Rolls Royce, and United Technologies.

The Vulcan engine will integrate a traditional jet turbine engine that performs well at low speeds, with a constant volume combustion (CVC) engine that performs well at higher speeds. The combination will help the vehicles go from standing starts to Mach 4 or so, where hypersonic engines can take over. DARPA’s ultimate goal is to design, build, and fly Mach 6+ re-usable, air-breathing, turbine-based hypersonic vehicles….

Contractors will use an in-production turbine engine that is capable of operating at or above Mach 2, such as United Technologies’ subsidiary Pratt & Whitney’s F100-229 (in F-16/F-15 fighters) and F119 (F-22A) engines, and GE’s F110-129 (F-16/F-15) and F414 (F/A-18E/F, JAS-39NG) engines. The hope is that picking a proven high-Mach conventional engine will save a lot of money and time, as opposed to past efforts that have tried to develop an entirely new conventional engine for use in hypersonic mixed-cycle systems….

The idea is to use conventional jet engines for takeoff, use the combined engines to get up to speed, then switch to CVC/scramjet-only power during hypersonic flight above Mach 4. At those speeds, the conventional turbine will need to be “cocooned,” in order to protect its components from the high heat and pressures generated by hypersonic speeds in the atmosphere. Full low-altitude spaceflight would add an additional set of complications, including the need for cryogenic fuels, for materials that can withstand a broader range of extreme environments during flight and re-entry, and for engines with even broader performance ranges.

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