DARPA’s Hypersonic Vulcan Engine Meld
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GE, United Technologies win Phase II contracts. (July 6/10)
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 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.
What current engines will the Vulcan program modify? What are the program’s goals? What is its structure? DID has answers…
- The Logic Behind Vulcan
- Contracts & Key Events [NEW]
- Additional Readings [updated]
The Logic Behind Vulcan
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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 winning contractors may choose from a number of engine architectures for the CVC portion, such as pulsed detonation engines, continuous detonation engines or other “unsteady” CVC engine architectures. In simplified terms, those “Otto Cycle” CVC architectures burn fuel at a constant volume, with thrust coming from increases in pressure. In contrast, conventional “Brayton Cycle” jet engines burn fuel at a constant pressure, and use the rapidly expanding volume to provide thrust.
DARPA believes that it may be possible to take advantage of each cycle type’s performance strengths, achieving full-spectrum performance and 30-35% gains in fuel efficiency, using a melded “Humphrey Cycle” approach. The Vulcan program envisions a number of possible layouts from side-by-side “dual flow path” turbine and CVC engines, to “annular” systems that share a common fixed air inlet and exhaust nozzle.
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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.
Vulcan’s Phase 1 work involves concept definition. Its most critical element is the firms’ technology development plans, designed to reduce the considerable technical risks inherent in any DARPA project. Key technical challenges include efficient start, low total pressure loss detonation initiation devices, low total pressure loss air valves, thermal management systems, efficient nozzles, and control systems, among others. Despite these difficulties, DARPA is encouraged by recent advances in liquid hydrocarbon/air detonation ignition, low total pressure loss detonation transition devices, air valve and nozzle demonstrations, and computer modeling, measurement techniques.
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DARPA will use the results of the first phase of the Vulcan program to make decisions regarding future phases.
These could include an 18-month 2nd phase for risk reduction testing of full-scale components, which would conclude with a preliminary design review of the CVC demonstration engine. At present, this includes:
- A Systems Requirement Review for the Vulcan Engine;
- CVC module component risk reduction and integration testing;
- Complete CVC Module rig testing with compressor and turbine interfaces, where a CVC Module Simulator is envisioned as a test article to duplicate the unsteady pressure, thermal, and acoustic boundary conditions of the inlet and exhaust of the CVC combustion module and to improve and reduce uncertainty in predictions of Vulcan Engine performance, capability and durability;
- A Preliminary Design Review of the Vulcan Engine.
A 3rd phase would involve 18 additional months (FY 2011-2013) for detailed design, fabrication and demonstration of the CVC engine system. The minimum goal for the end of Phase III is to demonstrate a complete Vulcan engine with the fully integrated CVC module and validate durability, operability, capability and performance at various turbine engine power settings.
A final 18-month 4th phase (FY 2013-2014) would design, build and demonstrate the full Vulcan system.
DARPA’s ultimate hope is to integrate the Vulcan engine into the HTV-3X FALCON/Blackwing vehicle (a.k.a. “SR-72”), and leverage either the engine design or its key concepts and lessons in other full-size hypersonic cruise vehicles.
Contracts & Key Events
July 6/10: General Electric Co.’s GE Aviation Division in Cincinnati, OH, received a $31.7 million cost-plus-fixed-fee contract for Phase II of DARPA’s Vulcan program (see July 2/10 entry for description of DARPA’s Phase II goals). GE will perform the work in Cincinnati, OH (64.1%) and Niskayuna, NY (35.9%), with an estimated completion date of Aug 25/12. Bids were solicited on the web with 3 bids received. The Defense Advanced Research Project Agency in Arlington, VA issued the contract (HR0011-10-C-0115).
July 2/10: United Technologies Corp. in Hartford, CT received a $33.9 million cost-plus-fixed-fee contract for Phase II of the Vulcan Program. They will:
“…further develop constant volume combustion (CVC) technology and culminate in a full scale demonstration of a Vulcan engine – CVC module and power turbine engine – that addresses near-term Department of Defense transition needs… Specifically, Phase II will focus on naval ship-based power generation applications with CVC and an end-to-end demonstration for production turbine with an integrated CVC module… It is expected that the Vulcan Engine design system will be continuously updated with higher fidelity models, component test data, and data from the CVC Module Simulator rig tests to improve and reduce uncertainty in predictions of Vulcan Engine performance, capability and durability.”
Work is to be performed in East Hartford, CT (52.40%); Hartford, CT (34.42T); and Jupiter, FL (13.18%), with an estimated completion date of June 27/12. The Defense Advanced Research Project Agency in Arlington, VA issued the contract (HR0011-10-C-0143). Pratt & Whitney release
Jan 11/10: DARPA issues its #DARPA-BAA-10-11 Vulcan Phase II solicitation via FedBizOpps, and the program is changing tack a bit:
“CVC technology is recognized as having the potential to significantly impact multiple defense and commercial Applications… DARPA is interested in an end-to-end demonstration of a production turbine engine with an integrated CVC Module. DARPA encourages teams to come up with an innovative program plan to quickly mature technology for rapid transition to the U.S. Navy… in turbine engine-based ship power generation systems. Technology developers with expertise in more specific component areas are encouraged to team with a proposer(s) capable of delivering the complete Vulcan Engine (CVC module + turbine engine)… During Phase II the CVC module will be developed, fabricated, tested and fully characterized through analytical models as well as component and subsystem testing prior to the final integration into the turbine engine…”
Aug 14/09: Flight International reports that in December 2009, a classified meeting will be held for the Vulcan program, to present the supersonic powerplant’s configuration to senior military officials.
May 6/09: DARPA anounces Vulcan’s Phase I awards to Alliant TechSystems, General Electric, Rolls Royce, and United Technologies (Pratt & Whitney). Amounts are not disclosed. DARPA [PDF] | UPI | WIRED Danger Room.
Additional Readings
- DARPA – Vulcan Industry Day Presentation [PDF]. Made June 18/08. The most informative public source re: the Vulcan program.
- Pentagon AFPS (Aug 26/09) – Engine Program Aims to Meet Military’s Need for Speed
- FedBizOpps (April 15/09) – Vulcan solicitation announcement
- DARPA (July 30/08) – Vulcan program BAA [PDF]
- CNET (June 24/08) – New brief on DARPA’s Vulcan engine
- Aviation Week’s Ares blog (June 20/08) – DARPA Lifts Cover on Vulcan Engine
- DID – Hypersonic Rocket Plane Program Inches Along. Covers the FALCON(Force Application and Launch from CONtinental USA) HTV(Hypersonic Technology Vehicle). The Vulcan engine, or something like it, will be a key component for the HTV-3X “Blackwing,” which would bring the FALCON program close to its goal of an operational vehicle.
- DID Spotlight – Australia, USA Collaborating on Hypersonic Research (updated). Details the $54 million HIFiRE program, which is making significant contributions to hypersonics research.
