The restart of the DD(X) surface combatant program following the General Accounting Office's August decision to deny General Dynamics' protest of the Navy's DD(X) contract award in April to the Gold Team will speed the pace of industry work on shipboard integrated electric drive.
The progress on the DD(X) electric-drive work, industry and Navy officials say, also will push forward a broad move not only toward electric drive for ships and submarines, but also toward a range of electric machinery for other defense applications. The Navy's Virginia (SSN-774)-class attack submarine program envisions introducing electric drive in the 2010 time frame. The Army plans to move to electric drive for future ground vehicles.
The Gold Team, led by Northrop Grumman and Raytheon, is proceeding with work on ship-system design, aimed at completion on the original pre-protest schedule of 2005. Electric drive, anointed with great fanfare by Secretary of the Navy Richard Danzig in January 2000 as the baseline power architecture for the program (then called DD-21), almost certainly will be the most decisive new engineering venture for the ship-driving Navy in years.
The Navy has wrestled with electric drive for more than two decades. Integrated electric drive, which postulates a single suite of electric motors and prime movers for propulsion and ship-service power, eliminates the need for a reduction gear and a lengthy propeller shaft, permitting considerably enhanced fuel economy and flexibility for ship design. In a September 1988 speech, Chief of Naval Operations Admiral Carlisle Trost said, "I am declaring that integrated electric drive, with its associated cluster of technologies, will be the method of propulsion for the next class of surface battle force combatants, and I am directing all the major Navy organizations involved in these efforts to concentrate their energies toward that objective."
Navy enthusiasm for electric drive, as well as funding, ebbed in the early 1990s, although low-level research continued. Electric drive, meanwhile, now is widely employed on board cruise ships, primarily in hybrid electrical-mechanical configurations.
Kaman Aerospace, at its Electromagnetics Development Center in Hudson, Massachusetts, is teamed with Northrop Grumman Newport News for the design and prototyping of the electric propulsion motor that represents the heart of integrated electric drive for DD(X). Power Technology Inc., in collaboration with Kaman, will carry out the large-scale fabrication and assembly at its Fitchburg, Massachusetts, plant, formerly used by General Electric to build Navy steam turbines.
Kaman's design will build on the company's permanent magnet motor technology, already widely used in the oil and gas business to drive drill pipe though rock and soil. The company says its commercial permanent magnet motors have logged more than one million operating hours without maintenance. Kaman, teamed with Flowserve Corp., won a Naval Sea Systems Command contract to provide 18 pumps powered by permanent magnet motors for shipboard use. Kaman also is under contract to support selection of electric-traction motors and vehicle power generators for the Army's future combat system. Kaman and other companies are considering opportunities for electric drive for the Navy's littoral combat ship.
The DD(X) permanent magnet motor will be a brushless DC motor that will be installed within the ship's hull. For the Blue Team, General Dynamics had proposed a design for a podded propulsor that would be fitted externally to the ship's hull. Industry and Navy officials say, however, that the podded approach probably represented a degree of the technical risk that the program's executive office for surface strike, which runs the DD(X) effort, was not ready to accept.
Gold Team officials say the DD(X) design includes segmented stators and modular drive components that can be manufactured, installed, and replaced individually to simplify construction and repair and to support future upgrades. Power requirements will be demanding—program officials are discussing performance parameters in the range of 30 megawatts and they are "still going up," officials say.
Kaman and its teammates will deliver two prototype motors and drives for land-based and at-sea testing. The company is evaluating the capabilities of suppliers nationwide for production of motor electronics modules and stator segments. Officials say the company has no firm timetable for selecting production partners.