Since the early 1990's, the United States Air Force has been successfully pursuing advancement in aircraft electrical power system technologies as a means of collectively establishing the capability to reduce dramatically or eliminate centralized hydraulics aboard aircraft and replace them with electrical power as the motive force for all aircraft functions. This overall approach (called the More Electric Aircraft, MEA) has been analytically determined to provide dramatic improvements in reliability, maintainability, supportability and operations/support cost as well as enhancements in aircraft weight, volume, and battle-damage reconfigurability. Historically, the concept of an electrically-based aircraft had been considered by military aircraft designers since World War II, but a lack of electrical power generation capability and the volume of required power conditioning equipment rendered this approach unfeasible. Advances in switched reluctance configuration electric machines and solid state power electronics have now enabled demonstration of an MEA. A time-and technology availability-phased research and development program has been structured to demonstrate the required electrical component and subsystems performance to allow equivalent or improved aircraft performance over the use of hydraulic power. Generation I of the MEA initiative, scheduled for completion in 1998, officially established electrical capabilities toward the elimination of aircraft hydraulics. Generation II of the initiative, with technology availability in 2005, projects such dramatic improvements in electrical power capability so as to provide large quantities (hundreds of kilowatts) of excess onboard electrical power for a variety of revolutionary military functions. This paper provides: 1) a brief historical treatment of technology milestones achieved which enabled the MEA approach; 2) a status of United States Air Force and Department of Defense research and development programs in electrical power generation, distribution, energy storage, systems integration and flight testing; 3) a description of some of the Air Force's planned demonstration activities in aircraft electrical power subsystems; and 4) the dual use nature of many of these technologies enabling a variety of electric and hybrid electrically-propelled military weapon systems and commercial vehicles.
