TECHNOLOGY AREA(S): Air Platform
OBJECTIVE: Develop and demonstrate lightweight, durable, high power density electric motor technologies for main/auxiliary propulsors to enable future turbo-generators to power DoD Group 2/small Group 3 unmanned aerial systems (UASs) for increased reliability and operational capability.
DESCRIPTION: Tactical requirements for unmanned aerial systems are exceeding current capabilities for performance (payload, range), reliability, maintainability, detectability, and supportability. Mission requirements such as increased power, extended endurance, low altitude maneuverability in urban environments without detection, increased tactical capability, and high reliability are becoming paramount. These combined requirements are currently not fully realized with conventional rotary, internal combustion, or turbine-based propulsion architectures. Improved engine reliability is a critical need area. Electrical power requirements for advanced payloads is also increasing, which adds weight to the air vehicle. Micro-Turbine based hybrid more-electric architectures offer the potential for a new paradigm for increased UAS system level flexibility, efficiency, readiness level, weight reduction, reliability, mission capability, and survivability. A weak link in this type of hybrid architecture is the electric motor drive. Improvements in electric motor performance at lower power settings while addressing thermal issues are needed. The following goals/metrics will be followed: motor input voltage will be 270VDC; nominal output RPM will be 3200-3500 rpm; Continuous Shaft Power at Nominal RPM will be 20HP; weight goal is less than or equal to 6lbs; motor efficiency goal is greater than or equal to 95% at 50-100% power and 90-95% at 25-50% power. The electric motor will be air cooled and operate up a pressure altitude of 18,000 feet without detrimental effects to its operation. Additionally, the motor will be required to pass MIL-STD-810G testing for altitude, high and low temperatures, rain, sand and dust, and salt fog at a minimum. The resulting advanced electric motor propulsion system would need to be able to meet different operational requirements of a Group 2/small Group 3 UASs, which include full power takeoff capability, high part-power efficiency for improved cruise endurance, and quiet operation capability.
PHASE I: During the Phase I effort, the electric motor should be designed, fabricated and validated to substantiate the ability to provide a lightweight, low cost, and durable/reliable system that can be integrated into a current and future 5-20 HP micro-turbine/more electric hybrid UAS systems.
PHASE II: Phase II will fully develop, fabricate, and demonstrate the electric motor, in a bread-board simulated UAS environment. Various realistic mission profiles will be used during testing. Environmental tests will be executed. Additional validation to be performed at an Army facility to corroborate evidence of performance goals.
PHASE III: Phase III options should include endurance testing and integration of the enhanced hybrid propulsion system into an appropriate UAS airframe and demonstrate the performance of the advanced electric motor/system with flight testing in a UAS mission environment. DUAL USE COMMERCIALIZATION: Military Application: UAS performing Intelligence, Surveillance and Reconnaissance (ISR), targeting and target acquisition missions. Commercial Application: Law enforcement, Homeland Security, and emergency service Unmanned Air Systems performing intelligence, surveillance, search and rescue, and disaster relief missions.
1: Petro, John, 2011, "Achieving High Electric Motor Efficiency", EEMODS 2011Energy Efficiency in Motor Driven Systems, Paper 060, European Commission, Luxenbourg, EU
2: Macheret, J., Teichman, J., and Kraig, R., 2011, Conceptual Design of Low-Signature High-Endurance Hybrid-Electric UAV, Institute for Defense Analysis (IDA), IDA Doc NS D-4496, Washington D.C.
3: Harrop, P., Harrop, J., 2015, Electric Drones: Unmanned Aerial Vehicles (UAVs) 2015-2025, ID Tech Exchange, Automotive & Electric Vehicles Report, Cambridge, MA
4: Bullis, Kevin. 2015, Hybrid Power Could Help Drone Delivery Take Off, MIT Technology Review, Cambridge, MA
KEYWORDS: Unmanned Aerial System, Electric Motor, Micro-turbine Engine, Electric Hybrid Propulsion, Heavy Fuel Engine, Electric UAS