1 Hybrid-Electric Propulsion System Conceptual Design Challenges Reed Danis Aerospace Engineer Empirical Systems Aerospace, Inc. (ESAero) San Luis Obispo, California Work performed in cooperation with NASA Ames Funded under NASA Phase II SBIR NNX15CA13C COR: Gloria Yamauchi Presentation For: AHS International 5 th Transformative Vertical Flight Workshop
2 Who s ESAero: How We Got Here 10 Years of eairplane Development - Design AS an Enabling Technology ECO-150R ECO-150 Hybrid-Electric Rotorcraft Timeline Approximate & Not to Scale AFRL TeDP Dual-Use LEAPTech X-57 Maxwell 2008 2012 2013 2014 2015 2018
3 Hybrid-Electric Rotorcraft (HERC) Project (2014-2017) Relevant HERC Objectives: Develop design tools Explore design space Perform initial sizing Investigate system-airframe integration Focus: Pushing the capabilities of the sizing tool
4 Overview of PANTHER Aircraft Design Tool Propulsion Airframe integration for Hybrid Electric Research: Multiple vehicle sizing modes Propulsion & TMS component sizing with multi-point on-design Supports unique architectures & configurations Easily swap sizing/analysis methodologies of components Capture of Propulsion-Airframe Integration (PAI) effects Mixed-fidelity analysis fidelity grows with designer knowledge
5 Hybrid Propulsion: Decoupled Energy Management Unique design characteristics Potential benefits for future vehicle designs Decoupled power and energy management Flight Envelope Excursions Combine Strengths of Different Technologies Benefit From Future Technology Improvements Enable Future Transformative Concepts Facilitate Distributed Propulsion Must overcome technical and conceptual challenges to realize benefits
6 Challenge: Adapting Design Tools for Hybrid Air Vehicles Conventional Fuel Flow vs. Airspeed Need to adapt design tools for multiple energy-source hybrid-electric vehicles Hybrid-Electric Energy Flow vs. Airspeed Battery boost for hover and sprint
7 Challenge: Power Distribution Control Methods Battery Boosted Turbine Light Helicopter Engine power only Boost with battery Many ways power can be distributed throughout the vehicle Fundamental impact on vehicle design New design methods needed to develop and optimize power distribution Charge battery at maximum charge rate Charge battery with excess engine power
8 Challenge: Energy Management Methods Concept Vehicle Design Mission Mission Power Output and Energy Expenditure Contingency Mission Planning Recharging Complicates iterative sizing process Need to manage multiple energy sources throughout mission Need for improved hybrid-capable mission planning tools
9 Challenge: Impact of Redundant Capability Req. s Twin-Engine Helicopter HERC Heavy Hybrid Helicopter with and without Cat. A OEI Climbout Capability Payload-Range Diagrams Hybrid Battery-Boost Single Engine Uncertainty about future aviation regulations Assumptions of future regulations can heavily impact design capability
10 Challenge: Thermal Management Hybrid demonstrator produced ~5 times more waste heat Electrical components have low thermal limits (60-85 C) Minimal airflow during high-power hover
11 Challenge: Propulsion / Airframe Integration Volumetric integration Cooling ducts Cable and coolant runs Dangers of a high-voltage bus HERC Hybrid Tiltrotor Propulsion and Cooling System Integration X-57 Traction Bus