Description: Hybrid-electric propulsion is becoming widely accepted as a potential disruptive technology for aircraft that can provide significant reduction in fuel consumption as well as many other benefits. The majority of the analysis tools that exist today, however, do not harness the capability to analyze these unique systems, especially in the rotorcraft realm. The Phase I effort focused mainly on the development of the PANTHER tool in preparing it for modeling hybrid and all-electric rotorcraft. The tool was then exercised by modeling a handful of propulsion architectures. The goal of the proposed Phase II effort is to further improve upon the strengths of the PANTHER code that was developed, and then utilize this tool to further explore the hybrid-electric rotorcraft design space. Given the goals of the Revolutionary Vertical Lift Technology Project (RVLT), the PANTHER tool must be further expanded to enable the sizing and performance analysis of unique rotorcraft configurations with propulsion system designs unseen in the vertical lift realm. The tool will be expanded with modules for fuel cells and flywheels along with improved engine modules, physics-based motor and drive models, and a new capability to model complete missions. The thermal management aspect will also be addressed with modules for radiators, cooling ducts, fluids, and pumps. With the capability of PANTHER vastly enhanced, numerous trade studies will then be conducted that attempt to explore a large portion of the rotorcraft trade space made possible by hybrid-electric propulsion systems. These trades will aim to answer many of the questions that have arisen in the community about hybrid-electric rotorcraft. Using the results and lessons learned from these studies, and accommodating the goals of NASA and the RVLT project, a detailed conceptual design will be performed on a notional hybrid-electric rotorcraft demonstrator.

Benefits: The potential NASA applications for this proposed effort will focus on delivering a tool that fits within a larger MDAO framework for hybrid electric aircraft design synthesis with a highly integrated thermal management system design and analysis tool, benefitting multiple NRA projects, and other direct NASA efforts, both internal and external. Several nuances native to the turbo-electric or hybrid electric distributed propulsion are electric component weight and structure, power transmission networks, and thermal management systems, collectively requiring a tool such as the one proposed for initial aircraft design synthesis. These new hurdles have not been addressed in previous textbook methods or efforts, but play a significant role in determining the feasibility of these new aircraft configurations. One of the major benefits to a decoupled energy management system using distributed propulsion is the freedom in placing the propulsors. Each configuration will inherently have vastly different structural and cooling considerations.

A commercial application for top-level distributed propulsion sizing tool would be very attractive, as the industry is pressing toward hybrid-electric distributed propulsion (HEDP) concepts as new technologies for electric components and batteries develop. This product will leverage its ability to customize the propulsion system architecture and operation, and it will offer detailed analysis of thermal management system design and performance. A potential Phase III effort could pair the sizing and weights tool with aerodynamic analysis, terminal area operation analysis, and mission analysis tools to provide designers with a very useful hybrid electric aircraft design and analysis suite. AFRL would benefit as they are conducting in-house studies and supporting ESAero in other related areas. IARPA and the FAA will also benefit, as the tool will be distributed within the government FOUO. ESAero has identified the government and industry partners to develop this type of technology both near term (Boeing, General Electric, Lockheed Martin) and long term (NASA, AFRL, IARPA etc.).