A key goal of NASA’s aeronautics research is to help the aircraft industry transition to low-carbon propulsion. Many potential power architectures for electric propulsion have been proposed, and design considerations for turbo-electric distributed propulsion have been studied. However, few mid- to full-scale testbeds have been built to validate these different architectures.

The 31-foot LEAPTech wing was tested on the back of a modified flatbed truck at speeds simulating takeoff and landing for validation of aerodynamic and propulsive performance.

Now, thanks to an important NASA research effort, the hardware testbed required to enable informed decision-making is forthcoming. The Hybrid Electric Integrated System Testbed (HEIST) will study the major aspects of combined gas-electric distributed propulsion.

The HEIST Ironbird is centered on a research wing used in the Leading-Edge Asynchronous Propeller Technology (LEAPTech) Project. LEAPTech was designed with 18 independent batterypowered electric motors mounted on a 31-foot carbon composite wing. After testing the LEAPTech wing on the back of a modified flatbed truck at speeds simulating takeoff and landing for validation of aerodynamic and propulsive performance, researchers began constructing the HEIST Ironbird to integrate the wing with a configurable piloted simulation system.

The 200-kW testbed will accommodate representative hybrid gas-electric aircraft configurations as well as missions for flight controls, propulsive, and power transfer research. It will also be designed to scale up to a 2-MW system and accommodate a flight research computer. Dynamometers will simulate aerodynamic loading.

With its combination of representative hardware and piloted simulations, the HEIST Ironbird will investigate flight control algorithms, power management, and transition issues of hybrid electric propulsion. It will enable users to test different mission profiles, control systems, power configurations, and failure modes in a hardware-in-the-loop simulated flight environment. Various bus configurations will be tested to determine weight, size, electromagnetic interference (EMI), and thermal and energy transmission efficiency.

Researchers will use the information gleaned from HEIST Ironbird to develop new technologies and additional capabilities that will allow them to assess the flight readiness — and safely carry out testing — of hybrid electric/ distributed electric flight. Such developments will include:

  • Flight test vehicle design
  • Evaluation of concept aircraft
  • Flight test support
  • Flight simulations

The HEIST Ironbird research effort will enable the design of more advanced electric propulsion system testbeds. By providing informed assessments of key technology drivers and methodologies, HEIST will help NASA shape the upcoming low-carbon X-plane.

This work was done by Kurt Kloesel, Yohan Lin, Starr Ginn, Sean Clarke, Kurt Papathakis, and Jacob Ediger of Armstrong Flight Research Center. NASA is seeking partners to further develop this technology through joint cooperative research and development. For more information about this technology and to explore opportunities, please contact NASA Armstrong Technology Transfer Office at 661-276-3368 or by e-mail at This email address is being protected from spambots. You need JavaScript enabled to view it.. DRC-016-006


NASA Tech Briefs Magazine

This article first appeared in the October, 2016 issue of NASA Tech Briefs Magazine.

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