Release Date
August 23rd, 2023
Open Date
September 20th, 2023
Due Date(s)
October 18th, 2023
Close Date
October 18th, 2023
Topic No.


Hybrid Turbo-Electric Propulsion Design and Optimization


Department of DefenseN/A


Type: SBIRPhase: BOTHYear: 2023


The Department of Defense (DoD) is seeking proposals for the topic of "Hybrid Turbo-Electric Propulsion Design and Optimization" as part of the SBIR program. The Air Force branch is specifically interested in exploring the feasibility of hybrid turbine propulsion architectures to enhance the capabilities of advanced VTOL and CTOL aircraft. The goal is to develop a prototype that demonstrates improved mission performance in critical flight phases compared to conventional turbines. The research will involve trade space analysis, performance data collection, and collaboration with AFWERX Prime and other DoD stakeholders. The Phase I feasibility study should identify current designs, limiting factors, and potential solutions, while Phase II will focus on maturing the chosen design through prototyping and testing. The technology developed in this project has potential applications in both the commercial sector and within the DAF ecosystem, supporting the Agility Prime efforts. The solicitation is closed, and more details can be found on the DoD SBIR 23.3 BAA page on


OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Renewable Energy Generation and Storage;Trusted AI and Autonomy


OBJECTIVE: Conventional turbines and hybrid powertrains have been seen to limit the operational parameters of advanced VTOL and CTOL aircraft and there is strong evidence to believe novel hybrid turbine propulsion architecture can provide enhanced capabilities to provide expanded mission sets beyond what is currently possible in the Air Force.  The technology space for hybrid turbine propulsion is growing and the Air Force would like to better understand the feasibility of existing models to meet or exceed current industry standards for turbines, conduct trade space analysis to increase performance characteristics, and develop a prototype to demonstrate performance.  The purpose of this topic is to demonstrate that a hybrid turbine propulsion architecture can achieve greater mission performance in key critical phases of flight over conventional turbines. The effort will feed requirements generation and future concept evaluation by AFWERX Prime for electrified aircraft by proving the feasibility, maturity, and mission impact of hybrid turbine propulsion architectures while providing mission relevant capability such as enabling vertical take-off of otherwise overly complicated configurations, maintaining power at high altitude or boosting power for dash phases and exporting power for payloads during cruise. The Agility Prime program has seen the benefit of hybrid powertrains that utilize electric motors for propulsion and hypothesizes that this benefit not only transfers to turbines but will be relevant to a number of existing and future aircraft.


DESCRIPTION: Conventional turbines have typical performance designed towards a peak thrust required for takeoff and an efficient cruise for longer range. AFWERX Prime is interested in the performance enhancement potential of hybrid turbine propulsion architectures which directly link electric machines to turbomachinery input/output shafts. These architectures of “turbo-electric” machines are then able to leverage multiple energy sources (electrical and chemical) and aerodynamic work outputs (fan blades) to produce thrust in novel combinations which are better optimized for various phases of flight. This could be leveraged to better optimize for specific mission profiles such as Vertical Take off and Landing, high altitude loft, fuel efficient cruise, high speed dash, or payload power draw.  The architectures are not limited in sizing, maturity, or architecture at this stage; however, it is necessary to investigate and produce a report on their design to achieve greater performance than comparable conventional turbines in one or more of the key mission areas above.  A key metric for this topic is to collect and analyze performance data from existing physical prototypes (small scale turbo-electric machines) to inform the design trade space of future systems.    It is expected that a company will work collaboratively with AFWERX and other invested DoD stakeholders throughout the full period of performance to inform the tradespace and evaluate potentials.   Companies should be mindful during their analysis and design efforts, to identify significant changes in required maintenance and or operational burden and cost.  While there is a need to enhance performance in the areas mentioned, a cost benefit balance to the overall system should be maintained.  Of note, as a SBIR Topic it is required that proposals are received by SBCs, but companies are allowed to collaborate with academia and partners if need be and AFWERX Prime is interested in all relationship dynamics as long as they adhere to SBIR regulations.


PHASE I: The Phase I effort should consist of a feasibility study and analysis showing that a company’s current technology can, currently or with further innovation, exceed the performance characteristics of conventional turbines to achieve one or more of the following use case/mission parameters:  1. Increased endurance 2. VTOL capability 3. Electrical power output to payloads 4. Increased Altitude Ceiling 5. Increased Maximum Speed  The feasibility study is expected to be fed from analysis of current models or prototypes and should include, but not be limited to the following content:  a) Tradespace analysis conducted by your team to converge on current design(s) b) Limiting factors to reach maximum performance and potential to overcome c) Technical recommendation or prioritization of alternative solutions  Deviations in use case and characteristic improvements not mentioned herein may be explored with coordination with AFWERX Prime and its partner Stakeholders.  Success criteria for Phase I is an analysis of trade space and a recommended path forward that describes the design’s technical feasibility and a description of work required.


PHASE II: Phase II should pick up where the Phase I left off and will focus on the maturation of a Customer approved design. It is expected that, based on the Phase I results one design or development aspect will be chosen for Phase II development and maturation. The effort should focus on refining the astechnology such that the performance characteristics proposed in Phase I can be verified through prototyping or demonstration. Phase II should result in a demonstration or prototype test and report that validates the capabilities proposed out of Phase I.  Additional phase II work efforts include, but are not limited to: Improve and refine the digital models developed in phase 1 throughout prototype integration and testing process, explore supplier options for hybrid power and thermal management architectures and key components to identify key technology gaps, and quantity technology metric goals, required to enable significant capability improvements.


PHASE III DUAL USE APPLICATIONS: Phase III potential exists both in the commercial sector and within the DAF ecosystem. This work will be transitioned and scaled to support Agility Prime efforts. There are opportunities to flight demo and test within the Prime program construct while also exploring and extending the use cases to additional AF interested parties.




KEYWORDS: electric; hybrid; turbine; turbo; turbofan; turbojet; turboshaft; turboprop; parallel hybrid; series; electric motor; propulsion