Hybrid-Electric Powertrain Testing for Aircraft Propulsion

Collins Aerospace and Pratt & Whitney have initiated subsystem-level testing of a hybrid-electric aircraft powertrain under the European Clean Aviation SWITCH programme, targeting improved propulsion efficiency for short- and medium-range aircraft.

Context of the Cooperation
The SWITCH project brings together multiple aerospace manufacturers and research organisations, including Collins Aerospace, Pratt & Whitney, MTU Aero Engines, Airbus and GKN Aerospace. The cooperation addresses the challenge of reducing fuel consumption and emissions in commercial aviation through hybrid-electric propulsion architectures.

Collins Aerospace contributes expertise in electric power systems, while Pratt & Whitney leads integration into a geared turbofan (GTF) engine demonstrator. GKN Aerospace and European partners provide electrical interconnection and supporting subsystems. The scale and complexity of integrating megawatt-class electrical systems into aircraft propulsion require coordinated development across multiple specialised domains.

Technical Solution and Responsibilities
The system under development is a hybrid-electric powertrain combining conventional turbofan propulsion with electrically driven components.Key subsystems include:

Collins Aerospace designed and manufactured the electric motor generators and control systems at its UK facility, while also leading subsystem validation. Power distribution components, including solid-state power controllers, were developed in Germany. GKN Aerospace supplied the high-voltage wiring system.

The architecture operates by supplementing mechanical engine power with electrical energy during specific flight phases, enabling optimized load distribution and improved overall engine efficiency. The system relies on high-voltage DC distribution and advanced control algorithms to manage power flow between generators and propulsion elements.

Deployment and Implementation
Initial validation is being conducted at “The Grid,” Collins Aerospace’s electric power systems integration laboratory in Rockford, Illinois. This facility enables controlled testing of integrated subsystems under representative electrical loads and operating conditions.

The current phase focuses on validating the interaction between motor generators, controllers and distribution systems. Following subsystem verification, the components will be integrated into a full-scale hybrid-electric Pratt & Whitney GTF engine demonstrator.

The project also involves distributed development across European sites, requiring standardised interfaces and compliance with aerospace electrical system requirements, including high-voltage safety and redundancy considerations.

Applications and Use Cases
The primary application is commercial aviation propulsion, particularly for next-generation single-aisle aircraft. Hybrid-electric systems are intended to:

These developments align with broader trends in digital infrastructure and electrification within aerospace systems.

Results and Expected Impact
Testing focuses on validating megawatt-class electrical components under realistic operating conditions, a prerequisite for scaling hybrid-electric propulsion. By enabling distributed power management across the propulsion system, the architecture can reduce peak engine loads and improve thermodynamic efficiency.

Although quantitative performance data has not been disclosed, the integration of electrical subsystems into a turbofan engine demonstrator represents a key step toward certifiable hybrid-electric propulsion systems for regional and short- to medium-range aircraft.

Edited by an industrial journalist, Sucithra Mani, with AI assistance.

www.ti.com