Dual-Motor Aircraft Propulsion With Overrunning Clutch Decoupling

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Solution Overview

Problem

Existing electric powerplant systems for aircraft propulsion systems lack efficient mechanisms for managing power distribution and redundancy, leading to increased rotational friction and drag during single motor operation and potential electrical issues in the event of a motor fault.

Innovation Solution

A propulsion system with dual electric motors and overrunning clutches that selectively couple and decouple from the drivetrain based on power status, allowing for efficient power distribution and automatic decoupling of inactive motors to reduce friction and drag, and incorporating a common housing structure for shared lubrication and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If dual electric motors are used for aircraft propulsion, then power output and redundancy are improved, but rotational friction and drag increase during single motor operation

Engineering Contradiction:
Improvepower outputVSAvoidrotational friction and drag
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the inactive motor from the power transmission system by using overrunning clutches to disengage the second motor when only the first motor is operating. This removes the harmful rotational friction and drag that would otherwise occur from the inactive motor's drive train components, while preserving the ability to use both motors when needed for increased power output.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If motors remain coupled to drivetrain during inactive operation, then power distribution is simplified, but electrical hazards and energy loss increase

Engineering Contradiction:
Improvepower distribution mechanismVSAvoidelectrical safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The overrunning clutch acts as an intermediary mechanism between the motor and drivetrain. It allows the motor to be selectively coupled or decoupled from the power transmission system based on operational status. This mediator protects the system by automatically isolating inactive motors from the drivetrain, preventing electrical hazards and energy loss while maintaining a relatively simple control architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-generated harmful factors

If overrunning clutches are used to decouple inactive motors, then friction and drag are reduced, but device complexity increases

Engineering Contradiction:
Improverotational frictionVSAvoidclutch mechanism
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The overrunning clutch is designed as a passively actuated mechanism that automatically engages and disengages based on the rotational speed relationship between the motor and drivetrain. When the motor is inactive or running slower than the drivetrain, the clutch automatically slips or disengages without requiring active control. This self-regulating behavior reduces friction and drag while minimizing the complexity of control systems needed to manage the dual-motor configuration.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances power efficiency and reduces drag and electrical hazards by enabling seamless power distribution and automatic decoupling of inactive motors, improving operational reliability and reducing friction during single motor operation.

Implementation Method 1

The first overrunning clutch is configured to selectively couple the first electric motor to the drivetrain. The second overrunning clutch is configured to selectively couple the second electric motor to the drivetrain.

Methodology Applied
Scientific EffectOverrunning clutch mechanism: Ratchet

Implementation Method 2

The first electric motor is configured to drive rotation of the propulsor rotor through the first overrunning clutch and the drivetrain. The second electric motor is configured to drive the rotation of the propulsor rotor through the second overrunning clutch and the drivetrain.

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP4703268A1Clutched electric powerplant for aircraft propulsion system
Publication Date: 2026.03.04 PRATT & WHITNEY CANADA CORP
  • EP4703268A1 patent drawingFigure 1
  • EP4703268A1 patent drawingFigure 2A~2B
  • EP4703268A1 patent drawingFigure 3

AI summary

A propulsion system (20) is provided for an aircraft. This propulsion system (20) includes a propulsor rotor (22), a drivetrain (24), a first power unit (38A) and a second power unit (38B). The drivetrain (24) is coupled to the propulsor rotor (22). The first power unit (38A) includes a first overrunning clutch (44A) and a first electric motor (42A). The first overrunning clutch (44A) is configured to selectively couple the first electric motor (42A) to the drivetrain (24). The first electric motor (42A) is configured to drive rotation of the propulsor rotor (22) through the first overrunning clutch (44A) and the drivetrain (24). The second power unit (38B) includes a second overrunning clutch (44B) and a second electric motor (42B). The second overrunning clutch (44B) is configured to selectively couple the second electric motor (42B) to the drivetrain (24). The second electric motor (42B) is configured to drive the rotation of the propulsor rotor (22) through the second overrunning clutch (44B) and the drivetrain (24).