Variable-Pitch Turboprop for Emergency Windmill Power Generation

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Solution Overview

Problem

Existing turboprop engines with backup wind turbines have significant onboard mass due to the inclusion of a backup wind turbine, which is not used during normal operation, and there is a need for an alternative energy source with reduced onboard mass.

Innovation Solution

A turboprop engine configuration with a variable-pitch propeller and an electrically driven oil pump that supplies the hydraulic circuit for propeller pitch control, allowing the propeller to rotate by a windmill effect in case of failure, providing a backup power source without additional safety equipment, and reducing onboard weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a turboprop engine is designed solely for propeller-driven operation, then propeller efficiency is optimized, but the ability to provide emergency wind-turbine function is lost

Engineering Contradiction:
Improveemergency wind-turbine functionVSAvoidengine configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The turboprop engine is designed to perform multiple functions: normal propeller-driven operation and emergency wind-turbine operation. The engine includes a power conversion mechanism that can operate in both power transmission mode (driving the propeller) and power generation mode (driving the wind turbine), allowing a single engine design to serve dual purposes without requiring separate systems for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The engine incorporates a dynamically controllable power conversion mechanism with variable ratio capability. The mechanism can change its operating mode based on system needs, transitioning between acting as a power transmission device and a power generation device. This dynamic reconfigurability allows the engine to adapt to different operational requirements without permanent structural modifications.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a wind-turbine function is added to the turboprop engine, then versatility is improved, but the complexity of the power conversion mechanism increases

Engineering Contradiction:
Improvedual function capabilityVSAvoidpower conversion mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The power conversion mechanism is designed as a universal component that handles both power transmission to the propeller and power generation from the wind turbine. By integrating both functions into a single mechanism with variable ratio capability, the design avoids requiring separate dedicated mechanisms for each function, thereby limiting the increase in overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Use of energy by moving object

If the turboprop engine operates as a wind-turbine, then renewable energy utilization is improved, but the engine's primary propeller-driven function may be compromised

Engineering Contradiction:
Improverenewable energy utilizationVSAvoidpropeller-driven operation
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The engine's power conversion mechanism dynamically adjusts its operation based on system requirements. When wind conditions are favorable, the mechanism can be configured to capture wind energy and drive the turbine, providing renewable energy utilization. When wind conditions are unfavorable or propulsion is required, the mechanism switches to its primary power transmission mode, ensuring the propeller-driven function remains available as needed.

Inventive Principle:
Principle #15Dynamics

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

The configuration enables emergency power generation without additional equipment, reduces aircraft weight, and allows fine-tuning of propeller pitch over a wide speed range, ensuring power output and maintaining conventional turboprop functionality.

Implementation Method 1

a wind turbine for converting kinetic energy of moving air into mechanical energy

Methodology Applied
Scientific EffectWind power conversion: Wind Power

Implementation Method 2

a turboprop engine comprising a wind turbine... a power conversion mechanism... a propeller for converting mechanical energy into thrust

Methodology Applied
Scientific EffectMechanical energy conversion: Turbine

Data Source

PatentEP4381177B1Turboprop capable of providing an emergency propeller function and aircraft comprising such a turboprop
Publication Date: 2026.04.29 SAFRAN HELICOPTER ENGINES
  • EP4381177B1 patent drawingFigure 1
  • EP4381177B1 patent drawingFigure 2
  • EP4381177B1 patent drawingFigure 3~4

AI summary

The invention relates to a turboprop (10) comprising a propeller (12), a propeller shaft (13) carrying the propeller (12), the propeller being a variable-pitch propeller having a propeller pitch, a rotating electric machine (19) having at least a first configuration in which it is mechanically coupled to the propeller shaft (13) and at least one oil pump (21, 21B) configured to supply a hydraulic circuit for adjusting the pitch of the propeller (12). The oil pump is configured to be electrically operated. The invention further relates to an aircraft comprising such a turboprop (10) and to the methods for controlling such a turboprop (10) and such an aircraft.