Modular Counter-Rotating Propeller System Integration

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Solution Overview

Problem

Counter rotating propeller systems are complex due to integration requirements within engines, limiting their adoption and complicating variable pitch control, which has hindered engine manufacturers from leveraging their benefits.

Innovation Solution

A self-contained modular counter rotating propeller system driven by a gas turbine engine through a reduction gearbox, featuring a separate gear train for counter-rotation and a collective blade angle actuation system with a single actuator to adjust both sets of propeller blades, allowing for independent rotation and pitch control without modifying existing engine or gearbox configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If counter rotating propeller systems are highly integrated within the engine, then the propeller system can be compact, but the device complexity and integration requirements increase significantly

Engineering Contradiction:
Improvepropeller system volumeVSAvoidintegration complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The propeller system is divided into separate modular components: a first counter-rotating propeller assembly and a second counter-rotating propeller assembly, each with independent hubs, blades, and drive mechanisms. This segmentation allows each module to be designed and manufactured independently, reducing overall integration complexity while maintaining compactness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The counter-rotating propeller mechanism is extracted from the traditional engine integration and positioned as a separate system driven by a single shaft through a reduction gearbox. This extraction eliminates the need for complex internal integration within the engine while maintaining the counter-rotating function, thereby reducing device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If multiple actuators are used to control blade angle of both propeller blade sets, then independent control is achieved, but the device complexity and control structure increase

Engineering Contradiction:
Improveblade angle controlVSAvoidcontrol structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

A single actuator is designed to perform multiple functions by controlling the blade angle of both the first and second propeller blade sets through a translation mechanism. This universal actuator eliminates the need for separate actuators for each propeller set, reducing control structure complexity while maintaining independent control capability.

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

Solution Approach 2:

A translation mechanism serves as an intermediary between the single actuator and the two propeller blade sets. This intermediary converts the actuator's motion into appropriate blade angle adjustments for both propeller sets, enabling controlled operation without requiring multiple actuators.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the propeller system is modified to enable counter-rotation, then propulsion efficiency improves, but the ease of manufacture and integration with existing engines decreases

Engineering Contradiction:
Improvepropulsion efficiencyVSAvoidintegration ease
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The system uses segmented propeller assemblies that can be manufactured as separate modules and then assembled. Each assembly includes its own hub, blades, and drive components, allowing for standardized manufacturing processes and simplifying integration with existing engines through modular installation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The counter-rotating propeller mechanism is extracted as a separate system that interfaces with the existing engine through a single shaft connection and reduction gearbox. This extraction approach maintains propulsion efficiency while avoiding the need to modify existing engine components, thereby improving ease of manufacture and integration.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution simplifies the integration and control of counter rotating propeller systems, enabling efficient operation within existing engine platforms with reduced complexity and no need for additional modifications, allowing for optimized performance and flexibility in torque distribution between propeller blades.

Implementation Method 1

A gear train housed separate from the reduction gearbox provides the counter-rotation of a first and second pluralities of propeller blades

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

The example collective blade control system includes a single actuator to control blade angle of both the first and second plurality of propeller blades

Methodology Applied
Scientific EffectMechanical actuation: Mechanical Advantage

Implementation Method 3

A translation mechanism is provided for communicating blade angle changes between the first and second plurality of propeller blades

Methodology Applied
Scientific EffectMechanical transmission: Mechanical Advantage

Data Source

PatentEP2557033B1Modular counter rotating propeller system
Publication Date: 2019.10.02 HAMILTON SUNDSTRAND CORP
  • EP2557033B1 patent drawingFigure 1
  • EP2557033B1 patent drawingFigure 2~3
  • EP2557033B1 patent drawingFigure 4~5

AI summary

A self-contained counter rotating turbo prop system (14) is driven by a gas turbine engine (10) through a reduction gearbox (12). A gear train housed separate from the reduction gearbox (12) provides the counter-rotation of a first and second pluralities of propeller blades (18,20). The entire counter-rotating propeller system (14) is disposed within cowlings (16A,16B) and is separate from the gas turbine engine (10) and reduction gearbox (12). The counter rotating propeller system (14) includes a collective blade angle actuation system (55) that provides for adjustment of blade angle of both the first and second plurality of propeller blades (18,20) with a single actuator.