Helicopter Rotor Control System Hydraulic Actuation

Solution Overview

Problem

Conventional rotor control systems in dual or counter-rotating helicopter systems are hindered by the weight and packaging challenges of heavy, large-diameter control rods used in the upper rotor control system, which are prone to buckling forces and difficult to integrate within the rotor shaft.

Innovation Solution

A rotor control system utilizing a swashplate assembly with hydraulic actuators that transmit control signals directly to the rotor blades, eliminating the need for conventional control rods and reducing weight and stress on the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If heavy, large-diameter control rods are used in the upper rotor control system, then resistance to buckling forces is improved, but weight and packaging difficulty increase

Engineering Contradiction:

Improveresistance to buckling forcesVSAvoidweight of control rods

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent replaces the conventional mechanical control rod system with a hydraulic actuator system. The hydraulic actuators use fluid pressure to transmit control forces, eliminating the need for heavy mechanical rods while maintaining the required strength and buckling resistance through hydraulic pressure rather than structural mass.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs hydraulic actuators to transmit control signals and forces from the swashplate assembly to the rotor blades. This hydraulic system uses incompressible fluid to transmit forces efficiently, providing the necessary strength without requiring heavy mechanical components, thus resolving the contradiction between strength and weight.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Strength

If heavy, large-diameter control rods are used in the upper rotor control system, then resistance to buckling forces is improved, but packaging within rotor shaft becomes difficult

Engineering Contradiction:

Improveresistance to buckling forcesVSAvoidpackaging space within rotor shaft

Core Design Contradiction:

StrengthVSVolume of moving object

Solution Approach 1:

The patent replaces the mechanical control rod system with a hydraulic actuator system. The hydraulic actuators use fluid pressure to transmit control forces, eliminating the need for heavy mechanical rods while maintaining the required strength and buckling resistance through hydraulic pressure rather than structural mass.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The hydraulic fluid acts as an intermediary medium to transmit forces from the swashplate assembly to the rotor blades. This fluid intermediary allows force transmission without requiring direct mechanical connection through heavy rods, enabling compact packaging within the rotor shaft while maintaining structural integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If conventional control rods are used, then structural simplicity is maintained, but weight and stress on the system increase

Engineering Contradiction:

Improvestructural simplicityVSAvoidweight of control system

Core Design Contradiction:

Device complexityVSWeight of moving object

Solution Approach 1:

The patent replaces the conventional mechanical control rod system with a hydraulic actuator system. The hydraulic actuators use fluid pressure to transmit control forces, eliminating the need for heavy mechanical rods while maintaining the required strength and buckling resistance through hydraulic pressure rather than structural mass.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs hydraulic actuators to transmit control signals and forces from the swashplate assembly to the rotor blades. This hydraulic system uses incompressible fluid to transmit forces efficiently, providing the necessary strength without requiring heavy mechanical components, thus resolving the contradiction between strength and weight.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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

This solution enhances the control system's resistance to internal forces and weight, improving the efficiency and packaging of the upper rotor control system by using hydraulic actuators to adjust rotor blade pitch, thereby reducing the system's overall weight and stress.

Implementation Method 1

at least one hydraulic actuator member is operatively coupled to the control horn and at least one hydraulic actuator element is operatively coupled to the swashplate assembly and the at least one hydraulic actuator member. The at least one hydraulic actuator member transmits control signals from the swashplate assembly to the one of the plurality of rotor blades

Methodology Applied

Scientific EffectHydraulic actuation: Hydraulic Press

Data Source

PatentUS8858179B2Helicopter rotor control system

Publication Date: 2014.10.14 SIKORSKY AIRCRAFT CORP

AI summary

A rotor control system operatively linked to a plurality of rotor blades includes a swashplate assembly having a stationary member and a rotating member. A blade attachment member is operatively connected to the plurality of rotor blades and a control horn is operatively connected to the blade attachment member and one of the plurality of rotor blades. At least one hydraulic actuator member is operatively coupled to the control horn and at least one hydraulic actuator element is operatively coupled to the swashplate assembly and the at least one hydraulic actuator member. The at least one hydraulic actuator member transmits control signals from the swashplate assembly to the one of the plurality of rotor blades through the at least one hydraulic actuator member.