Aircraft Nacelle Variable Nozzle Rack and Pinion Actuation

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Solution Overview

Problem

Existing aircraft engine nacelles with thrust reversal systems are heavy due to the use of specific jacks and locking mechanisms required for independent actuation of the thrust reverser cowl and outlet nozzle.

Innovation Solution

A nacelle design utilizing a rack and pinion system for independent actuation of the thrust reverser cowl and outlet nozzle, with a motor pinion and rack integral with the nozzle, allowing for simpler, less bulky, and lighter operation compared to prior art systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If specific jacks and locking mechanisms are used for independent actuation of thrust reverser cowl and outlet nozzle, then independent actuation capability is achieved, but weight increases

Engineering Contradiction:

Improveindependent actuation capabilityVSAvoidnacelle weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The actuation system is segmented into two independent subsystems: one for the thrust reverser cowl (using jacks) and one for the outlet nozzle (using rack and pinion). This allows each subsystem to be optimized independently, reducing overall weight while maintaining independent actuation capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The heavy locking mechanisms and complex jack systems are replaced with a rack and pinion mechanism for nozzle actuation. This mechanical substitution reduces weight while maintaining the required independent actuation functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If specific jacks and locking mechanisms are used for independent actuation of thrust reverser cowl and outlet nozzle, then independent actuation capability is achieved, but device complexity increases

Engineering Contradiction:

Improveindependent actuation capabilityVSAvoidactuation system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The actuation system is divided into separate independent subsystems, each with its own actuation mechanism. This segmentation simplifies the overall system architecture by avoiding the need for a single complex mechanism to control both components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Complex locking mechanisms are replaced with the simpler rack and pinion mechanism, reducing overall system complexity while maintaining independent actuation capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If specific jacks and locking mechanisms are used for independent actuation of thrust reverser cowl and outlet nozzle, then independent actuation capability is achieved, but bulk increases

Engineering Contradiction:

Improveindependent actuation capabilityVSAvoidnacelle volume

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The bulky locking mechanisms and large jack systems are replaced with a more compact rack and pinion mechanism, reducing the overall volume occupied by the actuation system while maintaining full independent actuation capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables independent actuation of the exhaust nozzle with respect to the thrust reverser cowl using a rack and pinion system, reducing weight and bulk while maintaining efficient operation across different flight phases.

Implementation Method 1

at least one rack for actuating said exhaust nozzle, integral with this nozzle and meshing with said motor pinion when said thrust reverser cowl is in the direct jet position

Methodology Applied

Scientific EffectRack and pinion: Rack and Pinion

Data Source

PatentEP2561208B1Aircraft engine nacelle with variable nozzle section

Publication Date: 2015.05.13 AIRCELLE SA

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AI summary

This nacelle for an aircraft engine comprises a thrust reverser cowling (11) slidably mounted between a direct-jet position and reverse-jet position, an outlet jet pipe nozzle (13) of variable cross section positioned in the downstream continuation of this reverser cowling (11), and means for respectively actuating this cowling (11) and this nozzle (13). Said jet pipe nozzle (13) is slidably mounted on said thrust reverser cowling (11) and said thrust reversal means comprise: at least one cylinder actuator (45) for actuating said thrust reverser cowling (11); at least one driving pinion (37) mounted to rotate on the fixed structure of said nacelle; and at least one rack (35) for actuating said jet pipe nozzle (13) and secured to this jet pipe nozzle (13) and meshing with said driving pinion (37) when said thrust reverser cowling (11) is in the direct-jet position, and escaping from this pinion when said reverser cowling (11) is in the reverse-jet position.