Aircraft Nacelle Thrust Reverser Flap Actuation
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Solution Overview
Problem
Existing aircraft engine nacelle designs with thrust reverser systems suffer from aerodynamic losses and inadequate noise reduction due to complex flap mechanisms and numerous connections, which limit the application of acoustic treatments and result in deformation issues during adjustment.
Innovation Solution
A nacelle design featuring a fixed front part and a moving rear part with flaps that deploy automatically under elastic force, eliminating the need for hydraulic, electrical, or pneumatic actuators, and incorporating a single connection zone for improved aerodynamics and noise reduction, with internal and external flaps that divert flow using a spring-activated mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complex flap mechanisms with multiple connections are used to control thrust reverser flaps, then the flaps can be positioned accurately, but aerodynamic losses increase and noise reduction treatment is limited
Solution Approach 1:
The patent removes the complex rod connection mechanisms and remote actuators from the system. Flaps are now directly hinged to the moving rear part of the nacelle, eliminating intermediate transmission components. This extraction of unnecessary elements reduces aerodynamic interference while maintaining positioning accuracy through direct mechanical coupling.
Solution Approach 2:
The nacelle is divided into a fixed front part and a moving rear part that slides longitudinally. The flaps are segmented and individually hinged to the moving part, allowing independent control while reducing overall system complexity. This segmentation enables simplified actuation through direct connection to the moving nacelle section.
2Ease of operation
If numerous connections and obstacles are present in the nacelle structure, then flap control is achieved, but aerodynamic performance deteriorates
Solution Approach 1:
The patent eliminates rods, remote actuators, and multiple connection points from the nacelle structure. Flaps are directly hinged to the moving rear part, removing intermediate mechanical elements that create aerodynamic drag and interference. This results in cleaner airflow paths while maintaining operational control through the sliding mechanism.
3Reliability
If seals are fitted at connection zones to prevent flow escape, then thrust reverser effectiveness is maintained, but acoustic treatment capability is reduced
Solution Approach 1:
The patent removes the need for seals at connection zones by eliminating remote connections entirely. The single integrated hinge connection between flaps and the moving nacelle part requires no sealing, creating a large continuous surface area suitable for acoustic treatment application while maintaining thrust reverser functionality.
4Manufacturing precision
If remote actuator control systems are used to deploy flaps, then precise flap positioning is achieved, but device complexity and weight increase
Solution Approach 1:
The patent removes remote actuator control systems, hydraulic lines, and complex transmission mechanisms. Flap positioning is achieved through direct mechanical coupling to the moving rear part of the nacelle, which slides longitudinally to deploy or retract flaps. This eliminates multiple components while maintaining positioning precision through the direct sliding-flap connection.
Solution Approach 2:
The actuation function is merged with the nacelle's longitudinal sliding motion. The moving rear part simultaneously performs the functions of structural support, flap hinge mounting, and actuation mechanism, eliminating the need for separate remote actuators and reducing overall system complexity.
5Stability of the object's composition
If multiple connection zones are present between fixed and moving parts, then structural stability is maintained, but aerodynamic losses and noise increase
Solution Approach 1:
The patent merges all connection functions into a single integrated hinge connection between the flaps and the moving rear part. This single connection zone maintains structural stability for flap support while minimizing aerodynamic interference compared to multiple distributed connection points. The moving nacelle part itself provides structural stability during sliding motion.
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 enhances aerodynamic performance and acoustic qualities by reducing protrusions, allowing for effective noise reduction and simplified operation, while increasing safety and reducing weight by eliminating the need for remote actuation systems.
Implementation Method 1
an elastic force is applied on the flaps towards a deployed position, so that when the moving part uncovers the flaps, the latter are automatically deployed
Implementation Method 2
a spring-activated mechanism
Data Source
AI summary
Aircraft nacelle which includes a cowl with a longitudinal axis, an engine housed in the cowl, an annular channel surrounding the engine and designed to receive a secondary flow, wherein the cowl includes a fixed part and a moving part which slides along the longitudinal axis to define a radial opening between the moving and fixed parts, a thrust reverser system which includes internal flaps mounted so that they rotate and which are designed to block the annular channel, at least partially, in the deployed position, where the moving part of the cowl includes a radial housing to receive the internal flaps in the at-rest position and where a system of applying an elastic force on each flap towards deployment is provided. Thus control over the position of the internal flaps is obtained directly by sliding the moving part.