Tiltrotor Proprotor Door Mechanism for Vibration Control
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Solution Overview
Problem
Tiltrotor aircraft experience unwanted vibrations and aerodynamic disruptions due to the rotation of the proprotor gearbox system during mode transitions, which affects the aircraft's performance and efficiency.
Innovation Solution
A door mechanism is hingedly coupled to the proprotor housing and nacelle, rotating between horizontal and non-horizontal orientations to cover recesses and maintain an aerodynamic profile, using a roller track assembly and pivot mechanisms to manage movement and reduce vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the proprotor gearbox system rotates during mode transitions, then the aircraft can convert between vertical and forward flight modes, but unwanted vibrations are transmitted to other aircraft components
Solution Approach 1:
The door mechanism extracts and isolates the harmful vibrations generated during proprotor rotation by providing a separate structural element that can move independently to accommodate the rotating proprotor while maintaining a stable aerodynamic profile for the nacelle
Solution Approach 2:
The door is divided into multiple segments or panels that can move independently through hinge joints, allowing each segment to accommodate the rotating proprotor while collectively maintaining the overall aerodynamic profile of the nacelle
2Adaptability or versatility
If the proprotor gearbox system rotates during mode transitions, then the aircraft can convert between vertical and forward flight modes, but aerodynamic profile is interrupted behind the rotation axis
Solution Approach 1:
The door mechanism transforms the static aerodynamic profile requirement into a dynamic solution where the door panels move and adjust their positions in response to proprotor rotation, maintaining an aerodynamic profile during both horizontal and non-horizontal orientations
Solution Approach 2:
Different portions of the door structure have different properties - the hinge joints provide flexibility and movement capability while the door panels maintain rigid aerodynamic surfaces, creating local variations in structural quality to satisfy both movement and aerodynamic requirements
Data Source
AI summary
An aircraft including a nacelle configured as a housing for an engine and disposed at a fixed location relative a wing member; a proprotor housing coupled to the nacelle, the proprotor housing configured to selectively rotate between a horizontal orientation and a non-horizontal orientation; a door hingedly coupled to the proprotor housing by a first hinge joint and hingedly coupled to the nacelle by a second hinge joint. An aspect includes an aircraft with a proprotor coupled to a wing member, the proprotor comprising a forward portion and an aft portion; wherein the forward portion is configured to selectively pivot between a horizontal orientation and a non-horizontal orientation about a conversion axis C; and wherein when the forward portion is in a non-horizontal orientation, the aft portion is in a horizonal orientation.