Elastomeric Joint Rotor Blade Twist Control
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Solution Overview
Problem
Tiltrotor aircraft blades face challenges in dynamically adjusting twist to accommodate various atmospheric conditions, leading to potential jamming in icy conditions and reduced control system reliability.
Innovation Solution
A rotor blade design featuring an elastomeric joint between the root portion and a movable member, allowing for shear deformation to adjust twist during different flight modes, with an actuating system controlling the movable member's position to optimize twist distribution for helicopter and airplane modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a metal joint is used in the rotor blade actuating system, then the blade can be controlled to adjust twist for different flight modes, but the joint can jam in icy conditions causing increased weight and control system malfunction
Solution Approach 1:
The patent replaces the traditional metal mechanical joint with an elastomeric joint that uses elastic deformation to achieve the same actuation function. The elastomeric material allows the blade to change twist angle through elastic compliance rather than rigid mechanical connections, eliminating jamming in icy conditions while maintaining control authority.
Solution Approach 2:
The patent changes the material parameter from rigid metal to flexible elastomer, allowing the joint to deform elastically under actuation loads. This parameter change enables the system to maintain functionality across a wider range of environmental conditions, particularly preventing ice-related jamming while achieving the required twist adjustment range.
2Productivity
If the rotor blade is designed with variable twist capability, then aerodynamic performance is improved for both helicopter and airplane modes, but the device complexity increases with additional actuators and joints
Solution Approach 1:
The patent merges the actuation function into the blade structure itself by using the elastomeric joint as an integral part of the blade assembly rather than a separate mechanical component. This integration reduces the number of discrete parts and simplifies the overall actuating system while maintaining the variable twist capability needed for optimized aerodynamic performance in both helicopter and airplane modes.
Solution Approach 2:
The elastomeric joint serves multiple functions simultaneously: it acts as a structural connector, an actuation mechanism, and a twist adjustment device. This multi-functionality reduces the need for separate components for each function, thereby reducing overall system complexity while achieving the desired aerodynamic performance across different flight modes.
3Ease of manufacture
If a rigid blade structure is used, then manufacturing and structural integrity are simplified, but the blade cannot dynamically adjust twist to accommodate various atmospheric conditions
Solution Approach 1:
The patent segments the blade into rigid and flexible portions, with the elastomeric joint providing the necessary flexibility for twist adjustment while the majority of the blade structure remains rigid for manufacturing simplicity and structural integrity. This segmentation allows the blade to maintain ease of manufacture while gaining dynamic adaptability.
Solution Approach 2:
The patent applies local flexibility only at the joint region where twist adjustment is needed, while the rest of the blade maintains rigid properties for structural strength and manufacturing simplicity. This localized application of elastomeric material provides the necessary adaptability without compromising the overall structural integrity or manufacturing ease of the blade.
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 elastomeric joint prevents jamming and enhances aerodynamic performance by allowing controlled twist adjustments, improving fuel efficiency, range, and payload capacity across varying conditions.
Implementation Method 1
The first elastomeric joint deforms to adjust for shear from actuation of the first movable member to a first position during helicopter mode; and to a second position during airplane mode.
Implementation Method 2
a first elastomeric joint disposed between the root portion and the first movable member
Data Source
AI summary
A rotor blade including a root portion adapted to be connected to a helicopter rotor hub for rotation therewith, the root portion having a first edge surface; a first movable member having a first movable surface adjacent to the first edge surface; a first elastomeric joint disposed between the root portion and the first movable member, the first elastomeric joint having an inner surface facing the first edge surface of the root portion and an outer surface facing the movable surface of the first movable member; and an actuating system mounted within the root portion and the first movable member for moving the first movable member. The first elastomeric joint deforms to adjust for shear from actuation of the first movable member to a first position during helicopter mode; and to a second position during airplane mode.