Kicked Spar Design for Aircraft Control Surface Actuator Integration
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Solution Overview
Problem
In aircraft with composite structural systems, it is challenging to accommodate structural fittings and actuators in thin cross-sections without compromising the spar's position near the hinge line, leading to excessive moment arms and space constraints.
Innovation Solution
A spar design with spanwise bends or 'kicks' is implemented, allowing chordwise offset of the spar web to provide additional space for actuator fittings and structural requirements, maintaining the spar's optimal position near the hinge line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fittings are placed in a standard structural arrangement within thin sections, then the spar can be located close to the hinge line, but excessive moment arms are required which compromises the joint
Solution Approach 1:
The spar web is bent out of the flat plane into a three-dimensional kicked configuration, creating chordwise offsets that provide additional space for fittings while maintaining the spar's proximity to the hinge line. This dimensional change allows fittings to be positioned optimally without excessive moment arms.
Solution Approach 2:
The spar web features localized kicks or bends at specific spanwise locations where fittings are required, rather than changing the entire spar geometry. This allows chordwise offset and additional fitting space to be introduced only where needed, maintaining structural efficiency elsewhere.
2Ease of operation
If the spar is located close to the hinge line to optimize aerodynamic performance, then control surface efficiency is improved, but space for fittings and joints is constrained
Solution Approach 1:
By bending the spar web out of the flat chordwise plane into a kicked three-dimensional configuration, the design creates additional chordwise space for fittings without moving the spar away from the hinge line, thus preserving control surface efficiency while accommodating fitting space requirements.
Solution Approach 2:
The spar web is segmented into multiple regions with different orientations through the kicks, allowing each segment to serve a specific function: some segments maintain proximity to the hinge line for aerodynamic efficiency, while other segments provide offset space for fittings and joints.
3Weight of moving object
If thin cross-sections are used to reduce weight, then structural efficiency is improved, but it becomes difficult to fit structural fittings and actuators
Solution Approach 1:
The kicked spar web configuration utilizes the third dimension (chordwise offset through bending) to create additional space for fittings and actuators within the thin cross-section, allowing thin-walled lightweight construction while still accommodating all necessary structural elements.
Solution Approach 2:
The thin cross-section is maintained overall for weight reduction, but localized kicks in the spar web create specific regions with increased chordwise dimension where fittings and actuators can be accommodated, combining the benefits of thin-section construction with fitting accommodation capability.
Data Source
AI summary
An aerodynamic structure incorporated in an aircraft control surface provides a spar extending along at least a portion of the control surface in a direction and the spar includes a plurality of bends along the direction of extension along the control surface to provide space to accommodate actuator fittings or other structural or operational requirements.