Trailing-Arm Landing Gear With Fuse-Led Compact Collapse
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Solution Overview
Problem
Integrating aircraft landing gear into smaller or unconventional aircraft with limited space between the gear and the cabin or fuel tanks is challenging, as existing designs do not efficiently accommodate compact collapse and fail safely under extreme loads without compromising structural integrity.
Innovation Solution
The aircraft landing gear assembly features a first leg assembly with a trailing arm that rotates about a trailing arm axis, equipped with a shock absorber to dampen loads within a normal range and a fuse member that fails under excessive loads, allowing the trailing arm to rotate beyond the normal range, and a common pintle that rotates between extended and retracted configurations to accommodate compact collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the landing gear is designed with a fixed trailing arm configuration, then the structural integrity is maintained under normal loads, but the landing gear cannot collapse compactly under extreme loads to fit into confined spaces
Solution Approach 1:
The trailing arm is divided into multiple segments that can rotate relative to each other about a trailing arm axis. Under extreme loads, the shock absorber fails and allows these segments to rotate, enabling compact collapse while maintaining structural integrity during normal operation
Solution Approach 2:
The trailing arm configuration transitions from a fixed rigid structure under normal loads to a dynamic multi-segment structure under extreme loads. The ability to rotate about the trailing arm axis provides adaptability between these two states, allowing compact collapse when needed
2Reliability
If the shock absorber is designed to limit rotation within normal operating range, then the structural integrity is maintained, but the landing gear cannot fail safely beyond the normal range under extreme loads
Solution Approach 1:
The fuse member is pre-configured to fail at a predetermined load threshold. This preliminary design ensures that when extreme loads occur, the shock absorber will fail in a controlled manner, allowing safe rotation beyond the normal operating range without compromising overall safety
Solution Approach 2:
The fuse member acts as an intermediary element between the shock absorber and the trailing arm. It mediates the transition from a constrained state (within normal operating range) to an unconstrained state (beyond normal range) by failing at a predetermined load, enabling safe failure modes
3Adaptability or versatility
If the landing gear assembly is designed for large commercial aircraft with ample space, then the cabin intrusion is prevented, but the design is not suitable for smaller aircraft with limited space between landing gear and cabin
Solution Approach 1:
The landing gear assembly transitions from a static configuration to a dynamic one that can adapt its volume. The multi-segment trailing arm with rotation capability allows the gear to collapse into a compact configuration, making it suitable for both large and small aircraft with different space constraints
Solution Approach 2:
The landing gear design achieves universality by being adaptable to different aircraft types. The compact collapse capability enabled by the rotating trailing arm segments allows the same design to be used in both large commercial aircraft and smaller unconventional aircraft with limited space
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 safe and compact integration of landing gear into confined spaces, allowing for efficient operation and failure modes that prevent intrusion into the cabin or fuel tanks, suitable for smaller and unconventional aircraft designs.
Implementation Method 1
The first shock absorber may be configured to dampen rotation of the first trailing arm about the first trailing arm axis within a normal operating range
Data Source
AI summary
An aircraft landing gear assembly is disclosed including a leg assembly having a trailing arm configured to rotate about an axis and carry a wheel, a shock absorber coupled to the arm and enabled to dampen rotation of the arm about the axis within a normal operating range, and to limit the rotation of the arm about the first trailing arm axis to the normal operating range, and a fuse member coupled to the shock absorber. The fuse member is configured to fail in the event a vertical load on the wheel exceeds a pre-determined threshold, wherein failure of the fuse member allows the first trailing arm to rotate about the first trailing arm axis beyond the normal operating range.