Aircraft Landing Gear With Forward-Canted Body Gear for Steering
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Solution Overview
Problem
Large airplanes face challenges in adding wheels to main landing gear without disrupting the airplane configuration, leading to steering inefficiencies, increased turn radius, tire scrubbing, and loading issues due to fore-aft offsets between wing and body landing gears.
Innovation Solution
A body landing gear (BLG) is mounted to the wing landing gear (WLG) wheel well aft bulkhead with a forward cant angle, minimizing the fore-aft offset and preserving the existing WLG configuration, using a fixed truss structure with drag braces and actuators for deployment and stowage, maintaining the primary load paths and reducing redesign requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If additional wheels are added to main landing gear to increase total brake mass and distribute loads, then pavement loading is improved and wheel/tire/brake loads are distributed, but airplane configuration is disrupted and steering efficiency decreases
Solution Approach 1:
The landing gear system is divided into separate wing landing gear (WLG) and body landing gear (BLG) components, each with independent wheel assemblies. This segmentation allows the BLG to be positioned with a forward cant angle to improve steering efficiency while the WLG provides additional load-bearing capacity, resolving the conflict between load distribution and steering performance.
Solution Approach 2:
The body landing gear is positioned in a different longitudinal dimension relative to the wing landing gear, with the BLG located aft and canting forward. This dimensional arrangement allows the BLG wheel to align more closely with the airplane's center of gravity, improving steering efficiency while the combined WLG-BLG system distributes loads across multiple contact points.
2Volume of moving object
If body landing gear is mounted aft of wing landing gear to stow in limited volume, then volume constraint is satisfied, but fore-aft offset increases causing decreased steering efficiency and increased turn radius
Solution Approach 1:
The body landing gear is designed with an asymmetric forward cant angle relative to the aircraft fuselage axis. This asymmetric configuration allows the BLG to be mounted aft in the limited volume while the forward cant positions the wheel closer to the center of gravity in the longitudinal direction, improving steering efficiency and reducing turn radius despite the aft mounting location.
3Ease of operation
If forward cant angle is applied to body landing gear to improve steering efficiency, then steering efficiency increases and fore-aft offset is reduced, but structural complexity increases
Solution Approach 1:
The forward cant angle structure of the body landing gear is integrated with the existing wing landing gear wheel well bulkhead and keel beam structure. By merging the BLG mounting structure with the existing primary structure, the forward cant geometry is achieved without adding separate complex structural components, thus improving steering efficiency while minimizing structural complexity.
Data Source
AI summary
A wheeled support structure is presented and may include a shock absorber strut assembly comprising a wheel, a truss structure, a drag brace, and a pivot joint. The pivot joint may connect the truss structure to the drag brace. The drag brace may have an upper drag brace that may be pivotingly attached to a vehicle, and may be pivotingly attached to a lower drag brace. The lower drag brace may be pivotingly attached to the upper drag brace, and may be pivotingly attached to the truss structure. The drag brace may be configured to move between a deployed position and a stowed position. The truss structure may be configured to pivotably attach to the vehicle.