Landing Gear Trunnion Structure for Compact Yehudi Integration

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Solution Overview

Problem

Existing landing gear structures for aircraft with composite airframes face challenges in integrating with the wing structure, particularly in the Yehudi area, leading to increased space requirements and reduced aircraft efficiency.

Innovation Solution

A support structure comprising a trunnion assembly with first and second trunnion parts mounted on opposing sides of the wing spar, a fuse pin block, and a frame that supports the landing gear pin, allowing it to pivot between retracted and extended orientations, eliminating the need for a main gear beam.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a traditional main gear beam configuration is used, then the landing gear provides adequate structural support and stability, but the Yehudi area increases and aircraft efficiency decreases

Engineering Contradiction:
Improvestructural supportVSAvoidaircraft efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent removes the traditional main gear beam from the landing gear configuration. Instead of using a large main gear beam that occupies significant space in the Yehudi area, the invention extracts this component and replaces it with a compact trunnion assembly that achieves the same structural support function with minimal space requirements, thereby maintaining strength while improving aircraft efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent repositions the trunnion assembly from a conventional location to be integrated within the wing spar structure. By moving the support function into a different spatial dimension (within the spar rather than as a separate external beam), the design achieves adequate structural support without increasing the Yehudi area, thus resolving the contradiction between strength and aircraft efficiency

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Weight of moving object

If composite materials are used for the airframe, then weight is reduced, but the landing gear must be attached in a manner to distribute loads to protect the airframe

Engineering Contradiction:
Improveairframe weightVSAvoidattachment complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The trunnion assembly is divided into multiple discrete components including forward and aft trunnions, support fittings, backup fittings, and fuse pins. This segmentation allows each component to be independently designed and positioned to optimally distribute loads across the composite airframe structure, protecting it from concentrated stresses while maintaining the weight benefits of composite materials

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent incorporates backup fittings and fuse pins at specific critical locations within the trunnion assembly. These localized reinforcement elements provide enhanced load distribution and protection precisely where the composite airframe is most vulnerable, allowing the use of lightweight composite materials while ensuring structural integrity through targeted reinforcement rather than uniform complexity

Inventive Principle:
Principle #3Local quality

3Ease of operation

If adequate space is provided to stow the landing gear, then the landing gear can be fully retracted, but the Yehudi area increases and aircraft efficiency is reduced

Engineering Contradiction:
Improvelanding gear stowageVSAvoidaircraft efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The landing gear components are nested within the wing spar structure during retraction. The trunnion assembly and associated fittings are positioned inside the spar's internal volume, allowing the landing gear to be fully stowed without requiring additional external space. This nesting approach enables complete retraction while minimizing the Yehudi area footprint, thus maintaining ease of operation while improving aircraft efficiency

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4059836B1Support structure for an aircraft landing gear
Publication Date: 2025.09.03 THE BOEING CO
  • EP4059836B1 patent drawingFigure 1
  • EP4059836B1 patent drawingFigure 2~3
  • EP4059836B1 patent drawingFigure 4

AI summary

A support structure (10) to mount landing gear (90) to a wing spar (104) of an aircraft. The support structure includes a trunnion assembly (18) having a first trunnion (20) and a second trunnion (30) that are connected together with the first trunnion positioned on a first side of the wing spar and a second trunnion positioned on an opposing second side of the wing spar. The trunnion assembly is configured to support a first section of the landing gear.