Vertical Stabilizer Base Rib Assembly Connection
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Solution Overview
Problem
Current configurations for connecting vertical stabilizers to aircraft fuselage are difficult to install and maintain, especially in confined spaces, and pose challenges for in-service inspection due to complex fastening systems and orientations.
Innovation Solution
The proposed solution involves a base rib assembly with opposing middle longitudinal lugs and lateral lugs positioned along the front and rear of the base rib, secured to the fuselage through clevises and retaining members, allowing for a more straightforward attachment and alignment of the vertical stabilizer to the fuselage, reducing complexity and improving accessibility for inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If lugs and standard dual wall clevises are used between the vertical stabilizer and the fuselage oriented in longitudinal direction with additional lateral lugs positioned between each longitudinal lug and clevises, then the connection strength is improved, but the installation difficulty increases due to required attachment of lateral lugs between mid spars
Solution Approach 1:
The connection system is divided into longitudinal lugs for primary structural attachment and lateral lugs for secondary positioning, allowing independent installation sequences that simplify the overall assembly process while maintaining connection strength
Solution Approach 2:
Lateral lugs are pre-positioned on the vertical stabilizer before attachment to the fuselage, eliminating the need for complex mid-spar access during final assembly and reducing installation difficulty
2Reliability
If multiple fittings and fasteners are positioned in confined spaces between the vertical stabilizer and the fuselage, then the connection reliability is improved, but the ease of inspection deteriorates due to difficult access in confined spaces
Solution Approach 1:
Access panels are introduced as intermediary elements that provide remote access to fasteners and connection points, allowing inspection and maintenance without direct access to confined spaces between the vertical stabilizer and fuselage
Solution Approach 2:
Inspection ports are nested within the existing structure of the vertical stabilizer or fuselage, providing access to critical connection points while maintaining the overall aerodynamic shape and structural integrity
3Ease of operation
If lugs and clevises are oriented only laterally and positioned along the front and rear spar, then the ease of installation is improved, but the structural stability deteriorates due to insufficient mid-spar support
Solution Approach 1:
Different regions of the vertical stabilizer are equipped with different lug configurations - front and rear spars have lateral lugs for easy installation, while mid-spar regions have longitudinal lugs for enhanced structural stability, creating locally optimized connection points
Data Source
AI summary
An aircraft has a vertical stabilizer having a multi-spar box and a base rib assembly secured to the multi-spar box. The base rib assembly has a pair of middle longitudinal lugs between a front and rear of the base rib assembly, a pair of front lateral lugs along the front of the base rib assembly, and a pair of rear lateral lugs along the rear of the base rib assembly. There are no lateral lugs between the pairs of middle lugs. A pair of middle clevises extend through corresponding apertures in an outer skin of the fuselage and are secured to one of the plurality of frame members and a plurality of retaining members are inserted through mounting holes in each middle longitudinal lug and mounting holes in each middle clevis to secure the vertical stabilizer to the aircraft fuselage.