Aircraft Rear Fuselage Stiffness via Non-Structural Cut-Out
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Solution Overview
Problem
Conventional aircraft rear fuselage designs with box-type central elements for horizontal tail planes require structural openings, leading to stiffness reduction, complex manufacturing, and difficult maintenance, as well as weight and assembly challenges.
Innovation Solution
The design relocates the cut-out for the horizontal tail plane to a non-structural part of the rear fuselage, allowing for a unitary closed frame assembly and a detachable fairing, which simplifies manufacturing, reduces weight, and facilitates easier assembly and maintenance by containing the pivot axis within a horizontal plane below the closed frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a structural opening is created in the rear fuselage for the box-type central element, then the horizontal tail plane can be emplaced, but the stiffness of the rear fuselage section is reduced
Solution Approach 1:
The invention extracts the horizontal tail plane emplacement requirements from the structural part of the rear fuselage by providing a cut-out in the non-structural part only. This allows the box-type central element to be emplaced without creating openings in the load-bearing frames, thereby maintaining fuselage stiffness while enabling HTP installation.
Solution Approach 2:
The invention segments the rear fuselage into structural and non-structural parts, with the cut-out located exclusively in the non-structural portion. This segmentation allows the structural frames to remain continuous and intact, preserving their stiffness-carrying capability while the non-structural part accommodates the HTP cut-out.
2Ease of manufacture
If a cut-out is provided in the structural part of the rear fuselage, then the horizontal tail plane can be installed, but the manufacturing complexity increases
Solution Approach 1:
The invention extracts the cut-out requirement from the structural part of the rear fuselage and relocates it to the non-structural part. This eliminates the need to split structural frames or create complex openings in load-bearing elements, significantly reducing manufacturing complexity while still allowing HTP installation.
Solution Approach 2:
By segmenting the rear fuselage into structural and non-structural zones, the invention confines the cut-out to the non-structural zone. This segmentation simplifies manufacturing because the structural part can be built as continuous, intact frames without the complexity of accommodating openings or splits.
3Ease of repair
If the tail cone is removed to access the box-type central element, then maintenance can be performed, but the maintenance time and complexity increase
Solution Approach 1:
The invention extracts the box-type central element from deep within the fuselage structure by providing a cut-out in the non-structural part that allows direct access. This eliminates the need to remove the tail cone for maintenance, as the HTP and its actuators can be accessed directly through the cut-out, significantly reducing maintenance time.
Solution Approach 2:
The cut-out in the non-structural part acts as an intermediary access point to the HTP components. Instead of requiring complete disassembly (tail cone removal), this intermediary opening provides direct pathways for maintenance personnel to reach and service the box-type central element and THSA actuators.
4Adaptability or versatility
If split frames with joining requirements are used in the structural part, then the horizontal tail plane can be accommodated, but the assembly complexity increases
Solution Approach 1:
The invention extracts the HTP accommodation requirements from the structural frames by providing a cut-out in the non-structural part. This allows the structural frames to remain as simple, continuous units without splits or complex joinings, while the non-structural part is designed to accommodate the HTP through the cut-out.
Solution Approach 2:
By segmenting the rear fuselage into structural and non-structural parts, the invention allows the structural part to use simple, continuous frames for strength, while the non-structural part is segmented to accommodate the HTP cut-out. This segmentation resolves the conflict between structural integrity and HTP accommodation.
Data Source
AI summary
A rear fuselage section of an aircraft comprises at least one closed frame constructed as a unitary body, and a horizontal tail plane comprising a box-type central element and two lateral torsion boxes, said horizontal tail plane trimmable with respect to a pivot axis. The horizontal tail plane is mounted at the closed frame and the pivot axis is contained in a horizontal plane below the lowest end of said closed frame.