Helicopter Fuselage Differential Frame Fuel Tank Integration
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Solution Overview
Problem
The integration of fuel tanks into helicopter fuselage airframes is complex, requiring multiple fuel bladders and intricate fuel system devices, leading to time-consuming assembly and maintenance processes, with risks of damaging fuel bladders during drilling operations and limitations in structural design.
Innovation Solution
A fuselage airframe design featuring a differential frame with a variable-height lower section and transversal beams that partitions the subfloor compartment into two cells, allowing for the integration of two fuel bladders connected by a middle bladder without the need for interconnecting devices, reducing assembly complexity and enabling easy installation and maintenance without drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If continuous frames and longerons are used to enclose the subfloor compartment, then structural strength and stability are improved, but the fuel tank integration becomes complex requiring multiple fuel bladders and interconnecting devices
Solution Approach 1:
The continuous frame is segmented into two separate frames with a gap between them. This segmentation allows the fuel tank to be integrated directly into the gap without requiring multiple fuel bladders and interconnecting devices, thereby reducing fuel system complexity while maintaining structural strength through the two separate frames
Solution Approach 2:
The fuel tank integration is extracted from the complex multi-bladder system and placed directly into the gap between two frames. This extraction simplifies the overall system by eliminating the need for intermediate transfer pipes and scavenge lines, reducing both device complexity and assembly time
2Quantity of substance
If multiple fuel bladders are used to fill the subfloor compartment, then fuel storage capacity is improved, but assembly time and integration effort increase significantly
Solution Approach 1:
The gap between two frames is used to house a single integrated fuel tank that serves the entire subfloor compartment. This merging approach consolidates multiple fuel storage functions into one unified structure, eliminating the need for multiple separate fuel bladders and their corresponding interconnecting devices, thereby reducing assembly time while maintaining adequate fuel storage capacity
3Ease of manufacture
If drilling operations are performed in the fuel tank area, then structural modifications are enabled, but the risk of damaging fuel bladders increases
Solution Approach 1:
The fuel tank is positioned in the gap between two frames, extracting it from the drilling zone. This positioning eliminates the need for drilling operations in the fuel tank area, thereby protecting fuel bladder integrity while still enabling structural modifications through the frame gap without compromising fuel storage reliability
4Ease of operation
If fuel system devices are conducted through structural elements, then fuel transfer functionality is achieved, but the structural elements require cut-outs reducing their structural integrity
Solution Approach 1:
The fuel transfer functionality is extracted from the traditional approach of conducting devices through structural elements. Instead, fuel transfer is achieved through the gap between two frames where the fuel tank is directly integrated, eliminating the need for cut-outs in structural elements and preserving their full structural integrity while maintaining fuel transfer capability
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a fuel tank (19) and a differential frame (3) in a fuselage airframe (1) of a helicopter, the fuel tank (19) being installed between the fuselage lower cover shell (4) and the floor panel (5). The differential frame (3) separates the fuel tank (19) into two individual compartments, the differential frame (3) having a web (15) below the floor panel with a variable-height (23) with a minimum height at the symmetry axis (18) of the fuselage cross-section and a maximum height at lateral frame roots regions (27). A transversal beam (7) is attached at each of its both ends to the differential frame (3) bridging the entire variable-height (23) of the differential frame (3) and the fuel tank (19) with two front and rear fuel bladders (20, 21) covering both individual tank compartments with a middle bladder (22) installed between the transversal beam (7) and the variable-height web (15) of the differential frame (3).