Helicopter Tail Boom Watertight Bulkhead Design

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Solution Overview

Problem

Conventional tail booms for helicopters experience weight increase due to reinforced bulkheads for structural stability, which negatively impact the center of gravity and are not necessary for load redistribution, suggesting a need for a lightweight, non-structural bulkhead design that maintains watertightness.

Innovation Solution

A tail boom design featuring a non-structural bulkhead made of a baggy, impermeable fabric attached within a frame, which is structurally integrated but not involved in the overall mechanical behavior of the tail boom, allowing it to be lightweight and simple while maintaining watertightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional reinforced bulkheads are used for structural stability, then the tail boom gains structural strength, but the weight increases significantly

Engineering Contradiction:
Improvestructural strengthVSAvoidbulkhead weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies this principle by replacing rigid metal bulkheads with flexible fabric membranes that are tensioned within the tail boom structure. The fabric bulkheads (e.g., made of Kevlar, nylon, or other high-strength-to-weight materials) provide the necessary separation and structural contribution without the excessive weight of traditional reinforced metal bulkheads, directly resolving the weight-strength contradiction.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the material parameters from dense metal constructions to lightweight fabric materials with high tensile strength. By altering the material composition and structural configuration (from rigid panels to tensioned membranes), the bulkhead weight is reduced while maintaining adequate structural performance for load redistribution.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If metal bulkheads with stiffening elements are used, then structural stability is improved, but maintenance requirements increase due to crack susceptibility

Engineering Contradiction:
Improvestructural stabilityVSAvoidmaintenance requirements
Core Design Contradiction:
Stability of the object's compositionVSEase of repair

Solution Approach 1:

The flexible fabric bulkheads eliminate the crack susceptibility inherent in rigid metal constructions near the tail rotor. The fabric materials are inherently resistant to fatigue cracking and can be easily replaced if damaged, significantly reducing maintenance requirements while maintaining structural stability through proper tensioning and material selection.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The fabric bulkheads are designed as replaceable components that can be easily installed and removed. If damaged, the entire bulkhead can be replaced without complex repair procedures, treating the bulkhead as a consumable component that simplifies maintenance compared to permanent metal structures requiring inspection and repair.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Force

If flat metal bulkheads are used for load redistribution, then load-bearing efficiency is improved, but the design complexity and reinforcement requirements increase

Engineering Contradiction:
Improveload redistribution efficiencyVSAvoiddesign complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The tensioned fabric bulkheads achieve load redistribution through membrane tension rather than rigid panel stiffness. The fabric is stretched taut within the tail boom structure, creating an efficient load path that redistributes forces without requiring complex stiffening elements, ribs, or reinforcement features, thereby reducing design complexity while maintaining load-bearing efficiency.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP3805091B1A bulkhead for a boom of an aircraft
Publication Date: 2021.08.25 AIRBUS HELICOPTERS DEUT GMBH
  • EP3805091B1 patent drawingFigure 1
  • EP3805091B1 patent drawingFigure 2
  • EP3805091B1 patent drawingFigure 3

AI summary

The present embodiments relate to a boom for an aircraft, and, more particularly, to a tail boom 3 for a helicopter 1, whereby the tail boom 3 may comprise a watertight compartment 7 and watertight bulkheads 5, 6. The watertight bulkheads 5, 6 may close at least one end of watertight compartment 7. Watertight bulkhead 5, 6 may include attachment device 8, frame 12, and watertight fabric 11.