Rotorcraft Windshield Strapped Assembly Bird Strike Deflection

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Solution Overview

Problem

Helicopter windshields are vulnerable to damage from bird strikes, leading to potential penetration and injury to pilots, as existing designs lack sufficient impact resistance and deformation capabilities to deflect such objects effectively.

Innovation Solution

A strapped windshield assembly for rotorcraft featuring independent straps made of metal or composite materials, spaced every 4-6 inches along the windshield edge, which can flex and move relative to the airframe, combined with corner supports and secondary straps to absorb and distribute impact forces, allowing the windshield to deform and deflect striking objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid windshield structure is used, then structural strength is improved, but impact resistance and deformation capability deteriorate

Engineering Contradiction:
Improvestructural strengthVSAvoidimpact resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The windshield assembly is segmented into multiple independent straps (typically 3-5 straps) spaced along the edges of the windshield. Each strap can move independently relative to the airframe and to each other, allowing the structure to deform and absorb impact energy while maintaining overall structural integrity. This segmentation resolves the contradiction by enabling both strength (through multiple support points) and impact resistance (through independent movement capability).

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The windshield mounting system transitions from a static rigid connection to a dynamic system where straps can move independently. The straps are attached to the airframe at corners and along edges, allowing them to flex and relocate during impact events. This dynamic capability enables the windshield to absorb strike forces while maintaining structural strength through the distributed strap configuration.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If the windshield is rigidly attached to the airframe, then structural stability is improved, but deformation capability during impact deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoiddeformation capability
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The rigid attachment is segmented into multiple independent strap connections at corners and along edges. Each strap maintains structural stability through its attachment points while allowing controlled deformation and movement during impact. The segmentation enables the system to maintain overall stability while adapting to impact forces through individual strap movement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The attachment system changes its mechanical parameters from fixed rigid connections to flexible connections with controlled movement ranges. The straps maintain structural stability under normal conditions but can deform and relocate during impact events, changing their positional and mechanical parameters to absorb energy while maintaining overall windshield stability.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If traditional windshield mounting is used, then device simplicity is improved, but impact energy absorption deteriorates

Engineering Contradiction:
Improvemounting structure simplicityVSAvoidimpact energy absorption
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The mounting structure is segmented into multiple independent straps instead of a single rigid frame or continuous attachment. This segmentation increases energy absorption capability by allowing each strap to independently deform and absorb impact energy, while the overall device complexity remains relatively simple with straightforward strap attachments at corners and along edges.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flexible strap configuration provides beforehand cushioning by being pre-configured to allow controlled deformation and movement during impact events. The straps are designed with appropriate flexibility and attachment characteristics that enable them to absorb impact energy through elastic deformation and relocation, protecting the windshield and occupants from full impact forces.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution significantly enhances the impact resistance of windshields, reducing the likelihood of cracking, breaking, or separation from the airframe during strikes, effectively deflecting objects and minimizing stress on the windshield and airframe.

Implementation Method 1

The straps can have a modulus of elasticity of 8-12 millions of pounds per square inch (MSI) (55-83 Giga Pascal (GPa))

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

allowing the windshield to deform and deflect striking objects

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP2910464B1Strapped windshield assembly for rotorcraft
Publication Date: 2018.11.07 BELL HELICOPTER TEXTRON INC
  • EP2910464B1 patent drawingFigure 1
  • EP2910464B1 patent drawingFigure 2
  • EP2910464B1 patent drawingFigure 3~4

AI summary

This description relates to a strapped windshield assembly for a rotorcraft (200,300). In some implementations, the rotorcraft (200, 300) includes an airframe (202, 302, 502), a windshield (204, 504), and a plurality of independent straps (210, 510) connected to the airframe (202, 302, 502) and the windshield (204, 504), the straps (210, 510) operative to move independently with respect to one another. The independent movement of the straps (210, 510) allow relative movement of portions of the windshield (204, 504) in response to a strike. In some implementations, the straps (210, 510) are spaced every 4-6 inches along an edge of the windshield (204, 504). In some implementations, the straps (210, 510) are over an edge of the windshield (204, 504). The straps (210, 510) can have a modulus of elasticity of 8-12 millions of pounds per square inch (MSI). The windshield (204, 504) can include polycarbonate material.