Suspended-Load Cable Sock for Hover Aircraft Rebound Containment

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Solution Overview

Problem

Hovering aircrafts face safety risks due to elastic rebound of cables or ropes upon breakage, which can impact the aircraft's rotors, necessitating a solution to contain this rebound without weakening the materials or increasing weight, while allowing easy inspection and maintaining protection against atmospheric agents.

Innovation Solution

The use of a sock or tubular structure surrounding the cables or ropes, designed to contain the elastic return of the broken material, with a greater length than the free length of the cable or rope, ensuring the material remains inside and preventing damage to the aircraft, and made of lightweight, easy-to-inspect materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a steel cable or rope is used for suspension operations, then the structural strength and load-bearing capacity are improved, but the elastic rebound upon breakage increases the risk of impacting the aircraft

Engineering Contradiction:
Improveload-bearing capacityVSAvoidelastic rebound risk
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

A sock or tubular structure is introduced as an intermediary element between the cable/rope and the aircraft. This mediator contains the elastic rebound within its confines, preventing direct impact on the aircraft while allowing the cable to maintain its full structural strength for load-bearing operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The sock is pre-positioned around the cable before breakage occurs. This preliminary protective measure is already in place when breakage happens, immediately containing the elastic rebound trajectory and preventing harmful effects before they can reach the aircraft.

Inventive Principle:
Principle #9Preliminary anti-action

2Reliability

If the sock or tubular structure is made longer to contain the elastic rebound, then the safety protection is improved, but the weight of the aircraft increases

Engineering Contradiction:
Improvesafety protectionVSAvoidaircraft weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The optimal length of the sock is determined by calculating the specific elastic rebound characteristics of the cable or rope it protects. This parameter optimization ensures the sock is long enough to contain the rebound but not excessively long, minimizing weight while maintaining safety.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If the sock or tubular structure is made more protective, then the protection against atmospheric agents and impact damage is improved, but the ease of inspection deteriorates

Engineering Contradiction:
Improveprotection against atmospheric agentsVSAvoidinspection difficulty
Core Design Contradiction:
Object-affected harmful factorsVSDifficulty of detecting and measuring

Solution Approach 1:

A flexible sock rather than a rigid enclosure is used. This flexible shell provides protection against atmospheric agents and impact damage while remaining translucent or semi-transparent, allowing visual inspection of the cable condition through the material without compromising protective functionality.

Inventive Principle:
Principle #30Flexible shells and thin films

4Reliability

If the structural properties of the rope are altered to reduce elastic rebound, then the safety is improved, but the strength and stiffness of the rope are weakened

Engineering Contradiction:
ImprovesafetyVSAvoidrope strength and stiffness
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

Instead of trying to eliminate the elastic rebound property of the rope, the invention accepts and utilizes this characteristic by containing it within the sock. The harmful rebound energy is converted into a contained phenomenon that can be managed, allowing the rope to maintain its optimal strength and stiffness for load-bearing while the sock manages the rebound consequence.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively reduces the risk of damage from elastic rebound, maintains the structural integrity of the cables or ropes, and allows for easy inspection, while keeping the aircraft weight minimal and protecting against environmental hazards.

Implementation Method 1

In the event of breakage, the steel cable in the first solution of the known type or the rope in the second solution of the known type can be subject to an elastic rebound directed upwards, that is towards the helicopter.

Methodology Applied
Scientific EffectElastic rebound: Elasticity

Data Source

PatentEP3915874B1Aircraft capable of hovering and method for transporting a load suspended from such aircraft
Publication Date: 2023.01.11 LEONARDO SPA
  • EP3915874B1 patent drawingFigure 1
  • EP3915874B1 patent drawingFigure 2
  • EP3915874B1 patent drawingFigure 3

AI summary

There is described an aircraft (1) configured to be able to hover, comprising a fuselage (2); and a support element (55) adapted to support a load (51), made of elastically deformable material and constrained to said fuselage (2); the support element (55) being movable in an operating position in which it is arranged at least partially outside said fuselage (2) and supports said load (51); the aircraft (1) comprises a sock (20, 60) surrounding the support element (55) arranged in said operating position; the sock (60) is configured to contain the elastic return of the support element (55), in case the support element (55) arranged in said operating position is sheared off.