Aircraft Flight Control Device with Mechanical Feedback

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Solution Overview

Problem

Helicopter pilots face stress and complexity in controlling collective pitch due to the need to avoid turbine overspeed and underspeed limits, which are constantly changing during different flight phases, and existing warning systems can be painful and stressful over time.

Innovation Solution

A flight control device with a link lever and mechanical means that provide intuitive force feedback by increasing resistance as the pilot approaches operational limits, allowing the pilot to feel when approaching turbine limits without being blocked, and the ability to redefine these limits based on flight phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If audible or visual alarm systems are used to warn pilots of turbine speed limits, then pilot awareness of limits is improved, but pilot stress and annoyance increase over time

Engineering Contradiction:
Improvepilot awareness of turbine speed limitsVSAvoidpilot stress and comfort
Core Design Contradiction:
Loss of informationVSEase of operation

Solution Approach 1:

The patent implements a mechanical feedback system where a spring-loaded indicator physically contacts the control lever to provide tactile feedback when the turbine approaches speed limits. This haptic feedback mechanism allows pilots to sense limit conditions through touch rather than through annoying audible or visual alarms, thereby maintaining awareness while reducing stress.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If mechanical means are added to provide force feedback to the pilot, then pilot awareness of operational limits is improved, but device complexity increases

Engineering Contradiction:
Improvepilot awareness of operational limitsVSAvoidcontrol system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent introduces a spring-loaded indicator as an intermediary mechanical element that translates turbine speed conditions into physical contact forces on the control lever. This intermediary mechanism provides intuitive tactile feedback without requiring complex electronic sensors, processors, or actuation systems, thereby achieving improved pilot awareness with minimal added complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the control system provides strong resistance to prevent exceeding limits, then turbine protection is improved, but pilot ability to respond to emergencies is reduced

Engineering Contradiction:
Improveturbine protectionVSAvoidpilot emergency response capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements a mechanical stop system that provides increasing resistance as the control lever approaches the limit position, but allows the lever to be forced beyond the stop if necessary. The spring-loaded indicator provides progressive resistance rather than an absolute hard stop, enabling normal operation with protective feedback while allowing emergency override when pilots must exceed limits to respond to critical situations.

Inventive Principle:
Principle #16Partial or excessive action

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 device assists pilots by providing intuitive feedback to avoid damaging the turbine, allowing safe operation near limits while enabling continued movement beyond them in emergencies, and adapts to changing operational limits during different flight phases.

Implementation Method 1

first means for generating a restoring force of the connecting lever about said axis of rotation, the first means being permanently connected to the connecting lever, second means for generating a restoring force

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3271244B1Aircraft flight control device
Publication Date: 2019.05.01 SAFRAN ELECTRONICS & DEFENSE (FR)
  • EP3271244B1 patent drawingFigure 1~6
  • EP3271244B1 patent drawingFigure 2~4
  • EP3271244B1 patent drawingFigure 5~7

AI summary

The invention relates to a flight control device for an aircraft, comprising a link lever, mechanical means for limiting an angular course of the link lever, first means (4) for generating a force for the return of the link lever about said rotational axis, and second means (16) for generating a force for the return of the link lever, which are arranged in parallel to the first means, at least one element of the second means and the link lever comprising mechanical means for the temporary connection thereof, which are arranged so as to be active when the link lever is moved beyond a pre-determined angular position in the angular range so that the second means are connected to the link lever.