Rotorcraft Standby Engine Power Compensation

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Solution Overview

Problem

Aircraft operating in asymmetric modes with one engine in active and another in standby mode face delays in powering up the standby engine, leading to potential rotor speed reductions and fuel inefficiencies.

Innovation Solution

A method and system for detecting active engine failures in rotorcraft operating in asymmetric regimes, adjusting flight controls to mitigate rotor speed reductions, and commanding an increase in power output from standby engines to maintain stable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a standby engine is operated in standby mode to provide substantially no motive power, then fuel efficiency is improved, but the delay in powering up the standby engine worsens

Engineering Contradiction:

Improvefuel efficiencyVSAvoiddelay in powering up standby engine

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The standby engine is maintained in a pre-conditioned state with essential systems (fuel flow, ignition, lubrication) already activated and ready, allowing rapid transition to full power output when needed, thus reducing the delay while maintaining fuel efficiency during standby operation

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If one engine is operated at high power in active mode, then fuel efficiency is improved, but the rotor speed reduction upon engine failure worsens

Engineering Contradiction:

Improvefuel efficiencyVSAvoidrotor speed stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The flight control system continuously monitors rotor speed and automatically adjusts flight control inputs in real-time following engine failure to compensate for power loss and maintain rotor speed stability, preventing excessive rotor droop

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The standby engine is pre-conditioned with fuel flow and ignition systems ready, enabling immediate power output upon activation to compensate for the failed engine and maintain rotor speed

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11299286B2System and method for operating a multi-engine aircraft

Publication Date: 2022.04.12 PRATT & WHITNEY CANADA CORP

AI summary

The present disclosure provides methods and systems for operating a rotorcraft comprising a plurality of engines configured to provide motive power to the rotorcraft and at least one rotor coupled to the plurality of engines. Failure of an active engine of the rotorcraft is detected when the rotorcraft is operated in an asymmetric operating regime (AOR), in which at least one first engine of the plurality of engines is the active engine and is operated in an active mode to provide motive power to the rotorcraft and at least one second engine of the plurality of engines is a standby engine and is operated in a standby mode to provide substantially no motive power to the rotorcraft. At least one flight control input is adjusted to compensate for a reduction in rotational speed of the at least one rotor resulting from the failure of the active engine. An increase in a power output of the standby engine of the rotorcraft is commanded.