Electric Starter Verification for Gas-Turbine Engine Barring
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Solution Overview
Problem
Certain starter types for gas-turbine engines, such as air-turbine starters, may require a source of compressed air, which can reduce dispatch availability and necessitate an auxiliary power unit (APU) for mid-air restarts, increasing weight and complexity, and not all starter types meet certification requirements for ground and mid-air starts.
Innovation Solution
Incorporating both an electric starter and an air-turbine starter, with the electric starter being partially rated to assist the air-turbine starter, allowing mid-air restarts without an APU, and using a bus bar interconnection to minimize weight and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an air-turbine starter is used to start the gas-turbine engine, then the engine can be started on the ground, but an APU is required for mid-air restarts, increasing weight and reducing dispatch availability
Solution Approach 1:
The air-turbine starter is designed to perform multiple functions: ground starting and mid-air restart. By making the same starter unit universal for both operations, the system eliminates the need for separate ground power units and APUs, reducing overall aircraft weight while maintaining full operational capability for both ground and aerial engine starting
2Reliability
If multiple starter types (electric and air-turbine) are included to meet certification requirements, then mid-air restart capability is achieved, but device complexity and weight increase
Solution Approach 1:
The air-turbine starter is designed to universally handle both ground starting and mid-air restart operations. This multi-functionality eliminates the need for separate electric and air-turbine starter systems, thereby reducing device complexity while maintaining full certification compliance for both ground and aerial engine starting capabilities
Solution Approach 2:
The invention extracts and eliminates the APU component from the aircraft system. By using the air-turbine starter for both ground and mid-air operations, the APU is no longer needed, simplifying the overall aircraft architecture and reducing system complexity while maintaining required restart capabilities
3Reliability
If a fully rated electric starter is used to independently start the engine on the ground, then ground starting capability is achieved, but weight increases significantly
Solution Approach 1:
A partially rated electric starter is used that provides sufficient torque and power for ground starting operations. This partial-rating approach delivers the necessary ground starting capability while significantly reducing the weight compared to a fully rated starter designed for all possible operating conditions, achieving an optimal balance between performance and weight
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
Enables mid-air restarts without an APU, reduces weight and mechanical complexity, and meets certification requirements by utilizing a partially rated electric starter in conjunction with an air-turbine starter.
Implementation Method 1
an electric starter and an air-turbine starter configured to start a particular gas-turbine engine
Implementation Method 2
an air-turbine starter configured to start a particular gas-turbine engine
Data Source
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AI summary
An example system includes a first gas-turbine engine configured to propel an aircraft, the first gas-turbine engine comprising a first electric starter, the first electric starter configured to rotate a spool of the first gas-turbine engine; and one or more controllers collectively configured to: cause, following operation of the first gas-turbine engine, the first electric starter to perform barring of the first gas-turbine engine; measure, during the barring of the first gas-turbine engine, values of one or more parameters of the first gas-turbine engine; and determine, based on the values of the one or more parameters, whether the first electric starter is available for use in performing mid-air restart of the first gas-turbine engine.