Aircraft Engine Thrust Rating Using Lock-and-Lapse References
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Solution Overview
Problem
Current engine thrust management processes are inefficient as they require complex calculations and updates during airplane development, testing, and production, with initial thrust estimates needed early in the process but accurate thrust versus N1 relationships only finalized after flight tests, leading to convoluted sequences in system design.
Innovation Solution
A method to determine thrust targets by locking idle, climb, and take-off thrust reference targets based on temperature, airspeed, and altitude, using a lock and lapse architecture that adjusts these targets with real-time conditions and interpolates commanded thrust targets from these references, allowing for more accurate and efficient engine thrust management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the conventional thrust management process is used, then the thrust versus N1 relationship is accurately finalized after flight tests, but the system design is delayed and the development process becomes convoluted
Solution Approach 1:
The patent applies preliminary action by establishing a preliminary thrust model using initial estimated thrust values before flight tests are completed. The system uses these estimates to develop PEPM architecture and thrust management software early in the development process, then refines the model with actual flight test data later, eliminating the need to wait for flight tests before software development can proceed
Solution Approach 2:
The patent segments the thrust determination process into distinct phases: an initial phase using estimated thrust values for software development, and a refinement phase using actual flight test data. This segmentation allows parallel development of software and hardware/test procedures without sequential dependencies
2Productivity
If the thrust management software is developed early in system development, then the development process is accelerated, but the thrust estimates must be updated after flight tests
Solution Approach 1:
The patent establishes a preliminary thrust model with estimated values that enables early software development. This preliminary model is deliberately designed to be replaceable and updatable, allowing the system to progress with initial estimates and later incorporate refined values from flight tests without requiring complete redesign
Solution Approach 2:
The patent implements a dynamic thrust model that transitions from static estimated values to updated values based on flight test data. The system architecture allows the thrust model to evolve and adapt as new information becomes available, rather than requiring a fixed model from the outset
3Measurement precision
If the conventional sequential process is used, then accurate thrust data is obtained, but the critical flows of airplane development are delayed
Solution Approach 1:
The patent enables preliminary thrust rating determinations using estimated values, allowing airplane development to proceed through critical flows without waiting for final thrust characterization. The preliminary ratings are sufficient for early development activities while more accurate ratings are finalized in parallel based on flight test data
Data Source
AI summary
An engine thrust rating process and system for controlling engine thrust during flight of an aircraft and/or to support an airplane development program (including design, validation testing, and production of airplane systems, airplane dispatch and operation tools). The thrust rating process uses thrust ratios derived from thrust expressed in power rather than engine rotor speed (N1). In one or more examples, the thrust rating architecture is based on “Max Rated Thrust” tables and the power setting parameter “PSP” being calculated at the end of the process instead of at the beginning of the process (unlike conventional procedures), thereby enabling the system software development early as needed to support the airplane development phase. This concept also yields improvements such as simplified control logic, optimized engine performance and engine life.