Aircraft Engine Thrust Correlation Model for Ground-to-Flight Accuracy
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Solution Overview
Problem
Existing methods for determining thrust in aircraft engines, particularly unducted engines, lack accuracy and require specialized testing hardware to simulate in-flight conditions, leading to inconsistent and unreliable thrust measurements.
Innovation Solution
A method and apparatus for determining thrust that involves ground testing with an analytical model calibrated using full-power engine operation under simulated in-flight conditions, measuring both torque and thrust, and applying modifiers to correct for errors, allowing for highly accurate predictions of in-flight performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specialized testing hardware is used to simulate in-flight conditions, then thrust measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a correlation model that copies the relationship between engine parameters and thrust performance based on ground test data. Instead of requiring complex flight testing hardware, the system creates a mathematical representation of thrust behavior that can be applied to predict in-flight performance from simpler ground-based measurements.
Solution Approach 2:
The patent replaces the need for complex mechanical flight testing hardware with a computational approach. By using measured engine parameters (torque, shaft speed, environmental conditions) fed into a correlation model, the system substitutes physical flight testing infrastructure with mathematical calculations that predict thrust performance.
2Device complexity
If ground testing is performed without simulating in-flight conditions, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent employs a feedback mechanism where the correlation model is continuously refined using measured data from ground tests. The system compares predicted thrust values with actual measurements and adjusts the correlation coefficients accordingly, allowing ground testing equipment to achieve flight-relevant accuracy through iterative calibration.
Solution Approach 2:
The patent accounts for in-flight conditions by incorporating environmental parameters (temperature, pressure, humidity) into the correlation model. By measuring these parameters during ground tests and adjusting the correlation calculations accordingly, the system compensates for the lack of actual flight conditions while maintaining measurement precision.
3Ease of operation
If thrust is calculated using standard engine parameters (torque and shaft speed), then ease of operation is improved, but measurement precision deteriorates due to unaccounted errors
Solution Approach 1:
The patent enhances the simple torque-times-shaft-speed calculation by introducing correction factors derived from measured data. The system maintains the simplicity of the basic formula while adding correlation coefficients that account for real-world deviations, thus preserving ease of operation while improving measurement precision.
Solution Approach 2:
The correlation model serves multiple functions: it corrects thrust calculations, predicts performance under different conditions, and adapts to various engine types. This universal approach allows the same enhanced calculation method to be applied across different engine configurations without requiring complex engine-specific modifications.
Data Source
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AI summary
Approaches are provided that evaluate overall engine thrust and potentially other engine operating parameters statically on the ground for an aircraft engine (204). The results of the evaluation are used to produce a correlated analytical model (210) that accurately models engine performance. Once testing on the ground is complete and correlated model determined, the engine (204) is placed aboard an aircraft and tested in flight. Thrust of the engine (204) can be determined at least in part using the correlated model and this determined thrust is compared to the desired thrust.