Aircraft Propulsion System Flight Test: Analysis and Evaluation Challenges and Solutions

2012 ◽  
Author(s):  
Brian A. Binkley ◽  
Donald J. Malloy ◽  
Grant T. Patterson ◽  
Eric R. Hansen ◽  
David S. Kidman
Keyword(s):  
Stability Margin ◽  
Flight Test ◽  
Propulsion System ◽  
Data Sets ◽  
Test Analysis ◽  
Analysis And Evaluation ◽  
Test And Evaluation ◽  
Ground Test ◽  
Total Temperature ◽  
Aircraft Propulsion System

The paper describes the challenges and solution methodologies associated with the flight test and evaluation of the propulsion system for a twin engine military legacy aircraft. Recent flight-test programs evaluated the effects of temperature distortion and biased engine inlet total temperature measurement (TT2) on engine scheduling and compressor stability margin. The challenges are associated with the limited instrumentation and the repeatability of the flight-test points. During the test program it was necessary to employ techniques to extend the usefulness of the data beyond that provided by the acquired and reduced data sets to address the challenges associated with flight-test analysis. The challenges were addressed using mathematical models, engine cycle decks, uninstalled ground-test data, computational fluid dynamics, or some combination of these. Several specific challenges and solutions are described in detail in the paper.

Aircraft Propulsion System Flight Test—Analysis and Evaluation Challenges and Integrated Solutions

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Brian A. Binkley ◽  
Donald J. Malloy ◽  
Grant T. Patterson ◽  
Eric R. Hansen ◽  
David S. Kidman
Keyword(s):  
Stability Margin ◽  
Flight Test ◽  
Propulsion System ◽  
Data Sets ◽  
Test Analysis ◽  
Analysis And Evaluation ◽  
Test And Evaluation ◽  
Ground Test ◽  
Total Temperature ◽  
Aircraft Propulsion System

The paper describes the challenges and solution methodologies associated with the flight test and evaluation of the propulsion system for a twin-engine military legacy aircraft. Recent flight-test programs evaluated the effects of temperature distortion and biased engine inlet total temperature measurement (TT2) on engine scheduling and compressor stability margin. The challenges are associated with the limited instrumentation and the repeatability of the flight-test points. During the test program it was necessary to employ techniques to extend the usefulness of the data beyond that provided by the acquired and reduced data sets to address the challenges associated with flight-test analysis. The challenges were addressed using mathematical models, engine cycle decks, uninstalled ground-test data, computational fluid dynamics, or some combination of these. Several specific challenges and solutions are described in detail in the paper.

Developing Statistically Defensible Propulsion System Test and Evaluation Techniques

2012 ◽  
Author(s):  
David Kidman ◽  
Craig Stevens ◽  
Christopher Moulder ◽  
William Kitto ◽  
James Brownlow ◽  
...  
Keyword(s):  
Air Force ◽  
Uncertainty Propagation ◽  
Flight Test ◽  
The United States ◽  
Propulsion System ◽  
Design Development ◽  
Test And Evaluation ◽  
Operational Test ◽  
Evaluation Techniques ◽  
Aircraft Propulsion

Acquisition of military hardware typically proceeds from design, development, production, and finally to operational use and support. Prior to the full-rate production, both developmental and operational test and evaluation (DT&E, OT&E) must occur to ensure that the system meets military requirements. The United States Air Force (USAF) is continually looking for ways to improve its test and evaluation techniques. Since 1997, Air Combat Command (ACC) has been successfully using Design of Experiments (DOE) to construct and analyze operational test efforts. This paper highlights recent efforts to pursue statistically defensible test techniques to aid developmental test efforts. Defensible testing is a statistical approach similar to DOE by emphasizing the need for better test planning by: • insistence on understanding the system under test; • requiring clear and achievable test objectives; • ensuring system performance is measurable; • requiring that instrumentation accuracy and uncertainty propagation are well understood; • and requiring confidence, power, and performance thresholds. This paper highlights the Air Force Flight Test Center’s (AFFTC) first steps to improve aircraft propulsion system test and evaluation (T&E) through the implementation of statistically defensible test techniques. Background on the AF acquisition process, the Air Force vision for defensible testing, and an aircraft propulsion T&E case study are presented.

Model Selection Made Easy Using Information Theoretics: An Aircraft Propulsion System Modeling Problem

2014 ◽  
Author(s):  
David Kidman ◽  
Craig Stevens ◽  
Todd Remund ◽  
William Kitto
Keyword(s):  
Model Selection ◽  
Air Force ◽  
System Modeling ◽  
Model Development ◽  
The United States ◽  
Propulsion System ◽  
Test And Evaluation ◽  
Aircraft Propulsion System ◽  
System Knowledge ◽  
Aircraft Propulsion

The United States Department of Defense (DoD) is continually looking for ways to improve test and evaluation techniques to ensure systems meet military requirements prior to acquisition. Recently, the DoD has been pursuing the use of statistical methods to improve test and evaluation. This paper highlights statistical methodologies used by the Air Force Test Center to improve aircraft propulsion system Modeling and Simulation (M&S) efforts. The US Air Force has a long history of using M&S (more than 55 years) during aircraft test and evaluation. In the past, M&S usage was primarily in the aircraft performance and flying qualities areas. Now advancing technology and complex integration are resulting in increased M&S use across broader spectrum of technical disciplines, including propulsion. During propulsion testing, models are used to increase system knowledge in T&E areas which include: Test Planning, Execution, Data Analysis and Evaluation. This paper highlights the 412 Test Wing at Edwards AFB first steps to improve aircraft propulsion system T&E through the implementation of statistically defensible model development techniques. Specifically, this paper will provide an example of typical engineer model development strategies based on past experience, system knowledge, relevant physics and subjective evaluations to determine variables used and structure of the model. This paper will also provide insight into a number of statistics-based approaches including stepwise regression, backwards elimination, the inadequacy of using R-squared and an examination into the effects of mulit-collinearity. However, the focus of this paper is on how Information Theory and Akaike’s Information Criteria (AIC) can be easily applied to compare a variety of models and determine the best model available. This paper presents an example of these model development methods applied during a development of a predictive model used for evaluating thrust response of an aircraft engine with a new digital engine control. A case will be made that statistical approaches provide a more mathematically rigorous approach for model selection as compared to traditional approaches based on engineering judgment.

Automated Methods to Calibrate a High-Fidelity Thrust Deck to Aid Aeropropulsion Test and Evaluation

2008 ◽  
Author(s):  
Jeffrey F. Monaco ◽  
David S. Kidman ◽  
Donald J. Malloy ◽  
David G. Ward ◽  
James F. Gist
Keyword(s):  
Parameter Estimation ◽  
Steady State ◽  
Maximum Likelihood ◽  
Modeling And Simulation ◽  
Flight Test ◽  
Empirical Modeling ◽  
High Fidelity ◽  
Diverse Range ◽  
Test And Evaluation ◽  
Ground Test

Modeling and simulation is regularly used to support test and evaluation at the U.S. Air Force aeropropulsion ground and flight test centers. Advanced modeling and simulation tools used to calibrate a high-fidelity thrust program that predicts steady-state and transient operation of a fighter aircraft turbofan engine are discussed in this paper. Maximum likelihood parameter estimation is used to estimate engine-model calibration factors. Empirical modeling techniques are then used to obtain closed-form polynomials characterizing the variations in the calibration factors as functions of engine operating condition. The inferred polynomial relationships are used to constrain the functional form of the calibration factors as part of a final maximum likelihood parameter estimation step. The coefficients of the polynomials are estimated over all ground-test cases simultaneously to minimize the weighted error between ground-test output measurements and thrust-deck predictions. An overview of the modeling and simulation framework is given with examples illustrating how the framework can readily be applied to a diverse range of aeropropulsion test and evaluation tasks. Details of the thrust deck, key variables, and the calibration factors are presented. Calibrated thrust deck predictions are compared with steady-state ground test data; and it is shown how the approach advances the state-of-the-art through methods that are more highly automated and intuitive to the engine analyst. The enhancements that automate the steps to set up a modeling task provide tangible benefits for a variety of test and evaluation applications.

Integrated Test and Evaluation Techniques as Applied to an Inlet Swirl Investigation Using the F109 Gas Turbine Engine

2008 ◽  
Author(s):  
Milt Davis ◽  
Dave Beale ◽  
Yogi Sheoran
Keyword(s):  
Gas Turbine ◽  
System Development ◽  
Engine Performance ◽  
Evaluation Process ◽  
Gas Turbine Engine ◽  
Test Analysis ◽  
Turbine Engine ◽  
Test And Evaluation ◽  
Inlet Swirl ◽  
Ground Test

With increasing emphasis on streamlining the acquisition process, ground-test centers like the Arnold Engineering Development Center (AEDC) are re-evaluating their roles in the development of aerospace systems. Instead of merely providing data from ground-test facilities, the new emphasis challenges AEDC to become a team member that provides knowledge for risk management and decision making during the development and operation of an aerospace system. As a key link in the transition from a laboratory or design concept to an operational system, the capabilities of a ground-test center can provide a tremendous opportunity to reduce the time and cost involved in flight vehicle system development. AEDC has aggressively accepted the challenge and has developed an Integrated Test and Evaluation (IT&E) approach to support aerospace system development efforts. This paper focuses on an integrated test and evaluation process in a joint test and analysis effort between AEDC, the USAF Academy and Honeywell. This paper reports on the role of gas turbine engine/compressor numerical simulations in the test, analysis, and evaluation process in conjunction with an investigation to discern the effects of inlet swirl on the F109 turbofan engine performance and operability.

Effect of Hot Probe Temperature on Ignition of Alcohol-to-Jet (ATJ) Fuel Spray under Aircraft Propulsion System Conditions

2021 ◽  
Author(s):  
Je Ir Ryu ◽  
Austen Motily ◽  
Tonghun Lee ◽  
Riccardo Scarcelli ◽  
Sibendu Som ◽  
...  
Keyword(s):  
Propulsion System ◽  
Fuel Spray ◽  
Hot Probe ◽  
Aircraft Propulsion System ◽  
Aircraft Propulsion
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