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.

USAF Enterprise-Wide Initiative to Improve Aeropropulsion Test and Evaluation

2010 ◽  
Author(s):  
David S. Kidman ◽  
Michael L. Dent ◽  
Donald J. Malloy
Keyword(s):  
United States ◽  
Air Force ◽  
United States Air Force ◽  
State Of The Art ◽  
Future Generation ◽  
The United States ◽  
Propulsion Systems ◽  
Test And Evaluation ◽  
Strategic Goals ◽  
Development Processes

In October of 2009, the United States Air Force (USAF) Test and Evaluation (T&E) community initiated work on an enterprise-wide initiative to improve collaboration across all phases of T&E. This paper provides an overview of the USAF aeropropulsion T&E capabilities and the way forward which are 1) an aligned T&E Enterprise using coordinated tactical and strategic goals, 2) a seamless T&E approach using independent Air Force assessments, 3) state-of-the-art T&E capabilities capable of testing current and future generation propulsion systems, and 4) improved propulsion acquisition and development processes. This paper includes a discussion of past difficulties and successes and focuses on the approach employed to realize USAF goals.

scholarly journals Test and Evaluation of Shale Derived Jet Fuel by the United States Air Force

1985 ◽  
Author(s):  
C. L. Delaney
Keyword(s):  
United States ◽  
Air Force ◽  
Energy Security ◽  
United States Air Force ◽  
The United States ◽  
Jet Fuel ◽  
Quality Assurance Program ◽  
Synthetic Fuels ◽  
Synthetic Fuel ◽  
Test And Evaluation

In June 1980, the United States Congress passed the Energy Security Act which provided for the formation of the United States Synthetic Fuels Corporation and amended the Defense Production Act of 1950 to provide for synthetic fuels for the Department of Defense (DOD). A subsequent law, P.L., 96-304, appropriated up to $20 billion for financial incentives to foster a national synthetic fuel industry. The initial synthetic fuel project funded under the Energy Security Act is the Unocal Parachute Creek Project in Colorado with an expected shale oil production of 10,000 bbls/day. The Defense Fuel Supply Center (DFSC) contracted with Gary Energy Refining Company, Fruita, Colorado to provide approximately 5000 bbls/day of shale JP-4 for the United States Air Force (USAF) using crude from the Parachute Creek project, with initial deliveries to begin in 1985. The USAF immediately accelerated preparations for the eventual operational use of shale derived fuels for turbine engine aircraft. An extensive test and evaluation program was initiated consisting of aviation turbine fuel processing, fuel characterization, aircraft component and subsystem testing, engine and flight testing. This paper describes the testing program that was accomplished, the significant results which were determined and the quality assurance program that is being implemented to assure that the shale fuel meets the requirements of JP-4, the standard USAF jet fuel.

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.

Timely Application of Advanced Human Factors Test and Evaluation Techniques during the Acquisition of New Air Force Systems

1983 ◽  
Vol 27 (7) ◽  
pp. 581-583
Author(s):  
Michael L. Frazier
Keyword(s):  
Human Factors ◽  
Air Force ◽  
Human Performance ◽  
Performance Criteria ◽  
Test And Evaluation ◽  
Proposed Model ◽  
Force Systems ◽  
High Level ◽  
Advanced System ◽  
Evaluation Techniques

To ensure that all major Air Force systems are subject to adequate human factors examination, the dependence on data-free critical analysis concerning system (and human) performance should be kept to a minimum during testing. Human factors test and evaluators (T&Eers) require the timely application of state-of-the-art (SOA) test and evaluation (T&E) techologies to keep pace with advanced system design. The Air Force needs to establish high-level policies directing human factors technology to ensure there are: 1) SOA T&E procedures, models and techniques; 2) appropriate human performance criteria; 3) current specifications, standards and handbooks; 4) qualified and trained T&Eers 5) SOA T&E instrumentation and equipment, and 6) SOA T&E software. A proposed model for transfer of human factors technologies for test and evaluation is presented.

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