Earll M. Murman

Total pressure loss in vortical solutions of the conical Euler equations

A technique for the solution of the conically self-similar form of the Euler equations is described. Solutions for the flow past a flat-plate delta wing at angle of attack are presented. These solutions show strong leading edge vortices with large total pressure losses in the cores. A study of the effects of various computational parameters on the total pressure loss is made. An explanation for the cause of the total pressure loss is presented. It is shown to be consistent with the results for both a quasi-one-dimensional model problem and the conically self-similar flow past the flat-plate delta wing.

Lean engineering: a framework for doing the right thing right

Lean techniques are having a major impact on aerospace manufacturing. However, the cost and value of aerospace (and many other) products is determined primarily in product development. Migrating lean to engineering processes is ongoing in the industry, and a subject of study at the MIT Lean Aerospace Initiative. This paper summarises findings to date, with references to both research literature and successful implementation examples. To implement lean engineering, a three-part approach is needed: Creating the right products, with effective lifecycle and enterprise integration, using efficient engineering processes.

Leading-edge vortex solutions with large total pressure losses

Computations are presented for a Lambda = 75 deg delta wing in a supersonic freestream under two conditions which lead to leading-edge vortices. For one condition, analysis of the computed vortical flow reveals a closed streamline in the core. From varying computational parameters, it appears that this is due to truncation error of the convective derivatives. For the other condition, comparisons are made with wind-tunnel data, and good agreement is noted for pitot pressure distributions, flow angles on the symmetry plane, and the position of an embedded shock. Many of the aerodynamic parameters are shown to be insensitive to grid spacing.

Improving The Software Upgrade Value Stream

*† This paper reports findings from a two-year study to identify Lean practices for deriving software requirements from aerospace system level requirements, with a goal towards improving the software upgrade value stream. The study was undertaken as part of the MIT Lean Aerospace Initiative. Three detailed case studies and 128 surveys collected from ten “successful” mission critical aerospace software upgrade programs support seven major findings. I. Background The Lean Aerospace Initiative (LAI) is a government, industry, labor, and academic consortium focused on identifying and implementing the principles of Lean in the aerospace industry. Lean originated in the automotive industry and is grounded in the manufacturing domain. To the authors’ knowledge, this is the first research specifically designed to apply the Lean principles and the Lean Enterprise Model to the process of deriving aerospace software requirements. The basic principles of Lean are focused on employing value added activities to reduce product cycle time, increase quality, reduce cost, and increase stakeholder satisfaction. Deriving software requirements are an important step in developing aerospace software products. Requirement derivation activities occur early in the product development process and can have significant impacts on the cost, schedule, and performance of the system 3 . The cost to correct errors made early in the phases of product development grows exponentially the longer they go undetected 4 . Analyzing the requirement process using a Lean framework allows practitioners the opportunity to improve the process to reduce the possibility of adverse system impacts. The Lean Enterprise Model (LEM) 5 is a framework that incorporates enterprise level lean principles and practices, together with supporting data. This research utilized the LEM framework to identify the presence of Lean practices in the process of deriving software requirements on real time mission critical aerospace systems. LEM enterprise level metrics (Flow Time, Stakeholder Satisfaction, Quality Yield, and Resource Utilization) were used to develop process outcome measures. The twelve Overarching Practices identified in the LEM 5 were used as a guide for analyzing the presence of effective Lean practices for deriving software requirements. The findings identified in this paper are the product of a comprehensive two-year research effort 1,2 involving three detailed case studies consisting of 45 interviews, in support of 128 stakeholder surveys collected from 10 aerospace systems, feedback from numerous aerospace industry practitioners, and Massachusetts Institute of Technology faculty and students. All 10 aerospace systems were real-time mission critical software upgrades representing four application domains (military aircraft, military space ground terminal, commercial aircraft, and missile/munitions). LAI industry and government consortium members selected the systems involved in the research effort. Each system is believed to be one that had a successful derivation of software requirements. Table 1 summarizes some of the discriminatory characteristics of the systems used in the research.

Islands of Success

The journey to lean for the US Aerospace Enterprise began in earnest in the early 1990s, as industry and government responded to post-Cold War imperatives. Most organizations responded first by harvesting the ‘low-hanging fruit’ — opportunities that required minimum investment and that would yield quick results. Often, these resided on the factory floor, where it was felt that rapid improvements in production processes could be implemented. To be sure, there were some more far-reaching change initiatives — ‘pilot projects’ — where a measured industry or government investment could show progress and serve as a powerful illustration of new principles and practices. But going after the ‘low-hanging fruit’ was most common.

The LAI Lean Academy Experience: Introductory Lean Curriculum

This article reports on a decade-long undertaking to develop and widely deploy an introductory Lean curriculum. The origins, objectives, and history of the effort are summarized, as is the content of the core 3-day short course. Versions of the curriculum have been offered to over 1,600 participants in 60 short course and semester-long subjects taught by 45 different instructors in the United States and Latin America. Over 270,000 visits have been made to the curriculum posted on MITs Open Courseware. Findings on the learning outcomes are presented based upon the extensive database complied from student feedback and self-assessment.

Visualization of three-dimensional CFD solutions

The implementation is described of the FLOWVIS flow visualization package on a graphics supercomputer that provides real-time interactive investigation of three-dimensional CFD solutions on structured and unstructured meshes. The data structures are briefly described and the methods of visualizing flow fields are examined, including surface plots, particle paths, and planar displays in the flow field. Preliminary results using the package and work in progress are discussed. 9 references.

The 21st-Century Enterprise Challenge

The core challenge for industries in the 21st century involves identifying and delivering value to every stakeholder. Meeting that challenge requires lean capability at the enterprise level.

A Value-Creation Framework

Successful enterprises must not only do the job right: they must do the right job. Becoming lean, as traditionally defined, is important, but it is only part of the story. More important is to use lean concepts and approaches to create value for all stakeholders for all enterprise missions. That’s the essence of our Chapter 1 principles.

The Cold War Legacy

From its modest beginnings at Kitty Hawk — and even earlier, in da Vinci’s sketches — the urge to defy gravity inspired what has since become the aerospace field. And from that moment when we were able to fly, humans have sought to go higher, faster, and farther. This quest was never more manifest than during the decades after World War II, as US national defense and prestige, along with increasing demands for transporting people and goods, drove tremendous growth in the US Aerospace Enterprise — that national community of aerospace firms, US government executive agencies and departments, Congressional committees, professional organizations, universities, and labor unions.