What Engineers Know and How They Know It: Analytical Studies from Aeronautical History

by Walter G. Vincenti

Book Overview

To solve their design problems engineers draw in a vast body of knowledge about how things work. This problem-solving knowledge may appear mundane or derivative from science, but in What Engineers Know and How They Know It Walter G. Vincenti shows how sophisticated and "internal" to engineering it really is-and how seemingly simple design requirements can have complex intellectual implications. Examining previously unstudied historical cases,...

• Format: Hardcover
• Language: English
• ISBN: 0801839742
• ISBN13: 9780801839740
• Release Date: September 1990
• Publisher: Johns Hopkins University Press
• Length: 326 Pages
• Weight: 1.55 lbs.
• Dimensions: 1.1" x 6.3" x 9.3"

Customer Reviews

interesting chapters from aeronautical history

As Prof. Vincenti points out in the preface, the people interested in the history of aviation may prefer to omit epistemological parts of the book. I must agree. The epistemological part (introduction of the book, introductions and conclusions of the chapters, 50 pages after the chapter 6) is too wordy to my taste. I can't say it isn't interesting (based on what I learned about differences between engineers and scientists I can say that I am engineer) but it is definitely not easy to read (with lot of redundancy and abstraction). The narrative part of the chapters 2-6 is other case. There are very interesting stories about: 2. airfoil design and use (laminar flow, Davis's airfoil used in B-24 Liberator) 3. flying quality specification 4. development of control volume analysis (in Prandtl's aerodynamics) 5. air-propeller test (by Durand and Lesley) 6. development of flush riveting The notes in pages 259-318 contain also comprehensive bibliography to all stories.

a glimpse into engineering information gathering and use

One commonly held view of the relationship between scientists and engineers assumes that the latter represent an applied form of the former. Vincenti shatters this notion by showing how engineers develop their knowledge and use that information in the context of the problems they solve. While engineers and scientists share in their formative education a curriculum heavily devoted to mathematics (at least through differential equations) and fundamental physical forces, their priorities diverge at the context of their assigned tasks and in the type and quality of information that can be made available to complete their purposes. In particular, engineering knowledge does not exist for its own sake, in contrast to science. Vincenti cites several examples from the aeronautics industry. While these descriptions take on an anecdotal character, these collected narratives nonetheless impose his conclusion as well as any philosophical essay could and probably better. In each case, _What_Do_Engineers_Know_?_ demonstrates that incomplete information may yield intermediate results having little or no effect on the intended problem. The first example relates to a wing design for the B-24. The history of the Davis airfoil design is explained, as well as its incorporation for the B-24 wing. At the time of its adoption, various airfoil shapes had been investigated, and the Davis form subsequently was found to resemble the high performance laminar-flow airfoil. But did this form benefit the B-24 performance. Probably not, answers the author. Laminar flow can be difficult to maintain at the Reynolds numbers typical of modern aircraft, particularly in wartime conditions when surface roughness will likely increase tripping the boundary layer to turbulent (with resulting increased drag -- laminar flow has a thinner boundary layer, but is more prone to flow separation). The B-24 was considered a fine aircraft, in part due to its wing length.The second example describes flying-quality characteristics and relative design priorities regarding stability and control. (The Wright brothers had emphasized stability in the infancy of manned powered flight.) Designers had to determine what characteristics made an airplane desirable to pilots, and which would consign them to the scrapyard. This ergonomic study evolved as pilot and aircraft capabilities expanded in speed and flight duration. An appendix provides qualitative criteria used to compare stability performance. The third example compares how thermodynamics is treated by physicists and engineers. The latter employ control volume analysis as developed by Ludwig Prandtl for economy and accuracy rather than the understanding of nature governing thermal energy transfer. The fourth example covers data collection for airplane propellers. Subtle changes in camber, pitch and twist in a design can have subtle or profound effects on efficiency. These were evaluated using empirical studies, in contrast to a mor

Vincenti shows the way technologies mature

I am an instructional technologist dealing a lot with the design and development of products in a young technology, computer-based instruction. My technology is in its youth compared to other technologies that have become essential to our social and economic operations. I am interested in knowing the stages my technology will go through and the types of knowledge it must accumulate as it matures, which seems certain, given current interest and ferment.Vincenti describes how aeronautics technologies grew and went through their stages, and this has given me insight into my own. This is not a book of idealized process for implementing technology. It is s set of historical case studies, some of which Vincenti himself participated in, others of which he researched.The book is not easy to read, but I have found it very rewarding. It is full of technical terms and heavy technology. At the same time, if you pay the price in effort and study this book carefully, you will not be disappointed. You will see how technologies develop, and knowing this, you will be able to anticipate developments and needs in your own area of growth.