Although off-topic, I found this to be interesting reading for anyone interested in the engineering aspects of designing a product. The following are excerpts from one chapter in the book: "Invention by Design - How Engineers Get from Thought to Thing" By Henry Petroski ISBN 0-674-46368-4 Designing a model plane is pretty small task in comparison with designing a jet aircraft. Design of a Commercial Aircraft In the 1950's an airplane like the 707 cost about 15$ million to develop and test; by the mid-1980's designing and developing a totally new airplane was expected to take billions of dollars, thus risking the very life of the company on the venture. The traditional way of carrying out the detailed design of a new aircraft was for a lot of engineers and draftspersons to work individually and in teams on various parts and subsystems of the plane. In the 777 there were over 130,000 unique individual parts to be engineered and, when rivets and other fasteners are counted, over 3 million total parts to be assembled into each plane. The 747, which had a total of 4.5 million parts, required about 75,000 individual engineering drawings to specify. To check that parts and systems were compatible, an engineer working on one part had to get the drawings of mating parts, and any change that might have to be made in one area necessarily had sometimes fundamental implications for other parts or systems. It was a slow, arduous, and frustrating process, and one senior draftsperson at Boeing recalled "waiting for days to get someone else's drawing, getting a copy made, and slipping it under mine to trace their part." Another big problem associated with coordinating a great number of individual parts was that when it came time finally to assemble the actual airplanes, not everything fit exactly. Shims of one kind or another had to be inserted to smooth out the poor match of fuselage parts, even though they had been manufactured according to specifications. For example, the 747 contained about 1000 pounds of shims. Computer-Aided Design To design the 777 as efficiently and cost-effectively as possible, while at the same time achieving high quality, Boeing chose a "paperless" design strategy. Boeing's earlier limited experience with computer-aided design consisted of designing an engine strut for the 767. That design was completed 3 ½ months ahead of an allocated 24 months, and at a cost that was lower than estimated for then-conventional design methods. As many as 238 teams, comprising as many as 40 engineers, were involved in the design, development, and manufacturing of the 777, and they all needed access to all of the computer data. A truly paperless design meant that, instead of waiting for physical drawings to be copied and checked for compatibility of parts and systems, an engineer working on a single part could call up all mating parts or systems into which it was to fit on any one of the over 7000 workstations that were eventually spread around the world in over 17 time zones. The Skunk Works Before the advent of CAD and CAM and the ease of communication they have allowed between design and manufacturing engineers, in most technological enterprises the drawings for individual parts were said to be "thrown over the wall" separating the design from the manufacturing teams, with the sometimes overly optimistic expectation hope that the part could be in fact be mated with other parts. There had been a few notable exceptions to this short-sighted practice, and one was the division of Lockheed known as the Skunk Works, where design engineers worked in the same building in which their highly classified designs were assembled. The Skunk Works was responsible for such supersecret and technically supersuccessful projects as the U-2 spy plane and the F-117A stealth fighter. RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
