Evolution of Systems Engineering Methods - Engineering design methods evolved as the complexity of products increased due to the opportunities for more complex products that arose as new technologies and production methods became available. The developments of electronics in the mid-20th century and computers in the late 20th century were major drivers for increasing product complexity and causing the need for more and more sophisticated engineering design methodologies. The concurrent growth of more efficient production methodologies enabled the more complex products to be affordable. A brief review of this history and some of the noted chief engineers is helpful in understanding the modern methodologies. (Today we would call these individuals system engineers but that term didn't appear until the late 1950s or early 1960s.)
Chief Engineer Era - Before the middle of the 20th century products were relatively simple and large design margins were often used, which facilitated simple engineering methodologies. The principle engineering method was a chief engineer plus some assistants. This model is called the “craftsman” model because it’s like the methods an individual craftsman uses in developing a new product. Let's look at one example. Gordon M. Buehrig was a noted automobile designer from the 1930s to the 1950s. In 1935 the Cord Automobile Company was in trouble and needed a new design. Buehrig and his team developed the Cord 810, shown in Figure 2-1, in about six months, if my memory is correct.
Figure 2-1The innovative Cord 810 developed by chief designer Gordon Buehrig and his small team in just a few months in 1935. Photo Courtesy of Auburn Cord Duesenberg Automobile Museum, Auburn, Indiana
The Cord 810 was the first American front-wheel drive car with independent front suspension. The design had numerous innovations including hidden door hinges; rear hinged hood, disappearing headlights, concealed fuel filler door, semi-automatic transmission in front of the engine, variable-speed windshield wipers and a radio as a standard feature. The Cord 810 was a sensation at the New York Automobile Show in November of 1935 with Cord having rushed to build the 100 cars needed to qualify for entry. This rapid design and initial production temporarily saved the company. The design was recognized for its innovation by the New York City Museum of Modern Art in 1951.
Can you imagine a modern car company designing and producing 100 new cars with many new and even radical design innovations in about six months? Visiting Buehrig and his team's offices preserved in the Cord Museum provides some clues to how it was accomplished. The small team occupied a room with just enough space for the designers and their drafting boards. Buehrig's office was adjacent with only a glass window and doorway separating the two spaces. He was able to see every team member with a single glance and he could be at the side of anyone within a few seconds. This co-location enabled Buehrig to see all of the design information almost instantly and to ask questions and get answers almost instantly. Thus within the design team there was almost no information latency, that is the time between when information is available and when it gets to the individuals that need it for the next steps in their work.
The team was located in the same building as the top management of Cord and the factory was next to the office space and reachable within a minute. If Buehrig's team needed information about production capabilities or a decision from top management they could get the answers needed within minutes or a few hours at most. Of course I don’t know how it really worked in practice but the physical space where this team worked was organized for minimizing information latency and this is the lesson we should take from this story.
A second important contributing factor is the fact that cars were much simpler in the 1930s and a chief designer with Buehrig's talent could understand all the important design criteria and the merits of the design options available to his team, as well as the production capabilities of the factory. This enabled the team to be limited to a few designer/draftsmen and facilitated the speed of information flow. Today’s automobiles are too complex to be developed with such small teams.
Was the rapid design of the Cord 810 an anomaly? No, I could recite many such cases, particularly during WW II and immediately afterward. Many of my stories are about airplane developments since I worked in the aerospace industry. Most people have heard of Lockheed's famous chief designer Kelly Johnson and the Skunk Works.
Kelly Johnson was involved in the development of about 20 airplanes, including the famous P-38, U-2 and SR-71. Skunk Works has become the buzz word for organizations and facilities intended for rapid product development. Johnson's methods are well worth studying and applying today, although it is necessary to take into account the impact of modern computer technology on information flow. I’ll quote just one of his 14 Rules of Management here. Number 3 is “The number of people having any connection with the project must be restricted in an almost vicious manner. Use a small number of good people (10% to 25% compared to the so-called normal systems).”
Alexander Kartveli of Republic Aviation is another outstanding chief designer from the 1940s and 1950s with many firsts to his credit; including the first in-flight refueling, first supersonic fighter, first internal bomb bay and first “black box” fighter. His P-47 design, one of the top three US WW II fighter planes was on the drawing board in 1940, Ordered in September of 1940, in production in early 1942 and in service in 1943.
Rather than recite more stories of famous chief engineers I will discuss some principles from a company manual that I had the opportunity to read nearly 30 years ago. I won't give the name of the company as some of the material could still be proprietary.
The company had a grand history of successful and rapid airplane developments. Someone incorporated the “lessons learned” into a manual that was both a history and a compendium of principles for rapid development. The airplane factories from WW II that I have visited had long linear production lines with shops and offices along each side and on mezzanines overlooking the production lines. Thus for a development project where the goal was to build the first flight model it was possible to locate the team in a common space within sight of the area where the plane was being assembled. I'll recite only two of the lessons learned from the manual I read. One was that the engineering team was to be located in sight of the plane and where they could get up and in a few seconds inspect the hardware they were developing. Second, the team was to be co-located in a high walled space so that the progress of each sub-team could be plotted on a large schedule chart and posted high on a wall where everyone could see the progress of each team.
Again we see the attention paid to minimizing information latency. An engineer that had questions about some part of the plane could quickly look at the hardware, if that would yield the answer. Everyone could see each other and if an engineer needed information from another engineer or even from another team it took only seconds to walk to the work space of the engineer with the answers. Posting the progress of each design team so that it was visible to all the teams had two positive impacts. First, there was the peer pressure to not be the team that was holding up progress. Experience had shown that a team that was behind would find ways to catch up with little or no management intervention. Second, the chief designer could concentrate on technical issues rather than managing schedule issues.
From the automobile design example cited above and the principles used for rapid development of airplane designs we see that the pressure for getting products to market fast are not unique to the 21st century. Twentieth century engineering methodologies adapted to this pressure by organizing and locating engineering teams to minimize information latency. The “craftsman” model of a chief designer plus some assistants worked well because the products were relatively simple and often large design margins were acceptable. The low complexity of the products enabled the chief designer to understand all that was necessary to achieve a balanced design that was manufacturable at acceptable cost. Thus the design process was what we now call a concurrent process; the chief designer knew the manufacturing capabilities and designed to conform to these capabilities. These conditions for product development were no longer true by the 1950s as product complexity had increased so much that engineering specialists were needed and new methods required to manage the larger engineering teams that resulted from adding the specialists. These new methods are defined in the next post.
No comments:
Post a Comment