Tham khảo tài liệu 'aircraft design - systhesis anh analysis 2008 part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | delayed for many years. Two years after the B-747 production engineering began Douglas and Lockheed started projects about 2 3 the size of the B-747. originally built for domestic service the Douglas DC-10 was soon extended to the range of the 747 but with a smaller size. On many routes 360 passenger airplanes are too large. On may routes 360 passenger airplanes are too large. After the Lockheed L-1011 the Douglas DC-10 were offered the re-orders for the 747 were being greatly reduced. The situation for Boeing was aggravated by the fact that the economic recession in 1970-71 reduced travel growth for both business and pleasure. In 1973 the future of the 747 seemed a little indefinite and Boeing s financial situation was poor. By 1975 the economic recovery was followed by an air traffic resurgence and B-747 orders improved. Then reduced fares stimulated a large air travel increase and 747 orders grew to a high level that insured that the project will be profitable. But Boeing faced a few years of very low production when the airlines found the smaller airplanes more suitable. The B-747 was too big too soon. Another example of a timing error is the Boeing 737. By the time Boeing decided to build the 737 over half of the market had been taken by Douglas and 10 by the British BAC 111. Still another example is the Lockheed 1649 which was a long range version of the famous Constellation. TWA forced Lockheed into the design a major change from the basic Constellation in order to compete with the Douglas DC7C. Only about 40 of them were sold and a great deal of money must have been lost on that project. Timing is one of the very important factors. Related to timing is the important matter of competition. The overall market may be strong and a great airplane design may be under consideration. However if there are two other companies six months or a year ahead of you with many of the major airlines having already spoken for their airplane you may be finished before you .
