Stamping Plant.—With the change from all-wood bodies to framed bodies panelled in sheet-metal, the stamping plants took on a big increase in work. Many parts formerly made of forgings or malleable castings are now made of stampings, reducing cost and weight. (See MOTOR CAR, Motor Car Body Design.) Assembling.—It is in all branches of assembling that the prog ress made in the industry is most striking. Whether it be a motor, axle, transmission or entire car, the assembling is done on a steadily moving conveyor, all parts being fed to this conveyor at the exact place and time needed. The routing and scheduling of the individual parts and sub-assemblies through the various plants or departments to arrive at the final assembly line on time and at the required rate is a nice problem in synchronization, as some of the primary operations must start weeks ahead.
Service.—Provision of repair parts for the owner has been given a great deal of attention for years, not only as to require ments but as to interchangeability. It is the aim of every manufacturer to have a part on hand when the owner wants it. The rapidly increasing number of cars in use and the constant changing of models has complicated the matter, but for those who have studied the question for years each year gives better data as to the life of various parts of the car. In this way the manufacturer can estimate closely what parts will be required for replacements, and plan production accordingly.
The Modern Road Testing.—In order to determine success fully the way in which an automobile will function in the hands of the average owner, motor car manufacturers have made a practice of conducting tests over a wide variety of road condi tions, and recording data as accurately as possible on the per formance over thousands of miles. Such tests must be carried on, as it is not possible to duplicate exactly tremendously varying road conditions, even with the most elaborate laboratory equip ment. It is not possible in a laboratory to reproduce the violent stresses to which a car is subjected in driving over frozen, rutted roads. Road testing naturally follows the detailed development work of the component parts of an automobile and provides a means of checking the final design to determine the character istics of comfort, performance, economy, reliability and dura bility. When such tests are conducted on the public highways, many variables must be taken into consideration, such as weather, condition of roads, traffic and legal regulations. As a result, delays frequently occur, and often the tests are a source of danger to other users of the highways. All of these factors have some effect
upon the accuracy of the tests and the speed with which the information may be obtained. Consequently, manufacturers have utilized such facilities as may be available where carefully con trolled tests may be made.
The need for these better controls has increased quite steadily as refinements in car design have become more exact. At one time, racing provided a good means for such tests, but in recent times manufacturers have turned to more regularized means of checking the performance of their cars. Several American motor car companies, in order to provide standardized conditions for tests, have installed private testing grounds containing a wide variety of roads where many conditions can be maintained con stant and so designed that motor cars may be operated day and night at all times of the year. Such a road system includes high ways where sustained high speed may be maintained with safety, concrete hills with accurately laid gradients, level stretches to insure elimination of error in critical engineering tests,—in fact, a duplicate of nearly every type of road found among the public highways. Other manufacturers have utilized chiefly the high-speed track. One company in Italy has gone so far as to incorporate this track on the roof of its factory building. Under such standardized conditions, cars may be tested and the results compared from "day to day and year to year with reasonable accuracy.
The private testing ground offers many advantages over the public highways, in that traffic conditions can be controlled defi nitely and the information obtained on the tests is more quickly available to the designers. Even though the test car travels r,000 m. or more a day, in the event of failure of any part, it is still only a few minutes away from the shop and the engineer. Again, such a testing ground as a part of the automobile manufacturer's facilities permits the establishment of definite standards of per formance, comfort, economy, reliability, etc. It permits the man ufacturer to operate his experimental design simultaneously and under the same conditions with any other cars with which he wishes to compare for speed, acceleration, braking, riding quali ties, or anything else of importance to the customer. Thus the designer is able to set up a continually improving set of specifi cations based upon the hitherto intangible operating differences between various cars.