IN this paper, the authors have made no mention of the various types of brakes used in any of the tests, and have endeavored to avoid partiality to any particular type of brake drum or lining, as each fills a particular need which can only be determined by the individual requirements of each car manufacturer.
Brake drums and brake lining must be considered together in present-day brake engineering. The manufacturers of both products have found it necessary to carry on extensive development programs in order to improve the performance of their respective products.
Test results should not be a matter of opinion, or subject to a wide variation in the personal equation. Therefore, this paper is devoted to a general description of the latest inertia-type brake-drum-and-lining testing-dynamometers, giving illustrations of both machines and descriptions of the functions of the various attachments, followed by an outline of the general methods at present in vogue for their use.
No attempt has been made to present actual test-data, and a general discussion is given regarding the use of the machines at present. The discussion leads to but one conclusion-the necessity for exact and thorough evaluation in order that the performance characteristics of drums and lining can be definitely established and classified.
This can only be brought about by the development and use of special laboratory equipment such as is described, which can be relied upon to give consistent data, eliminating the human element and other variables which enter into the various methods of road testing.