IN this paper the authors present some experimental results obtained by using the analysis outlined by Prof. James J. Guest before the Institution of Automobile Engineers, in 1926. To make the experimental work more understandable, they present the essential points of Professor Guest's analysis.
Professor Guest begins his analysis of the movements of a car body with the simplest set of conditions and presents a graphical as well as an algebraic solution. He then includes one additional factor after another in his analysis until the principal factors in car suspension are included. After all factors are considered, the essential structure of the simple analysis is retained.
The authors' efforts at the experimental determination of the moment of inertia of passenger cars were started in January, 1932, on Sir Charles Dennistoun Burney's “tear-drop” design with which he visited leading American manufacturers. The first of the series of experiments was made by jouncing the car alternately about the front and rear axles. The front springs were blocked rigidly and the car jounced on the rear springs to obtain the period of the horizontal pendulum thus created. A further series of tests was made on a small laboratory set-up.
The foregoing and other check tests are described in detail and the results commented upon. The development of the formula used in calculating the moments of inertia obtained experimentally with a horizontal compound pendulum is given, further to clarify the method described.
In conclusion, the authors state that it is not possible to draw any definite conclusions from the work described, but they feel that the analysis presented by Professor Guest has made it possible to visualize clearly many of the problems connected with vehicle springing.