BARNES, W., "Front-Axle Movements," SAE Technical Paper 290004, 1929, doi:10.4271/290004.
IN THIS paper, W. B. Barnes describes a device developed to give a graphical record of front-axle movements while the car is on the road. An analysis of these results reveals some startling facts concerning the amplitude and character of axle vibrations in various cars. When striking an obstruction or during brake application the axle as a whole may rotate forward as much as 5 deg., giving a negative value to the caster angle, which Mr. Barnes declares is utterly ruinous to any steering control. Furthermore, the instantaneous center of rotation may vary from a point near the level of the spring main-leaf to a point 4 or 5 in. above it.This paper was presented at the Chassis Conference at the Semi-Annual Meeting last June. The author supplements it with an explanation of the way in which certain of the principles developed in this research have been embodied in the design of the front-drive car announced by his organization since the presentation of the paper.