SOME practical examples of correct as well as of incorrect methods of designing are studied, using a motor vehicle for illustration. The mechanism of such a vehicle should be very simple, and the elimination of certain links and members here and there may become more or less desirable. It is essential to know how much this will burden other members, and what strengthening or even redesigning may become necessary.
It has been proposed to eliminate the torque and radius-rods. By formulas and drawings the author shows how complex the problem is and the various changes that must follow such an attempt. A vehicle must have much stiffer springs if the torque rod is to be eliminated. This inevitably leads to a study of springs and of the influences of brakes. A vehicle can be operated at somewhat higher speed with a torque-rod. Several printed statements and diagrams are cited to show that certain fundamental principles, apparently fairly well understood, are being overlooked by designing engineers.
There is also much misconception among designers regarding crankshaft bearing sizes and loads. Taking four cases for illustration, the various problems connected with bearing loads are worked out and diagrams prepared to show results. Several tables are given summarizing data in the text and in a comparison of results, “rule of thumb” information and other highly-esteemed authority are proved to be in error.