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Believing that a knowledge of definite, quantitative relations affecting the behavior of vehicle suspensions will lead to a better understanding of the problems of spring design, the author analyses the problem by considering it as a simple system (a single wheel supporting a weight by means of a frictionless spring), and by assuming that this system encounters certain elementary forms of irregularities. Analysis of this problem results in several expressions, the interpreting of which reveals the influence which the varying of specific factors has upon the action of the spring and its suspended load. These expressions take into account the effect of the ratio between sprung and unsprung weight, of speed, of size and kind of irregularity encountered by the wheel, tire inflation, flexibility of the spring, and wheel diameter. Other factors which are considered as a result of interpreting the curves presented are the effect of friction in the suspension, and of synchronism.

The author considers the effects of velocity variation on the operation of a car and states that this variation is absorbed mainly by the flywheel. A formula is given for calculating the pressure on universal bearings. Various methods of protecting and lubricating joints are described. A number of European types of joints are illustrated. A much larger number of types of joints are used abroad in-asmuch as each maker usually makes his own design instead of purchasing it from a specialist as is the usual practice in this country. In conclusion the paper describes types of joints using flexible material, such as leather or spring steel.

The author outlines in a general way the relation of car performance to modern engine development. He considers particularly weight reduction and torque performance of high-speed engines, giving the undesirable characteristics attending the increased torque range gained by higher speed. He next discusses the relation of torque to total car weight, to acceleration and to hill-climbing ability and suggests a method of determining the value of a car in terms of its performance ability. The author holds incorrect those systems in which the amount of lubrication is in proportion to speed only; and in which oil for crankshaft and crankpin bearings must cool as well as lubricate them. He shows a system designed to solve these oiling problems. Static, running and distortion balance of a rotating mass are defined by the author, who shows how they apply to a large number of types of crankshafts.

The author gives a brief review of developments during the past year in the construction of aeroplanes, particularly as affected by the European War. He takes as an example the Renault twelve-cylinder engine, citing the respects in which the present differs from previous models. Such factors as the changes in cooling systems, method of drive, valve construction and starting devices are considered. The requirements of aeroplane engines, such as constant service, high speeds (of aeroplanes) and stream-line form of engines and radiators, are outlined. Propeller requirements are dealt with at length, curves being given by which the efficiency and diameter of the propeller can be obtained. In conclusion a number of different engine installations are illustrated and compared.

Substitutes for the conventional type of differential are considered under four classifications; namely, the free-wheel type, the crank and eccentric types, the spiral gear type, and the solid axle. Examples of each of these classifications are described and the advantages and disadvantages of some of the more practical ones discussed. Considerable space is devoted to a discussion of the elimination of any form of differential whatever. Although such construction has advantages of eliminating the spinning of the wheels and assuring positive travel under all conditions, the author believes the disadvantages too great to be overcome. The paper mentions some interesting experiments conducted by street railway engineers in connection with using differentials for street cars, to eliminate the corrugation of rails and wheels, as well as to economize in power consumption.

This paper is mainly an argument in favor of the use of large, single rear wheel truck tires instead of smaller dual tires. Although the practice of using large singles is comparatively new, the author gives the results of experience and research to show the advantages of the newer method of rear tire equipment. In developing his arguments in favor of single tires, the author goes into the history of dual tire application to show why it was necessary to use two tires in the earlier days of truck operation. As the necessity for increased carrying-capacity grew, tire manufacturers found the then existing single tire equipment inadequate, and they set about to develop suitable equipment to meet the new condition, the result being dual practice. The method of attaching the earlier dual tires is shown to have been poor, resulting in circumferential creeping of the whole tire to a much greater extent as the width of the dual equipment increased.