Page:Collier's New Encyclopedia v. 06.djvu/390

MOTOR VEHICLE 328 MOTOR VEHICLE of almost eveiy conceivable type of com- modity, from jewelry to pig iron. Special dumping trucks for handling building materials, coal, etc., are used. During the World War the United States Govern- ment adopted two standard types of AUTOMOBILE UNIVERSAL JOINT truck, a light-weight model and a heavy- weight model, for army use. These trucks, called Liberty trucks, were designed by representatives of the leading truck manufacturers of the United States, who incorporated in their design every de- sirable and successful feature which had been developed by any individual manufacturer. Because of the standard- ization, quantity production was soon reached, and the army amply provided with trucks. The modern pleasure car varies in type from the car which is manufactured on a quantity basis, standard parts for which can be purchased at almost every crossroad, since it is a custom-built car in which the owner decided almost every detail. The mechanical details of the then superheated by a device of some sort, after which it is conducted to a compound reversing engine. The exhaust steam is then frequently condensed and injected again into the boiler. Gasoline vapor is the fuel most frequently used to generate heat. The big advantage of the steam motor vehicle was the absence of gears which resulted in flexibility of speed and quiet- ness of operation, while its drawbacks were the open flame needed to generate steam, the time required to get up steam before a start could be made, the small cruising radius on one filling of the water tank, and the complication of the fuel- regulating devices. Among the first motor vehicles were those which used an electric motor for propulsion. The power is supplied from a storage battery, and in many of the early types there was a motor for each rear wheel, a switch to reverse the di- rection of the current, and a rheostat to control the speed of the motor. In the more modern types a single motor drives a shaft, and there is a geared trans- mission. The great drawback ^ for the electric vehicle is its short cruising ra- BEVEL DIFFERENTIAL GEAR motor vehicle are considered under these headings: 1. The motive power. 2. All other parts of the chassis except the motor — the frame, springs, transmission, and wheels. In the steam-driven motor vehicle, steam is often generated in a flash boiler, ROADSTER dius. Although many improvements have been made in storage-battery construc- tion in the last two years, still the only way to increase the radius is to add cells to the storage battery, which of course, increases the weight. In order to re- charge the battery a special apparatus is needed. The introduction of the elec- tric self-starter for cars using an inter- nal-combustion engine has done much to nullify the claim that the electric car was the only car for a woman to drive, and the popularity of the electric pas- senger vehicle has decreased in recent years. The electric truck is successfully used for comparatively short hauls over level pavements, being particularly adapted for city delivery work or for service around dock and terminal sys- tems. The four-cycle gasoline internal-com- bustion engine is the standard means of motor-vehicle propulsion to-day. The internal-combustion engine has the ad- vantage of light weight for its power. It is a safe source of power; the motor