Fig. 12.-Plan View of Chassis when Radiator, Cooling Fan, and Muffler have Been Put in their Proper Places.

Fig. 13. The Finished Chassis as it Appears After the Front Wheels, Tires, Traction Wheels, Brake Drums, Running Boards and Finishing Touches Have Been Made.

ance after the change speed gear box has been fastened to the two center cross members is shown at D. It will be noted that the power plant is attached directly to the frame side members by means of arms or lugs extending from the engine base. These are firmly bolted to the frame sides and the motor bed forms a very strong member which serves to keep the two sides of the frame together.

The views at Fig. 10 show further steps in the process of making a motor car. At E, the motor fly wheel has been joined to the gear box by means of a clutch and driving coupling. At F, the rear axle has been bolted to the springs and the radius or distance rods have been installed.

At Fig. 11 the chassis begins to assume a more finished appearance. Referring to G, it will be seen that the gear box has been connected to the rear axle by means of a driving shaft which has a universal joint at each end. The torque rod, which is a member designed to resist braking and driving torque stresses and to maintain a fixed distance between gear box and rear axle, has been put in place. At H, the steering post, on which are placed the motor control levers and steering wheel, has been fastened to the frame side member and the steering mechanism has been joined to the front axle by the drag link. The gear shift and emergency brake levers have also been placed.

Inspection of Fig. 12 will show the radiator and cooling fan on the extreme front of the frame, almost directly over the front axle, and that the power plant has been joined to the radiator by a piece of rubber hose. The exhaust pipe and muffler have also been fitted.

The appearance of the complete chassis, ready to receive the body, is shown at Fig. 13. The parts added are clearly indicated. The front axle has been made complete by the addition of the wheels and tires. The rear construction has also been finished by supplying the traction wheels, tires, and brake drums. The brakes have been connected to the operating pedal and lever by rods; and step hangers, which support the running boards, have been riveted to the frame sides. The chassis, as shown at Fig. 13, is made a finished car by the addition of a suitable body, gasoline tank, sheet metal under-pan to protect the mechanism and mud guards which extend from both extremities of the running board to the front and rear, respectively, over the wheels to protect the body from mud thrown by the wheels.

Wind Resistance and Body Design.-The reader who studies closely modern motor-car design will see that the bodies which are popular at the present time are of different form than those which were formerly used. They are lower and have gradual curved sides. The object of this new construction, or torpedo body, as it is called, is to reduce wind resistance and also lessen the dust-raising proclivities of high speed automobiles. The effect of the air disturbed by a rapidly moving vehicle may be easily observed during the Fall when the weather is settled and the ground is well covered with leaves. When a car is driven along the road at moderate velocities a careful observer will detect movement of leaves fifteen or eighteen feet away from and at the side of the car. This shows that they have been affected by the large volume of air set in motion by the car body. It is obvious that dry dust would be disturbed in a similar manner, and if special attention was not directed toward reducing the air movement any motor car, even if moving at moderate speeds, would leave a cloud of dust in its wake.

Dust disturbance is not the most important factor, however, in determining body form, but it is the resistance of the air that is taken into consideration because of power absorbed. The object in designing should be to reduce end on resistance area to as low a point as possible, because the less area one has to push through the air, the less power it will take to overcome air resistance and more energy can be expended in driving the car.

At Fig. 14, the front view of a typical motor car is shown with dimensions which indicate the approximate size. To ascertain the total area, one or two points require consideration. The radiator, which is the largest member setting at a vertical plane, cannot be considered as offering an area that its overall dimensions would indicate. A large volume of air passes through it, but by no means all the air that passes between the tubes and the radiator discharges without resistance. Some of it flows easily around the power plant, and some streams out under the floor boards, especially if these are inclined. The greater part of the air which passes through the radiator must be deflected by the vertical dashboard which separates the motor compartment from the body, and the reaction due to this cause is comparable to the resistance which would obtain if the radiator was prac