Frederick A. Draper

The design of the runabout to be described in this series of articles is as simple in construction as a serv-icable vehicle will permit, and the work will not be found difficult by anyone having reasonable skill in the use of a screw-cutting lathe. With the exception tion of the balance wheel on the engine, all the machine work can be done on a 9-inch lathe, this being a

Figure 1. Side View.

size in common use among amateur mechanics. It is quite probable that, of those making a car from this description, some will prefer to buy complete parts, such as the engine, in preference to making them. therefore the several chapters will be progressively arranged with this in view, the frame and running gear being first described, the engine being taken up last. As will be noted from the illustrations, an air-cooled gasoline engine, E, is the motive power, one with a 3 1/2 in. cylinder at 1200 to 1600 rev. per min., providing suf-ficient power for all except a very hilly country. If greater speed and power is thought desirable, a slightly larger engine can be used; it may also be water: cooled if the maker prefers that type, as there is plenty of room in the hood for radiator tubes, gasoline tank and a tool box of ample capacity.

As one of the requirements of this car is as low a cost as possible, wire-spoked wheels with wood rims are used, although cost was not the sole reason for adopting this kind of wheel. It can, in case of an accident, be easily repaired at about any bicycle repair shop, and at small cost : whereas a wooden wheel, when out of order, requires a skilled wheelwright to repair it. The rims are cresent shape.

The tire question is of decided importance, and, after considering all the advantages of the various types, the single tube, 28 x 2 1/2 in., was selected as being most suitable. A 2 in. tire can be used, but the saving in first cost would soon be offset by renewals, the smaller tire having comparatively thin walls, and not heavy enough for continuous work. In addition, the difference in first cost between the two sizes is not very great, and the larger size is enough more durable to warrant the extra expense.

Figure 2. Plan of Amateur Runabout.

In addition to the brake on the differential, drum brakes are shown on the rear wheels. The latter are necessary only in the event of the car being used in a rather hilly country, and plenty of power desired for holding on steep grades.

A wheel steering device is shown, but a lever may be substituted, and is quite sufficient for such a light car. Whichever form is used, the driver should at all times keep it in the control of the hand ; carelessness in this regard being responsible for many avoidable accidents.

The change-speed case G, expansion clutch C, and a few other parts, have been designed especially for this car. Two speeds forward, 6 and 24 miles, and a reverse, are quite sufficient for a car of this size, and by omitting one forward change (three changes being the usual number) a much lighter and more easily made gear-case is obtained. On the high speed no gears are in mesh, the drive being direct. Ample lubrication is also provided. Castings for the special parts are being prepared, and can be purchased at very reasonable price. The expansion clutch is of the metal-to-metal type, very similar to one described in a recent issue of this magazine.

The front axle is of the usual type with forged steering knuckles for ball bearing hubs. The pivots should also be forgings. The rear axle is of the " live" type, with differential and sprocket enclosed in a muff, to which is attached the axle casing. The hubs of the rear wheels are keyed in.

The frame for the body is of angle iron with cross ties of the same, which gives a rigid yet light construction. The springs shown, four leaf, 32 x 1 1/4 in., are the double eliptic, but 3/4 eliptic springs with suitable hang-ers can be used if preferred, but are more expensive. It will be noted that the engine, the heaviest single part of the car, is placed on the side opposite the driver, thus serving to balance the car when carrying only one, who is generally the heavier when two are riding. It will also be noted that provision is made for having the top of the rear part of the body hinged to fold back on itself, and fitted with a seat and light frame back support, thus allowing children to be carried, which can be done on level roads. When not so used, ample space is provided for luggage needed on a long trip.

The body can easily be constructed, or if the feature just mentioned is not needed, can be purchased " in the white " of a dealer, the size being right for stock bodies to be found in catalogs of several supply houses. An important point to be kept in mind is that all parts, though well protected from the elements, dust or mud, should be easily accessible.

The muffler M is of ample capacity to allow of a nearly noiseless exhaust, and also avoid back-pies-sure. The carburettor should be purchased, as very few mechanics have the tools, skill and experience necessary to make one that will give anything like satisfactory results ; generally the reverse. The best that can be purchased will be found the most economical in the end, and the increased efficiency of motor make the purchase desirable.

As the various parts are presented in the several chapters, detail drawings and directions will be given, with partial assembly drawings when needed. The wheels will be described in the following chapter, and those proposing to build the car can profitably look up, in the interim, the nearest supply house carrying hubs, knuckles, spokes, rims, etc. The diameter of axles is 3/4 in.