A POPULAR AMERICAN CHASSIS IMPROVED.
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How the 1926 Model 2-2i-ton Traffic has been Modified to Meet British Requirements.
(NE of the best known of the klAmerican chassis on the British market is the Trafbe. which is not only giving excellent service to many users, particularly in what might be called the heavy-haulage areas in the Midlands and the North, but certainly represents excellent value for money, the chassis price being 139.5 at Liverpool, where, in Norton Street, are situated the headquarters of the sole concessionnaires, North Western Motors, Ltd.
The chassis, although it has already proved a most serviceable model, will, in 1926, make still further appeal to users, as it now embodies a new Clark vertical banjo axle, the casing of which is formed in pressed-steel halves welded together, whIlst the final-drive gearing is by spiral bevels. This takes the place of the dualtype axle with internal-gear drive which has been employed until now. In cony nection with the new rear axle it is notable that the driving pinion is supported at both ends, or straddled, instead of being overhung, as is usually the case.
Its capacity is also greater, for that of the original model was 35-40 cwt., and, despite the increase, allowance is made for an overload up to a total pay load of 3 tons. To allow for this the chassis has been strengthened in almost every detail and exceptional attention has been paid to the brakes.
These work .s-ide by side in drums
51 ins, wide and 16 ins, in diameter. Each shoe is formed of a single band with one return spring. The levers are secured by serrations ; consequently, adjustment is simple and rapid. The bands are faced with friction fabric and carteasily be removed for this to be renewed. It will no doubt be' remembered that in the former model one set of brakes was of the external-contracting type, and the new internal brake forms a great improvement.
The frame is really exceptionally strong for a chassis of this size. The side members and some of the crossmembers are of rolled channel-steel, 6 ins. in depth, and at the rear a system of diagonal bracing is employed which assists greatly in stiffening the whole frame. In addition, the main crossmembers are well gusseted.
All the springs are of the semielliptic type, of ample length, and a• point in the springing is that short top
plates are employed above the main plates to strengthen them.
Single tyres are employed all round, these being of the Goodyear cushion type, 34 illS. by 4 ins, at the front and 34 ins. by 5 ins, at the rear.
A Continental engine, with a bore of 4/ ins. and a stroke of 41 ins., is bolted up as a unit with the three-speed gearbox, the whole being suspended at three points. This power unit is one of the most popular types on the market. It has a crankshaft, the journals of which are 21 ins. in diameter, and is supported in three bearings.
The lubricant is circulated by a geardriven pump and conveyed under pressure to all important bearings through the drilled crankshaft and via channels in -the connecting rods to the gudgeon pins..
Carburation is improved by the incorporation of a hot-spot between the inlet and exhaust manifolds.
All the main details of the engine are concentrated at one side, and at the near side are only the convenient oil filler and dip stick. The centrifugal water pump is mounted between the timing case and the magneto, the drive being taken through it to the magneto via a flexible disc coupling, whilst. in front of the crankcase, in line with these two components, is the fan pulley which drives the steel fan by means of a flat belt.
To prevent any danger of overheating, the radiator is slightly larger, having a header of greater capacity. This radiator is held down to the chassis by coil compression springs carried on bolts.
One particular feature of the old model has been 'retained, and that is the exceptionally small silencer. This is not only remarkably easy to clean but is quite effective.
The drive is taken through a new type clutch of the multiple-disc type, the friction surfaces being alternately steel and fabric. It has three internal springs. Behind the gearbox is a triple-disc flexible joint, then comes the centre bearing, suspended from a cross-member, and a shorter bar with two Spicer joints.
Ignition is effected by an American Bosch instrument and carburation by an American Zenith, The carburetter is supplied with hot air from an exhaust Muffle, the air being conveyed through a flexible tube. At the junction between this tube and the carburetter is an additional air valve which permits modifying the heat of the incoming air by admitting cold air. Carburation is improved by the incorporation of a hotspot between the inlet and exhaust manifolds.
The front axle is the usual_ Elliotttype I-beam drop forging with heavyduty Timken roller bearings for the wheels, which have 2-in, second-growth hickory spokes.
The steering gear is a worm and complete wheel, and the steering hand wheel itself is of 1.4 ins. diameter, The remaining controls consist of a centrally situated change-speed lever, spark and throttle levers an the steering column and the usual pedala, including ar. accelerator.
A cylindrical petrol tank of pressed steel and with a capacity of 10 gallon& is mounted upon the pressed-steel dash.
The main dimensions of this new chassis are: Wheelbase, 11 it 10 ins.; frame length from seat, 9 ft si ins.; turning radius, 28 ft.; road clearance, 12 ins., whilst the chassis weight is 1 ton 13 cwt. 2 qrs.
The equipment includes black enamelled front guards of 16-gauge steel and running boards of the same material, oil lamps, an explosion whistle and a full kit of tools. The chassis is completely painted in red and varnished.