Dodge Introduces New 26-seater Bus Chassis
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Extensive Improvements and Modifications in Design of Existing Models. All Models Fitted with New Lockheed Hydraulic Slotted-shoe Brakes
IN addition to the introduction of a new bus chassis, to take the place of its RBF 166-in.-wheelbase vehicle, Dodge Brothers, (Britain), Ltd., has incorporated extensive modifications and improvements in its existing range of models for 1438.
It is within the past six months that there has been a drawing and design section at the Kew works of the company, the result being thAt, apart from the MD21 25-cwt. and the MCX 30-cwt. vehicles, the whole range for 1938 embodies features of design evolved at Kew.
The new bus chassis, known• as the SBF model, is fitted with the T40 sixcylindered petrol engine, as used in all other models, with the exception of the 5-ton 'chassis.. This unit, which has side valves, has a bore of 85.72 mm. and a stroke of 103.18 mm., the piston displacement thus being 3,569 c.c. The compression ratio is 5.8 to 1 and the unit develops 73 b.h.p. at 3,000 r.p.in. with an R.A.C. rating-of 27.34 h.p. The torque is 150 lb.-ft. at 1,200 r.p.m.
The aluminium U-slotted alloy pistons are anodic coated, and each is fitted with four rings. Drop forgings, in manganese steel, are used for the connecting rods, the crankshaft also being a ,drop forging in carbon steel. A feature of this component, which weighs 73 lb., is the employment of seven counterweights forged integrally with the shaft. Forced-feed lubrication and downdraught carburation are adopted.
The engine, which is three-point mounted, is arranged to give an offset transmission line, the degree of offset at the rear axle being 9 ins. An improvement, common to all models. concerns the use of a rubber mounting block at the forward end, in place of the spring mounting previously employed.
A 10-in.-diameter single dry-plate clutch takes the drive to a four-speed gearbox with sliding pinion gears providing ratios of 5.85 (direct), 9.88. 18.37 and 37.4 to 1, with a reverse ratio of 45.9 to I.
An open Hotchkiss two-piece propeller shaft, supported in the centre by a ball bearing and provided with Hardy Spicer needle-roller universal joints, takes the drive to the underslung rear axle, which has spiral-bevel gears and fully floating axle shafts.
Inclined U-bolts.
In connection withthe suspension, which is by semi-elliptics, the spring; are so anchored to the axle as to give them the greatest freedom of action, this being accomplished by inclining the U-bolts, the narrowest span being beneath the spring. The rear springs, which are of the progressive type, are 52 ins, long and are composed of 12 leaves each 3 ins. wide.
As compared with the RBF model, a wider and lower frame is employed, and, further, it is deeply upswept at the rear.
The pressed-steel wheels, modified in design to give increased strength with
a saving in weight, are equipped with 7.50-in. by 20-in, low-pressure tyres.
This chassis, as are all others in the Dodge range, is provided with the newtype Lockheed hydraulic slotted-shoe brakes, which afford a servo action without the disadvantages sometimes associated with self-energizing brakes.
This feature is common to the complete range and, we are informed, the Dodge is the first British commercial vehicle to be so equipped. 011 the bus chassis the shoes operate in 14-in. drums on the front wheels and in 16-in. drams at the rear. The shoes are arranged for dual operation, a pedal controlling the hydraulic system and a lever applying the shoes by mechanical means. An adjustable steering column is provided in conjunction with an 18-in. wheel.
Regarding chassis lubrication, where the greasing points would otherwise be inaccessible, that is at the rear end, a system of grouped nipples has been provided.
The location of the petrol tank is on the off side of the chassis frame, the B63 total capacity, including a built-in three-gallon reserve tank, being 20 gallons.
In conjunction with dynamos of greater capacity than those fitted to the RBF model, two batteries, each of 57 amp.-hour capacity, are installed.
Some of the outstanding features of this new chassis, as compared with the one it replaces, are an increase in wheelbase to 177 ins.; wider wheel tracks, to give increased stability; radiator block and grille built as separate units; greater accessibility to the engine; improvements to the cab, giving greater comfort and visibility; better frontal appearance by using a deeper radiator shell, a longer bonnet and a lower scuttle, in conjunction with redesigned wings mounted integrally with the bumper.
A Wide Range of Models.
Excluding the bus chassis, there are 14 models available for 1938. in capacities ranging from 2.5 cwt. to 5 tons.
The two essentially American vehicles are the 25-cwt. (MD21) and the 30-cwt. (MDX), the former replacing a 30-cwt. chassis.
Of those which have been redesigned at Hew, the' 36-cwt., 2-ton and 3-ton chassis, all of which are equipped with the T40 engine and four-speed gearboxes, have been considerably modified. The frame is now deeper with stronger side members and, with improvements inthe method of anchoring the cross-members, a much more rigid structure has .bean obtained.
Front andaear springs are fitted' with single-leaf top rebound plates and have been designed to carry the increased maximum gross load without the nee'l for helper springs. Inclined U-bolts are used, as on the bus chassis.
Front and rear axles have been strengthened and the hub and wheel mountings modified to give greater security and better support for the wheels.
In the case of the 3-tonner, the track at the rear has been increased by 4 ins. In connection with the new Lockheed hydraulic braking system, thicker and wider facings are employed, the increase in braking area being 25 per -cent. Additionally, the brake master
• cylinder and combined fluid tank are now attached direct to the chassis side member, to the elimination of cross shafts and a separate fluid tank.
In order to provide a lower centre of gravity, the engine and gearbox have been mounted lower in the frame, whilst the forward engine mounting is rubber insulated as on the bus chassis.
The new features of the 4-ton and 5-ton models are identical with those of the 30-cwt., 2-ton and 3-ton models, with the exception of the following points:—
The frame side members have been designed to give a lower chassis weight, whilst the short-wheelbase vehicles are fitted with tipper hinge-brackets cast integrally with the spring brackets This model has also been modified to accommodate a tipping-gear attachment, an .additional cross-member 'having been introduced immediately_ behind the cab to carry the ram or lifting gear.
Increased Track.
On the 4-ton and 5-ton vehicles the track has been increased by 4 ins, at the front and by 5 ins, at the rear.
The power unit in the 5-ten chassis is the T42, a six-cylindered petrol engine, having a bore of 85.7 mm. and a stroke of 114.3 mm., with a piston displacement of 4,558 c.c. The maximum b.h.p. at 3,000 r.p.m. is 85, an -I the torque 175 lb.-ft. at 1,200 r.p.m. The compression ratio is 5.6 to 1. This chassis is the only one fitted with a five-speed box.
Altogether, a fine range which will undoubtedly enhance the Dodge reputation for providing vehicles of utility and reliability.