THE CULT OF THE LIGHT SIX-WHEELER.
Page 47
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Details of a New Rigid-frame 20-30-cwt. Crossley, with torque Rods and Upswept Frame.
ANEW model rigid-frame six-wheeled chassis, which will he known as the. Crossley 20-30-cwt. light sixwheeler, has just been produced by Crossley Motors, Ltd., Gorton, Manchester.
This new chassis presents many features of considerable interest, and its construction is unusual in several ,respects. The pressed-steel-channel frame, for instance, is upswept in the neighbourhood of the driver's seat, and it is then carried horizontally to the rear end. It is also inswept to the dumb-irons. The rear axles are arranged on the semi-bogie principle with double, inverted, semi-elliptic springs at each side, these rocking on fulcruni brackets, the side members of the frame above these brackets being reinforced by a stout tubular cross-meinber carried in brackets bolted into the channels, the member also acting as an anchorage for the two universally jointed torque rods which form the means for remdving all torsional loading from the rear springs.
Both hand and foot brake are of the internal-expanding type operating on drums attached to the four rear wheels. All the shoes are faced with .Ferodo and are interchangeable, but easy adjustment without the need for tools is provided in both cases.
The power unit has four cylinders, cast en bloc, with a detachable head, lips on the head and cylinders being provided to facilitate separating the two when it is necessary to break the joint. The valves are entirely enclosed and are all on the near side. Aluminium pistons and forced lubrication enable the engine to be classed as a high-speed one. Its R.A.C. rating is. 15,6 h.p.; the bore being 3i ins. and the stroke 41 ins., giving a capacity of 2,388 c.c., or 145.78 cu. ins.
Three bearings are provided for the crankshaft, and the camshaft is driven by a silent chain provided With a means for adjustment. There is an nil-level gauge at the side of the engine, also high and low-level cocks are mounted on the sump.
Cooling is assisted by a fan driven by a .17-link belt, an adjustment being provided to take up wear. A single-plate clutch with asbestos-fabric friction faces takes the drive to a four-speed-and4everse gearbox mounted as a unit with the engine. Behind the main gearbox is an auxiliary one giving a further range of four speeds of much lower ratios to be used under exacting conditions of service. The actual gear ratios for the normal range are : first speed, 3.764 to 1; second speed, 2.60 to 4: third speed, 1.846 to 1; fourth speed, direct ; reverse, 3.764 to 1. Those for the extra low range are: first speed, 14.51 to 1; second speed, 10.03 to 1: third speed, 7.10 to 1; fourth speed, 3.86 to 1; reverse, 14.51 to 1.
Both the change-speed levers are mounted at the right, that for the auxiliary box being well below and slightly to the rear of the levers for the normal gears, so that there is no possibility of confusing them.
Between the gearbox and the back axle is an open propeller shaft with two universal joints of the star type, designed to permit large variations of axle position and forming self-contained oil reservoirs, and there is a second eardan shaft between the two axles of the bogieThe axle casings are each made from a one-piece steel stamping. They have roller bearing hubs and adjustable taper bear
ings for the worm and worm wheel.. The worms are above and give a ratio of 7.25 to 1. AU parts of both axles, with the exception of the worm shafts, are interchangeable. Strong steel loops carried by the frame limit the amount of axle drop at each end.
The total gear ratios between engine and road wheels are : normal range—first speed, 27.29 to 1; second speed, 18.85 to 1; third speed, 13.38 to 1; fourth speed, 7.25to 1; reverse, 27.29 to 1. For the extra low range they are : first speed, 105.28 to 1; second speed, 72.72 to 1; third speed, 51.49 to 1; fourth speed, 27.96 to 1; reverse, 105.28 to 1.
Steering is by worm and complete *heel provided with a means for adjustment, and the stub-axle pins are splayed to provide centre-point steering. . As the cooling water is circulated therfrio-siPhonically, the radiator provided is of unusually large capacity, with piping designed to permit unrestricted flow of the water. Oil only is used to lubricate the entire chassis.
Provision is made for mounting an electric starter, a 12-volt dynamo is chain-driven from the front of the engine, adjustment being provided for the chain.
A petrol tank with a capacity of 15 gallons is mounted on the dash, the feed being by gravity, a reserve supply being brought into use when necessary by a tap.
The main dimensions are: wheelbase to centre of bogie, 10 ft. 6 ins.; track, front, 4 ft. 9 ins., rear, 5 ft. 21 ins. ; frame length behind dash, 13 ft. 1 in.; bogie-axle centres, 3 ft. 31ins. ; standard tyre equipment, 32-in. by 4i-in. s.s. Dunlop pneumatics, singles on the front wheels and twins on the rear. The wheels themselves are of the detachable steel disc pattern.