A NEW SINGER
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Low-loading
Passenger Chassis
Full Particulars of a 20-seater Chassis Which Follows Somewhat on the Lines of the Goodstype Vehicle Already Described in Full in the Pages of " C.M."
IN the issue of The Commercial Motor dated September 3rd the centre pages were devoted to an exclusive description of a new product of Singer and Co., Ltd., Canterbury Street, Coventry—a 2-ton chassis built on thoroughly modern lines and incorporating all the good features of the best modern automobiles practice. In that article we gave brief particulars of • ri.motorbus and coach chassis, suitable torn 20-seaterbody, which was then on the stocks. This vehicle has now come, into being and, like the freight chassis, has been Snbjeetecl .te searching tests. Again. we are able -to'give7.the'firat, fully illustrated description of • the new vehicle,: fer..thie :benefit of our readers who are sinterested in the, Operation of relatively sinall buses' and motor
coaches.
In such items as wheelbase, frame, disposition, general build and so on, the passenger vehicle, of course, bears little or no resemblance to ths goods chassis, but the engine, for example, is identical, likewise the clutch and gearbox, whilst the rear .axle,. although of the. inverted-worm type, is almost a facsimile of that in the freight chassis, but with the casing turned upside down.
• `• ' Standardized Parts .KeepDawn Production Costs.
Naturally, this co-ordination of models has enabled the Singer .-corominy to •keep'produetion costs down, which, in turn ;• means :that the vehicles arc thoroughly competitive in • price and, taking equipment'' into consideration, represent excellent value-for-money propositions.
Before going into details it would seem an, opportune moment for giving a few particulars of the main dimensions of the chassis, as all operators are particularly interested in the amount of space available for seating accommodation, etc. With wheelbase and track dimensions of 13 ft. and 4 ft. 11 ins, respectively, the vehicle can be turned around in a circle 54 ft. in diameter. The overall length is no greater than 20 ft. 4 ins., despite the fact that a body space, i.e., from the dash to the end of the frame, of 16 ft. 2 ins. is available and this with only a moderate overhang behind the rear axle. Other interesting dimensions concern the height of the chassis ; the top of the main channels of the frame is 1 ft. 11i ins, above the ground, thus, after allowing• for the body. bearers., floorboards, etc., bringing the floor level to 2 ft. 3 ins. The chassis weight is 354 cwt. Having given it general outline of the vehicle, we can now turn to a consideration of details, but as the power
unit, etc., are similar to that of the goods chassis we must refer our readers, to our issue ,dated September 3rd.
The engine, clutch and gearbox are formed as a unit, which is mounted in a sub-frame, the two components— the unit and the sub-frame—being insulated from one another_ by means of • rubber -buffers. The design of the engine follows modern practice; thus the four cylinders (each having a bore. of 95 ram. and a piston stroke of 120 mm., giving a total cylindercapacity of 3,053 c.c.) are formed in a monobloc casting with the crankcase top.
Overhead valves are contained in a detachable cylinder head in which the combustion chambers are formed and, as they are machined all over, uniformity of compression ratios for all the cylinders is assured. A robust crankshaft is carried in five main bearings of exceptional length, all of which, together with the big-end bearings of the connecting rods, are fed with oil from a full-pressure system, in which proper and efficient oil filters are installed.
There are many features of the engine which call for comment. The reciprocating parts, for instance, are light in weight, consequently relatively high revolution speeds can be attained under load without excessive vibration becoming apparent, from which it follows that the power output is extraordinarily good. Actually, nearly 60 b.h.p. is developed at maximum revolutions, but, at 2,000 r.p.m.
and 1,000 45 b..h.p: and 23 b.h.p. respectively are available, which goes to ,show that,, $t4 high torque figure is obtained throughout the whole range. -Another point worth mentioning is that the bearing surfaces of the tappets, cam faces, etc., are generous. and this, in connection with an arrangement whereby tim inertia of the valve parts is kept low (consequently light• springs can be used) means that the unit should run for, prolonged periods without requiring the replacement' of any parts.
In order to provide for easy gear-changing, the clutch free-member--of the single-plate variety—is exceptionally light, as the friction rings are attached to the flywheel and back plates respectively. We can testify to the smoothness of operation, for we tried a similar type of clutch on the goods chassis and were fully satisfied on all points.
Further, we are assured by the maker that the special steel employed for the manufacture of the free-member enables the clutch tube slipped almost indefinitely without the co-efficient of friction being materially affected. Righthand change is provided for the four-speed gearbox, the standard ratios of which are: first 34.8 to 3, second 17.9 to 1, third 10.5 to 1 and top 6.5 to 1. There is, however, a specially low axle ratio of 7.25 to 1 available for the benefit of those users whose vehicles opera :e hi hilly country.
A Peculiar Transmission Layout.
The design of the transmission is something of an innovation, for the forward end of the torque tube is hinged on the' gearbox, with a further joint at the junction of the torque tube proper with the gearbox hingedsobracket, to take care of the cries-cross movement of the rear axle, it may here be mentioned that all the swivels are fitted with rubber bushes, which are so designed that the distortion of the rubber itself suffices for all ordinary movement of the axle. The torque tube appears to be sturdy, for strengthening stays run outward from a point roughly
mid-way along the tube. to the rear axle casing, in such a Manner that structural triangulation is' obtained in both the vertical and horizontal planes:
As with the goods chaSsis,lonr-wheel brakes are employed and are operated by the • pedal through the medium of a vacuum-servo motor; central adjustment for all the brakes is provided in a convenient position, whilst individual adjuatthent Can be effected by taking up sleekness in any of the pull rods.
No description of, a modern vehicle would be complete without making reference to thc. equipment. Included in
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the' chassis specification are the front wing's alit" stephoards, the instrument board'With •a speedometer, the lighting Mid starting switches, an oil-pressure gauge; petrol
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gauge, ammeter; ignitibit switch and dashlamp; a 12-volt lighting and starting set complete with all lamps, together with an electric horn operated from the steering column. A spare wheel shod with 7-in, by 20-in, pneumatic tyres is also included. Lubrication of the chassis details is ,provided for by a 'AMAX central foot-operated oiling system.