TYPES OF TAXICAB CHASSIS.
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An Exacting Service, and the Vehicles which have been Evolved to Withstand It.
QIMPLE though it may appear .,to make o chassis suitable in every way ior taxicab work, there is no donbt that this most exacting form of service will take its toll of any, but the very best designs and constructions. Not, only is the daily mileage of a taxi often. very h4li indeed, but the nature of the work demands frequent gear changing and. considerable acceleration and retardation, so that the engine, transmission and brakes must be well up to the work. Reliability is obviously. of prime importance' lout, as any mechanical part is subject to failure at some time or other, he accessibility of the components should also be.. considered. Ease of con; trol „is likewise important as regards steering, braking and', changing. the gears. Then, of course', there are the Scotland Yard regulations to • consider, which are sufficiently v:ell-known to need no repetition here.
The bodywork is pretty well standardized nowadays. A large platform for luggage is invariably' provided beside this driver, further .space' being available on the fixed top: In the rear compartment there, will be permanent seats for two persons ..and, in -addition, a pair of folding seats.
As regards the chassis we cannot, perhaps, do better than give a brief resume' of the features of a few typical types. The Unic has steadily increased its reputation for re liability and consistent run
ning since its first appearance in nos, and it is new entirely
built in this country. The engine is of the normal fourcylinder type, with a bore and stroke hi 75 mm. and 120 ram. respectively, giving an R.A.C. rating of nearly 14 h.p. An interesting feature which has been found on the Tinie engine for many years is an automatic ignition kadvance; this improves the acceleration, and, by giving the correct degree of advance at all speeds, tends to greater efficiency: ' The transmission follows orthodox practice, consisting of a. leather cone The clutch; four-speed gearbox: and spiralbevel back axle. The suspension, following the practice consistently employed by this concern, embodies semielliptic springs at the front and threequarter elliptic at the rear. A provincial oab chassis has recently been evolved, and was shown at the Olympia Show for The first time last November. This is very "similar to the chassis used in London, but, in order to give slightly more power, the bore of the engine is increased from 75 inns, to 80 min. _Adequate brakes are provided on both models, controlled by pe.dal and hand lever: Although not of such long standing as the Unic, the Beardmore taxicab has attained4considerable .popularity both in London and the provinces. Rated at 15.6 h.p., the four-cylinder engine has a
bore and stroke. of 80 min. and 120 mm.,; both water and oil are circulated by pumps. The transmission consists of a Cone clutch, four-speed gearbox and bevel final drive. A pedal takes 'effect' on a transmission brake, while the hand lever is coupled to expanding shoes in the rear-wheels drums. As in the case of the Unic, semi-elliptic springs support the forward end of the chassis, whilst three-quiarter elliptics are provided between the frame a-nd the back axle. 1. A still more recent addition to the
classis which have been constructed to coniply with Scotland Yard regulations, is the 11.4 h.p.. Citroen. . Unit construction i.s adopted for the engine and gearbox, tbe four-cylinder power unit (68 mm. by 100 mm.) transmitting the drive through a single-disc' typo of clutch. From the three-speed. gearbox a tubular propeller, shaft communioates with chevron-toothed bevels in the back hXIe; the transmission brake is coupled to the pedal, the hand lever operating the rear _ wheel brakes through the medium of a compensator.
In this chassis an acciimnlatar, -dynamo and starter Motor are standardized, together with an electric horn, two electric headlamps and a tail lamp. In addition, two oil lamps are supplied. In this respect the Citroen differs from' other makes in which oil lamps are standardized,. with electrical equipment, optional at an increased cost. Of course, the lighting equipment necessary depends largely upon the dis trict .Whieh the cab it to .operate, those used in city areas really requiring nothing More than oil lamps.When freqUent runs into the country have.. to be.. made, however, electric lighting is certainly very desirable, and even outlying suburbs may be very badly lit, and often contain a number of unmade roads, in which the unwary taxi driver may easily become ditched or mired.
Lastly, mention mist be made of the Yellew cab,
• which is very Widely, uSed in America and is being intro.dueed into this country. The chassis is constructed on thoroughly seund lines; and should be' quite snecessful; it complies with Scotland Yard 'regulations. . A feature of the bodywork is the wire-meshreinforeerhent. JO the glass panels separating the driver and passengers. Electrical
equipment is standardized. •
Many other makes of taxicab are in use: at the present time, but most of these are not at present being marketed.