OUR BUSINE AN'S GUIDE.
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Striking features of the Scammell fuel-oil tanker are the radial air compressor driven from the front end of the crankshaft and the combined tank and frame of the trailer portion.
An unusual arrangement of the engine is adopted in the Yorkshire steam wagon. It is a two-cylinder vertical type disposed in the centre of the cab.
In the new. F.W.D. accessibility has been greatly improved by slotting the cross-member supporting the rear of the gearbox, permitting this unit to be lifted out in a quarter of the time formerly necessary.
I good example of the powerful brakes now fitted to steam wagons can be seen on the rear axle shown on the Atkinson stand.
The cut-away working model of the Beardmore 15-20 hp. engine gives an excellent idea of the construction.
A neat fitting on the overtype Tilling-Stevens is the hub-cap step.
On the Tilling-Stevens the laminated spring drive to the dynamo has been replaced by two fabric joints, and the lighting dynamo is driven from the front end of the driving motor.
The worm on the Daimler chassis can actually be seen, although not turning, as it is mounted in a glass housing.
One of the smartest goods vehicles is the Leyland glass-lined milk tanker for United Dairies.
The wonderful flexibility of the Kegresse track is dearly shown by a Citron especially staged on a good imitation of rocky ground.
A feature of the Foden steam wagon is the huge brake drums on the rear wheels. In the Orwell electric the steering layout is most unusual. There Is a bell-crank lever fulcrumed in the centre of the front axle, with separate rods leading to the steering arms.
The Dennis servo-brake mechanigin on the new passenger chassis deserves particular attention, as also does the change-speed layout.
One of the longest torque tubes is that on the 30-cwt. Dennis.
In the Daimler C.M.-type bus the front cylinder is cut away to show the sleeves.
• The double cantilever rear springs on the polished Unic chassis deserve notice. Excellent protection is afforded the driver on the Sentinel built for .1. Lyons and Co., Ltd., a V-fronted screen being provided. The Garrett wagon is also equipped in this manner.
An unusual feature of design is the jointed propeller shaft on one of the Lancia chassis, this consisting of several sections bolted together.
One of the best working models in the Exhibition is the Chrysler part-sectioned chassis.
Splashguards are fitted to at least one vehicle, this being the Dodson covered double-decker. The guards are those invented by Mr. H. C. Hyde, of Lincoln. An unusual type of body with many possibilities is the 30-seater fiexible fabric type built by the Union Motor Car Co., Ltd., on a Karrier chassis. Although a 30-seater, it weighs under 19 cwt., a saving of more than half a ton over many of ordinary construction. SilenCe is one of its chief attributes.
A new arrival in the batterY electric market ,is the G.V. tractor, which is a neat and powerful. machine designed to haul from two to four tons.
In the opinion of some the double-reduction axle is likely to prove a serious competitor of the worm type. The .most modern of these axles is the Leyland with spiral bevels and double helical gears, a combination which should prove absolutely silent.
Those who are inclined to believe that the design of an efficient steam engine is an easy matter would do well carefully to examine the model of the AtkinsonTJniflow and to study the action of the relief valves in its pistons.
• Very unusual features are to be found in the Reo chassis, these including an engine with overhead inlet and side exhaust valves and a starter connected through the medium of a roller chain.
It is being recognized that the life of a body depends greatly upon the strength and freedom from twist of the chassis frame. These are now being braced in a much stouter manner than formerly ; for instance, both in the Maudslay. and Leyland use is being made of strong tubular cross-members, and where channel types are employed these are being well strutted.
What is, we believe, the only vehicle in the Show in which a radial engine, is fitted is the Scanamell Autovan. On the Saurer 43-tormer, the radiator protecting bar hinges down to form a pushbar for shunting trailers. '
In places where ordinary bushes are apt to be neglected and where the rubbing speeds are not great, Ferodo anti-friction material is now being employed on some chassis, including the Leyland.
With the increased efficiency of the cooling systems on many engines and the development of standard types suitable for use in all parts of the world, it is proving essential in some instances to control the cooling effect, and thermostats are being employed for this Pllaoset
The design of the F.W.D. has been much improved and cleaned up by the omission of the triangulated torque rods and the cross-spring at the rear, semielliptics only now being employed for the back end.
One of the best examples of accessibility in steamwagon design is afforded by the Mann shaft-driven Express model, in which the engine is carried across the chassis under the frame ,so that the cylinders are accessible at one side and the crankcase at the other.
It is of little use designing a low-frame chassis if the body be not also kept low on the frame. Notable designs in which this point is kept in view are the Hall Lewis, Garner, Karrier and Albion.
Most up-to-date features are to be found in the new Railless low-floored car. These include a double-reduction axle with internal gear drive, four-wheel brakes and aluminium-alloy road wheels.
A most unusual example of design is to be found in the Sentinel engine, in which the crankshaft is equipped with pinions so arranged that it combines its own work with that of a differential gear; One of the neatest spring devices for a towing hook is to'bekfound on the Thornycroft Hathi. It is also used on certain of theirtother vehicles. The towing hook is carried in the centre of a laminated spring, the ends of which are secured to the tractor or vehicle.
Amongst the tractors which are exhibited are the Thornycroft Flathi, with four-wheel drive; the Latil, also drivenlon all wheels; a G.V. electric type; and the well-known Austin.
In the Burford dual-type axle, the transmission brake shoes are anchored to the vertical banjo-type dead axle, and act on a drum in front of this.
In the new Halley engine the camshaft is carried in an oil-bath 'immediately behind the tappet cover, and is thus instantly accessible. With the increased length of wheelbase utilized on many of the new models, together with the higher speeds at which they are run:, it has been found essen
tial to, divide the propeller shaft, thus avoiding undue•whip. Usually a two-piece shaft with a Skefko self
aligning bearing at the centre is enaployed, as in the Albion and numerous others ; in others, including the Garner, a three-piece shaft is utilized. In the lastnamed there is the additiobal feature that the centre portion is permitted to slide and is mounted on Timken taper roller , bearings.
A neat and practicable method of mounting the headlamps on the new A.E.C. chassis, each having a ball carried ih a, bracket having a spherical seat which is bolted to the radiator side bracket, not L only permits Individual adjustment of the lamps, but also allows either lamp to be turned right round to facilitate work on the engine or elsewhere at night.
Woodhead springs are winning an excellent reputation. In their latest form the top leaf is divided, the inner ends being formed into eyes which can be,secured to brackets on the axle in such a manner as to prevent any risk of the axle shifting through stresses caused by driving or braking. These springs can be found on the new Garner.
Overhead-valve engines have not yet come into general favour, but it is significant that the makers of the Leyland have adopted rocker-operated overhead valves on the engines of their new passenger vehicles. These are also used on the Berliet, and we must not forget that pioneer, the Maudslay, wit,Ji its overhead camshaft. On the M. and D. the valves are also arranged and driven in this manner.
Front-wheel brakes are certainly coming into general ,favour and are being fitted (either as standard or at the option of the purchaser) to the majority of passenger vehicles, and in not a few cases to those for goods carrying. So far as British Vehicles are concerned, these brakes are mainly of two types—the improved Perrot type supplied by the. Kirkstall Forge, Ltd., and the Rubury-Alford and Alder type marketed by Clayton Wagons, Ltd.
In the latest Halley passenger models the transmission brake has been movedo from the tail end of the worm shaft to a drum situated amidships and carried by a section of propeller shaft supported on Timken bearings, the drum and shaft forming a unit carried by two cross-members.
One of the neatest safety-door arrangements is that employed on the Guy, in which the rear door can be operated from the driver's seat as well as from inside and outside the bus. Servo operation of the brakes is receiving more attention, but is by no means yet general. There are two main types—that in which a separate servo device is employed and that in which one brake forms a servo mechanism for applying the other. Of the former, the most notable is the Dennis; as a matter of fact, this is really a combination of the two, as the servo action assists the application of the rear brakes and actually applies those at the front. Then there is the Renault, With a. friction clutch operating in either direction.
In the second category of front-wheel-brake types there are the Maudslay and the Leyland, in both of which the rocking of the anchorage for the transmission brake shoes applies the front brakes. We must not forget that, in a sense, the Westinghouse method of brake operation is a servo device, for it develops far more power than could be exerted by the driver unassisted. The Westinghouse is being employed on several chassis, including the new Karrier six-wheeled bus. Another servo device is the Clayton, as used on the new Vulcan.
Low-frame-level chassis take pride of place in the Show. In-the majority the frame is upswept over the rear axle, but notable exceptions to these are the undersweep in certain Karrier models and the straight frames used in the Latil chassis—rendered possible by using front-wheel drive in one instance and securing the differential to the frame and driving the rear wheels through cardan shafts in the others.
Methods of insulating the bodies of passenger vehicles from road and chassis vibrations are exemplified by the large Bristol bus, in which the body is carried by rubber cushions, and there is no metallic connection at all, and on certain vehicles equipped with the Strachan and Brown method of body suspension by semi-elliptic springs.
A notable advance has been made in the use of single-plate clutches. In some of these the friction material is attached to the plate, whilst in others it is carried on the flywheel and a pressure plate. Such clutches have long been used on the Bristol and Halley chassis and are now being employed on the Albion, 1-ton Guy, Leyland, Chrysler, the W. and G., the Gotfredson, M. and D., and others.
Accessibility is a matter which has received a considerable amount of attention from designers. In many chassis it is quite possible to remove any one of the units without disturbing the others, in some cases even without disturbing the body. For this reason gearboxes are being suspended from cross-members instead of being mounted upon them, and the connecting shafts can usually be disconnected and swung aside to permit the unit to drop. A good example of gearbox accessibility is afforded by the new Leyland, in which the cover occupies the whole of the near side.
Advances are being made with the six-cylinder engine, units of this type being employed on the big Karrier, the new W. and G., Vulcan, Reo, Fiat, Guy, and Thornycroft's Hathi tractor. We Must not forget the pioneer Halley engine.
Better efficiency in power Units is being obtained by the employment of light reciProcating -parts, and good examples are the Bristol, Star and "M. and D. Chassis, which have Duralumin connecting rods and aluminium
alloy pistons. r • The maximum road speeds of _ some of .the . latest passenger models are . of tilde can reach over 40 'M.p.h., and;everi 50 M.p.h. Is claimed in some cases, but users need not be alarmed, because this does not mean that the vehicles will be run at this speed but merely that the engines give rapid acceleration and high efficiency—tremendous advantages in traffic:driving and 1111-climbing. An unusual feature of the new Bristol is that both the dynamo and the magneto are mounted vertically, giving the maximum of accessibility. This method of mounting the dynamo has also been adopted for the new 2-ton McCurd.
It is interesting to find that the transmission brake, which for a time appeared to be going out of fashion, is once again much in evidence, even on most of the new models, this being probably' due to the increasing reliability of cardan shafts and joints.
The only two rigid six-wheelers in the Show are the new Karrier bus, which is exceptional in that it includes an offset drive and a spectacle frame, and the Longframe, which is shown in several types, the basis being Chevrolet chassis, one carrying a bus body built by London Lorries, Ltd., and the other a lorry body by Spurling Motor Bodies, Ltd.
Accessibility in overtype models is not always so good as might be wished. This cannot be said, however, for the Garner, in which the cab sides hinge forward, exposing the engine. In the 2-ton Bristol, also, a fitter can stand between the cab sides and the engine to make any necessary adjustments.
Adequate and simplified lubrication is receiving increasing attention. Grease-gun and oil-gun lubricators are fitted in the majority of cases, whilst there are several outstanding examples, such as the Guy and the Garner, in which oil reservoirs are provided foD important details.
Examples of chassis embodying front-wheel drive are the Lath, the new Scammell Autovan and the S.L.M. built by the Swiss Locomotive and Machine Works. Incidentally, the last-named is, we believe, the only vehicle in the Show equipped with a front lifeguard, the practicable tramcar type being permitted by the long overhang at the front.
Simplified gear control will be found on the A.E.C., and a special type in which the casing of the gate also forms the selector box is used on the Karrier sixwheeler, but the Bristol still remains unchallenged with its one-rod control.
A mechanical joint which is being used to an increasing extent by some of our best-known manufacturers is the Spicer. This presents the advantages of practically perfect balance, combined with a long life, partly due to its total enclosure and constant lubrication.
It is becoming almost standard praCtice to fit a joint of the fabric type between engine and gearbox, as this assists in damping engine tremors.
Trussed frames are again corniag to the fore. Good examples are to be found in the Halley range of models.
Some good ,examples of wagon and cab coachwork by :T. Walters and Co., of Rugby,. will ,betfonnd on Stands 111 and 2. A Walters' three-'c ay-.strew tinning gear will also be found in use It is a simple and efficient type, of robust constrnetion.