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18th November 1938
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Page 52, 18th November 1938 — CHASSIS DE N FOR '39
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THERE is evidence of hare and tortoise progress at this year's Commercial Motor Section of the Scottish Show, Whilst the big steps forward tend to overshadow the little ones, the developments that appear relatively small are far from being inconsiderable. At the same time, in comparing the major advances with the progress of the proverbial hare, we do not intend to suggest that they are likely to be transient.

A firm bid to establish producer-gas as a fuel for road vehicles has been made by the Sentinel Waggon Co. (1936),

Ltd. -When the standing of this concern is considered, together with the fact that it continued to build steam vehicles long after the other big steamer makers went over to oil, when the importance to the nation of a machine consuming home-produced fuel is borne in mind, and when the evidence available of the quality of the vehicles in general, and of the H.S.G. gas plant in particular, is examined, then a denial that the two Sentinel H.S.G. chassis On view constitute the outstanding exhibit in the Kelvin Hall cannot be lightly made, .•

We do not propose to make much further reference to them now, as considerable space was devoted to the subject in our issue of last week. Accordingly, we will wish them gaud fortune, and pass on to seek interest, considerable and not hard to find, elsewhere.

Deliberately we refrain from classifying in order of magnitude the other salient features of the Show, and our reason for referring next to the oil-engine developments revealed is that, as an alternative to petrol, oil, as a topic, appropriately follows .a mention of solid fuel.

Direct and indirect-injection combustion chambers stilt share popular favour_ It is significant, however, that the practice of the Associated Equipment Co., Ltd., appears to be to employ its new direct-injection unit for bus work, where economy is of great importance, stopping and starting are constant, and maximum speed is of • minor value, whilst it uses its latest Mark III Ricardo-type head for main-road goods chassis, of which speed is an essential characteristic. The relative governed rates of revolution of the engines of the two types are 1,750 r.p.m. and 2,000 r.p.m. respectively.

Oil Engine Still Makes Headway.

With regard to the spread of the use of the oil engine, the 1938 " Scottish " indicates that this is definitely marked, especially in the 30 m.p.h. class. A newcomer representative of this movement is the Thornycroft light six-cylindered model MDO, which, with bore and strokeof al ins, and 4* ins. respectively (3.9 litres), develops 75 b.h.p. It powers the Sturdy 5-tonner, itiCluded in the company's exhibit, which scales well under the 2i-ton limit.

Being a proprietary unit, the Perkins light " six (4.4 litres) might be expected on more than one make of vehicle. The number of concerns which is now offering it has, indeed, increased, and the headway this engine has made since its 'introduction in 19:37 is marked. Among • them are the Commer, Dodge, Dennis, Garner, Guy and Seddon companies.

Some of these names make news, and none can be allowed to pass without comment. Commer Cars, Ltd., was the first British concern to list an oiler in the small tn mediumweight classes. The Perkins was the unit then installed, and it is now the standard engine used when oil is specified. Its 4-5-tonner is one of the biggest-capacity oilers in the SO m.p.h. Class, also one of the cheapest.

On the eve of the Show the new oil-engined Dodge was announced. It is a 5-ton_ner, and is an attractive machine. For the purpose of the moment, its interest lies in the tact that it represents another chassis builder to take up the Perkins.

Dennis Bros., Ltd., long ago recognised the demand for oilers in the larger classes, and has employed Perkins units where customers. requiring smaller vehicles have asked for oil, It is significant, now, that although the company's new Falcon 32-seater passenger chassis, as shown in the Kelvin Hall, has the Dennis 75 b.h.p. four-cylinclered petrol engine, there is. a Falcon giving dernonstratiOns outside the Hall which is powered By the P6.

On the stind of Moodie and Co., a Garner agent, a 5-tonner of. this make is displayed, in which the Perkins engine is installed, and a feature is that, although well under the 21-ton limit, the wheelbase is 13 ft. 81 ins, and the platform 17 ft, long.

All the Guy machines shown have, in point of fact, petrol engines, but they are available also with Perkins oil engines. The Otter 6-tonner has a wheelbase of 14 ft. 9 ins.

A Promising New Lorry.

The Seddon, to he found outside the Hall on demonstration, is a new machine, and is notable for several points, besides its Perkins power unit. Rated as a 6-tonner, it has a 13-ft. 6-in, wheelbase and 16-ft. body, and its maker. Foster and Seddon, Ltd„ claims that these dimensions are the longest for the pay-load capacity of any oiler at the Show, Light weight consistent with strength, accessibility, simple maintenance and comfort for driver and mate are points to which the designer has paid attention. A full description here would be out of place we refer our readers to our issue dated October 28), but one point merits mention, as indicative of the practical manner in which this task has been approached.. The designer has remembered that front mudguards need to accommodate wheels which pivot on only a vertical diameter, He has, therefore, shaped them and their valances accordingly. He has made the centre or fop of the mudguard narrower than the forward and rearward parts. Hence, more space is afforded, just where it is wanted for the floor• of the cab. This structure—the cab— weighs, incidentally, under 24 cwt. There is yet another light oil engine to mention, the Gardner 4LK. It powers another. new 30 m.p.h. 6-tonner, the Foden. This is a highly interesting innovation, and knowing the reputation for sturdiness that vehicles of this make enjoy, and the long experience Fodens, Ltd., has had in the building of heavy and medium-weight vehicles, one may surely conclude, from the -arrival of this 6-tonner, that an orthodox machine weighing under 24 tons can carry 6 tons of pay-load--a ton more than twice its weight—with a margin of safety sufficient to satisfy even engineers of the exacting type begot by steam. This raising of the limit for pay-loads of 30 m.p.h. chassis is an important development indicated by the Scottish Show. Not long ago 5 tons was regarded as the very maximum for petrol-engined machines, and it was thought unlikely that a higher figure could be' possible. Now we have at least 'three 6-ton oilers—Foden, Guy and Seddon. .

Maximum speed, however, is not dn.The ability to carry 6-ton loads at 90 m.p.h.without infringing the Regulations is not the only ambition of operators. The 5-tonner may have the advantage of a bigger body allowance and a better power-to-weight ratio. In the petrolengined class, the .recently introduced Morris-Commercial forward-control model is a case in point, whilst another is the Bedford, a range of which make is seen on no fewer than four. stands.

The above characteristics are certainly the attractions of the new Thornycroft 3-tanner, as evidenced by its name —Nippy. Its advent points to a tendency to cater for the operator whose requirements are met by general handiness, rapid acceleration, and the ability easily to keep pace with modern traffic conditions, and who does not agree with limitations on body weight.

That 30 m.p.h. is not regarded as an essential to all moderate-capacity vehicles is evidenced by the popularity of the articulated type. In this connection, there is a number of exhibits to review The two popular mechanical-horse three-wheelersKarrier and Scammell—are well in evidence, and they have, this year, two four-wheeled counterparts. The Bantam, of the former make, and of 5-tons haulage capacity, is exhibited by T. M. trskine and Co. It has a 40 b.h.p. engine.

No longer, however, is it the sole representative of the small four-wheeled unit for use with a semi-trailer, for there is now, on the Dennis stand, this concern's new 75 b.h.p. 6-ton machine. The tractive unit displayed has been built for railway road transport, and, like the others mentioned

above, is equipped with quick-coupling. gear.

Thus, an increase in the number of this type available must be recorded, and the significance of this fact appreciated.

Reverting for a moment to the 3-ton class, there is a "come-back " to be noted. At the Show the new Chevrolet makes its first public appearance. Alone on the stand of Cameron and Campbell, Ltd., and exhibited as a chassis, it has evoked favourable comment from visitors on account of its good appearance and sturdy, straightforward design. Thus is the American challenge strengthened by yet another make.

Finally, in our consideration of the vehicles and the tendencies they denote, we must comment on the third new Thornycroft, aptly named the Dread. nought,, for the twin-steering six-wheeler is surely one of the most roadworthy types produced.

This arrangement of axles has come into favour comparatively recently, and, except for the fact that it necessitates rather a poor ratio of body length to wheelbase, has much to recommend it.

B18 . John I. Thornycroft and Co., Ltd., is not the company to take it up for the sake of following a vogue, therefore one may regard its policy in doing so as approving the type and the model as a sound proposition. It is noteworthy, also, that the power unit installed in the chassis displayed is the popular Gardner 5LW.

Outstanding brake developments include the use of the Bendix two-leading-shoe device by Fodens, Ltd., and the growing employment of wedge shoe-expanding gear, notably on the Leyland Badger.

An International D40 5-tonner is shown with a B.K.Booster vacuum device, operating through a Lockheed system, whilst we saw a. Renault with friction-servo motor driven by skew• or worm gear from the back of the gearbox. On the majority of vehicles above a moderate weight, Dewandre or F. and J. vacuum systems are in evidence. On the big Scammell rigid eight-wheeler, Westinghouse air brakes are employed. Little change is noticeable in the proportion of oilers on which vacuum is raised by engine suction as opposed to an exhauster.

Whilst, in some cases, brake systems on vehicles up to 12 tons gross weight have no power assistance, power servo gear is found on others of little more than hall that weight.

Our view is -that, theoretically, power is not, in -many cases, necessary, but that, in practice, especially when efficiency has diminished through wear or neglect, there is much to be said in its favour.

Although brake-shoe and operating :mechanisms have been much improved lately, also facings and drums, the use of servo gears does not appear to diminish.

Hydraulic systems evince no sign of waning popularity; a " hill holder " fe.atures On certain E.R.F. models; and an automatic adjuSter on. Daintier buses. Provision for controlling braking force in relation to weight transference, however, has made ,little progress.

In suspension systems, apparently, no demand exists for improvement where British roads are concerned. In this respect, it seems that the commercial-vehicle operator differs

from the private motorist, or else our manufacturers are slow to observe or to react. Alternatively, perhaps, tyre makers have done what is required to smooth out the bumps.

Only on the big Scammell „did we obsirve (in the class described) anything heterodox, and this concern's rubber suspension has been standardized now too long really to warrant that adjective. Yet it seems appropriate, because leaf springs are so deeply " dug in " and universally employed.

Outside -British-road usage matters are a little different, but even then leaf springs figure. They are supplemented, however, in the two cases in mind, namely, the Crossley Air Ministry machine and the Albion overseas tractive unit —on view coupled to a Brockhouse Kwieltfix semi-trailerby Gruss air springs. In the latter case these are employed at the back of the driving-wheel springs. Little has been-, seen of the Gruss device of late, and we suggest that it might be more often adopted.

Where, we ask, are torsion bars, independent suspension systems, and four-wheel drive? If they be unnecessary

luxuries, forwards

luxuries, cannot this criticism be more deservedly lodged at sacrifice of space and, still more, of accessibility and appearance?

We saw machines with grilles many inches ahead of the radiators they o'Ohe'ealed, and with mudguards, bumpers, -frontal decorations,. etc., arranged and mounted in such a Manner f.hat'.:. to 'gain access to the radiator for removal luxuries, forwards would represent several hours' work. Engines, too, we obseryeci, that looked as if mechanics with snakes for arms would be needed to work upon them. Against this, however, must be named the Dunlop rubber mudguards on the Leyland Titan—practical and of good appearance.

, Let un• not conclude on a critical note. Whilst there is scope for improvement in many directions, British commercial vehicles, as G. E. T. Eyston, in opening the Exhibition, remarked, are the best that are obtainable in the world and represent the best value. No visitor to the Kelvin Han can conic away from it bolding any other view.


Organisations: Crossley Air Ministry

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