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21st October 1924
Page 15
Page 15, 21st October 1924 — ANOTHER SIX-WHEELER FROM THE STATES.
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Which of the following most accurately describes the problem?

The Latest Multi-wheel Vehicle Embodying Original Features of Resign.

A LTHOUGH we are aware of certain rtinteresting and exhaustive experiments which are at present being undertaken in this country with a view to the ultimate production of a rigid sixwheeler, we have yet to witness the appearance of the first British conception of a vehicle of this description. • In this sphere of manufacturing enterprise American manufacturers have certainly taken the lead and gained much useful and practical knowledge of the potentialities of vehicles with more than four wheels. Whilst many multi-wheeler developm.ents have been reaerded in the United States some British makers, have been giving support to the efforts to increase load-carrying capacity. by the use of semi-trailing units with their chassis.

The fields of employment for the rigid six-wheeler and the tractor-trailer (with an equal number of wheels) respectively., probably possess dissimilar characteristics; and, whilst the latter is used chiefly to enable greater tonnage-to be carried, the object of the designers of the former is to dispose practically within the compass of the conventional four. wheeler additional wheels so that the weight carried per wheel is reduced and the area of contact with the road 5iirface appreciably increased. In a sense, therefore, the development of each type is, for the moment, proceeding along divergent channels.

It is conceivable, however, that the design of the multi-wheel vehicle may eventually result in heavier and longer loads being carried, but such developments must obviously be confined within definite limits if the outstanding advantages gained by increasing the number of wheels are not to be negatived. Sufficient research work and investigations have been carried out in the United States to warrant the assertion that the rigid six-wheeler has passed the experimental stage in that country; and that these developments are proceeding apace and being watched with keen interest in all parts of the world is indicated by the fact that American vehicles of this type are now being exported for passenger service. Only a few weeks ago such a machine was shipped for service in Switzerland.

However, our campaign in support of the merits of the multi-wheeler is likely to bear fruit at an early date, for it may not be more than a few weeks before the first rigid six-wheeler makes its debut. If for no other reasons than that it indicates a practical recognition of advanced principles of design and a desire to maintain the prestige o,f the commercialvehicle industry of this country, its appearance will, we feel sure, be wholeheartedly welcomed, In the meantime we cannot afford to ignore the appearance of another new six-wheeled chassis in America, since it represents the combined efforts of two men well known in the industry—Mr. C. M. Crosson (a large user of motor vehicles) and Mr. Arthur H. Lacey (a prominent Ongineer)—who have concentrated on perfecting details of its design over a period of two years. The new C-L chassis—it takes its title from the surname initials of its designers—is to figure on the manufacturing programme

of the Peerless Stages Incorporated, who are constructing a new works at Oakland, California, for the purpose. The C-L chassis embodies several new features in its design, particularly With respect to the form of drive employed and the system of suspension, and these

have been protected by patent. The four wheels forming the rear unit are all driven and the braking mechanismacts on each of them. The weight on this portion of the assembly is equally distributed between the four wheels, each of which is free to adapt itself to irregularities in the road surface without any tendency to distort the prings. The functioning of the springs, moreover, does not affect the position of the wheel centres relative to one another, and this factor is said to ensure a 'marked degree of stability.

The two rear wheels on each side are connected to the ends of ..a " walking beam," and, since, the driving shaft to each wheel has universal joints there are no other rigid connections. The "walking beam" can, in turn, rotate about the central point which is attached to the semi-elliptic spring assembly, the ends of which are connected to the frame. This arrangement reduces the unsprung weight to the minimum. There are three differentials embodied in the assembly of the rear unit.

The form of drive employed is of the spiral-bevel-gear type and consists of three sub-assemblies, two of which are identical in construction. • These are the bevel-gear units, and the third houses the helical gears carrying the drive to them. The driving unit is supported directly on the main frame and does not represent unsprung weight. The drive to the wheels ig transmitted by way of flexible shafts, which revolve approximately at the speed of the engine. The final reduction is by internal gears in the wheels, and this form of construction enables a considerable saving of weight and bulk to be effected in the driving parts and permits the employment of oversize parts -when replacements have to be made.

We have elected to deal with the salient features of the new C-L sixwheeler without reference to its main components. We have followed this course because, in many respects the designers have chosen to place reliance on units built by makers who specialize. For instance, the engine is a WellmanSeaver-Morgan four-cylinder unit with a bore and stroke of 41, ins. and 6 ins.' respectively, and it conveys the power through a Brown-Lipe clutch to a gearbox of the same make in which four or seven speeds can be supplied at option. The front axle is a Timken, and all the wheels are Whitcomb aluminium discs fitted with pneumatic tyres either of 32-in. by 6-in. or 36-in. by B-in, size, according to the requirements of the purs chaser. The chief dimensions of the chassis are : Wheelbase (to centre of rear portion), 18 ft. 2 ins. ; track (front), 5 ft. 8 ins (rear) 5 ft. 10 ins., and the vehicle i can turn n a circle 5 ft. 10 ins, in diameter.

An example of the C-L chassis was subjected to some rigorous tests two or three months ago, when sacks of ballast and Siebel air-spring seats were used to represent the load. In all about 1,500 miles were covered on this experimental run, arid from information in possession of our contemporary, Bus Transportation, to whom we owe our expression of thanks for the details of the machine, it would appear that the behaviour of the chassis was all that could be desired.


Locations: Oakland

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