COMMERCIAL VEHICLE PROGRESS IN AMERICA.
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An Analysis of the Trend of Design. Pr ices and Production.
AINIERICAN COMPETITION is the only competition with which manufacturers in this country have to
i reckon, and on this account, it s always of interest clearly to watch the trend of design in motor vehicles manufactured in the United States. America has earned a name for big figures, and all forms of production not only motor vehicles, are reduced to a statistical level. Figures collated in a useful manner often provide illuminating and convincing evidence, which it is difficult readily to grasp in any other way, and it is a matter for regret that British Manufacturers are very reticent to divulge information similar to that issued by American manufacturers.
We have just perused an analysis of production, prices2 and trend of design applying to American vehicles manufactured during 1921, which is published by our New York contemporary, The Commercial Vehicle. We reproduee on this page a composite diagram showing at a glance the variations in the final drives of commercial vehicles during the past „lour 'years. So far as prices are concerned, considered by models, there has been a general reduction trend all along the line, and perhaps the best way to present a comparison of figures. for 1921 and 1922 is in the following manner—the first column showing the capacity of vehicle, the second the average price in dollars in 1921, and the third the 1922 price :—
It will be noticed that, with the exception of the 15 cwt. and 24 ton models (both of which have increased slightly), the general tendency is for prices to fall, and the view of many prominent men in the industry is that prices are still too high, and that trade will not show a. healthy revival until further reduetions are made. The average price of all models during 1921 was 2,881 dollars, as compared with 2,797 dollars for 1922. The difference between the figures " merely represents a decrease of 2.9 per cent., although individual reductions varying between 5 and 50 per cent, have been made by certain manufacturers. So far as production is concerned, American makers have not escaped the general trade slump, as is indicated by the fact that, whereas in 1920 348,000 commercial vehicles were produced, only about 200,000 were manufactured in. 1921—a falling off amounting to 42.5 per cent. The decrease in production takes the industry back to where it was in 1917, when 190,000 industrial vehicles were produced, although it should not be forgotten that the 1921 figure merely represents a temporary set-back to a curve which had steadily and unceasingly ascended from 1910, when only 9,500 were made.
The diagrams at the bottom of this page, which show changes in the various forms of final drive, should be carefully studied. It will be seen. that for the past three ;pars worm drive has increased in iavour from 65 per cent. in 1920 to 714 per cent in 1922, the intermediate year registering a percentage of 613k. Double-reduction gearing and bevel gearing have shown an increase, the tormer having progressed 100 per cent. (from 2* to 44 per cent.) as between 1921 and 1922. Internal gear drive, which is a typical
pical form of American drive after having risen 7 per cent. in 1920 to 26 per cent. has shown a marked tendency to lose cent., and has now decreased to 14i per cent. for 1922, as against 211 per cent. for 1921. Chain drive has remained comparatively steady for the past three years, although the tendency is for it to decline slightly. All these final drives averages are calculated on the number of models offered in each particular year, and not on the total number of chassis produced.
Rear-axle design continues along definite lines, the numerous new axles produced in 1921 being chiefly designed for high-speed lorries and buses. The-number of models of each of the various types fitted to commercial vehicles in 1921 and 1922 respectively was as follows :—Bevel 19 and 24, chain 24 and 15, double
reduction 7 and 15, internal gear 114 and 48, worm 361 and 238, external gear 2 and 0, the total number in each year, including 4 not listed in 1922, being 527 in 1921 and 344 in 1922.
Commercial vehicle wheel design during the past year was influenoed by the demand for lighter construction and great resiliency and strength. So far as wood wheels are concerned, there has been a tendency to dispense with the wooden felloe and to replace it by a steel rim, which results, in the case of a large wheel, in a saving of weight to the extent of 25 to 30 per cent. Many new cushion wheels have been introduced, whilst the pressed-steel disc wheel has been adopted for high-speed vehicles. There are now 203 models of the wood type of wheel supplied, as against 334 in 1921, and 126.3models of the metal wheel, as against 190 last year The percentage of models supplied is as follows : —1921 wood 63.4, metal 36.1; 1922 wood 59.0, metal 36.6.
So far as clutches for industrial vehicles are concerned, American manufacturers appear to favourftheidry-dise type, eitherrof the single-disc or multipledisc pattern. As a matter of fact, more than 80 per cent. of the 1922 commercial models are fitted with clutches of the dry-disc type, which represents an increase of 10 per cent, over the 1921 figures, the actual numbers for the two years being 285 :nut of a total'of 344 in 1922 and 379 out of a total .of 527 in 1921. The next type of clutch in favour is the dry-plate type.
Engine design during 1921 has been towards simplification of design in order to render parts readily replaceable and easy to repair. The well-known Wisconsin company have, for example, introduced a model with removablei cylinder barrels, whilst others have included removable cylinder beads and provided facilities for the ready removal of valves. Much progress has been made towards the elimination of engine vibration by the use of larger diameter crankshafts and deeper crankcases. One maker is fitting a counterbalanced crankshaft, whilst another has provided adjustments for end-play in the camshaft and crankshaft.