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Fast and Economical The Tharru 5tonL orry By L. J. COTTON,

14th October 1949
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Page 38, 14th October 1949 — Fast and Economical The Tharru 5tonL orry By L. J. COTTON,
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ALTHOUGH t h e lastest version , of the Fordson Thames chassis was shown in prototype form at Earls Court last year, it was only recently that full production was started on this model, and with the co-operation of the manufacturer, "The Commercial Motor" was offered one of the first models off the "line" for testing.

The test machine had not completed its first 500 miles when the trials were started, but the results of the fuel-consumption tests and the good turn of speed of over 50 m.p.h. with the standard ratio axle, showed it to be an economical machine to operate for all types of haulage. An optional high-ratio axle is available which should give improved consumption figures for long-distance hauls, whilst yet another ratio of 7.6 to 1 is offered for operators whose vehicles have to negotiate gradients in the order of I in 4.

Operators of Fordson Thames vehicles have found little to criticize in their performance or maintenance, therefore the manufacturer has made no radical change in the design of the chassis. The eight-cylindered petrol engine, With minor modifications to the mountings, and the distributor automatic advance-retard mechanism, is retained, in conjunction with the four-speed gearbox and enclosed propeller shaft.

Major alterations have been made in the braking system, and it now embodies a vacuum-servo acting through a Gicling hydraulic system, to two-leading-shoe ..units at all wheels. The vacuum tank, hciused outside the frame behind the cab, is exhausted from the engine induction manifold. The frame assembly, steering, axles and wheelbase remain practically unchanged, but a .14gallon petrol tank is now fitted.

A great improvement has been made, without sacrificing load space, by designing. the cab for semi-forward control. Of all-metal, welded construction, the cab, wings, bonnet, fairings and other component parts are formed from units, which may be replaced from stock.

The new cab has many advantages over the former assembly. From the angle of

maintenance, t h e engine is more access144

ible, and this unit, complete with gearbox, may be removed from the chassis in approximately an hour. The fuse box and other electrical. details are mounted under the bonnet on the scuttle, and the battery is carried in an enclosed case between the two seats. With a relatively small portion of the engine and bonnet projecting into the cab, the driver benefits by a moderate cab temperature in hot weather.

Built-in head lamps and the flowing lines or the wirio, bonnet, and radiator fairing. complete the modern styling of the frontal appearance,. improvements made to the body include metal-capped sideand tail-boards, and ingenious springloaded locking rings fitted to 'ail wedges of the sideboards, which ensure that the wedge cannot fall out on the road_

The Thames chassis, complete with body and a full load of concrete blocks, was brought from Dagenham to the forecourt of the old Crystal Palace for the trials. My lest equipment was soon fitted, and with the manufacturer's representative at the wheel, the first stage was started by

the descent of Arterley Hill. This presented' a minor brake-fade test, but I noted no deterioration in braking when bringing the vehicle to a sharp halt at the traffic lights,.

Little traffic. was ,experienced When negotiating Elmer& End and West Wickham; but the. lightness of the steering became apparent when driv-'

ing through Lay ham's Farm Road, which is actually a narrow, tortuous lane approximately three miles long. After reaching the main road at chelsharn, the Thames was driven down Suceornbs Hill, and as a precautionary measure, second gear was engaged for the descent. Despite this, however, there was a tendency to overrun the.engine, and the brakes were in constant use.

Although the test vehicle was fitted with the standard ratio axle, I thought it might be able to climb the hill, so that after taking the temperature of the cooling water the test was started from the foot of the incline. First gear was engaged, and there was no difficulty in taking the short 1-in-5 hump railway bridge and, indeed, second gear was engaged as

• we passed over the bridge. This, however, was an optimistic move, and low gear was again employed, the gradient at this point being 1 in 8. The climb was continued in low gear with the engine turning over at maximum revolutions, but as the Fordson came to a stretch of 1 in 5, and an even stiffer gradient after taking the bend, the engine revolutions commenced to fall and the unit finally stalled. This was unfortunate because 10 yards ahead the road

levelled out to 1 in 15. It was apparent that, had the lower-ratio axle been used, Succombs Hill would have been conquered.

Baulked on Bug The next climb was made on Bug Hill, which whilst longer than Succombs, has a gradient slightly less severe. After taking the water temperature at the foot of the hill, I started the climb, but unfortunately met a lorry and trailer on its way down.

Because of the narrowness of the road, there was no option but to reverse the Thames to the foot of the hill, let the other vehicle pass, and make a second attempt.

On the second run I had a clear road and the Fordson literally romped up the hill in first gear with the engine turning over at maximum revolutions. A check on the water temperature showed a rise of 41 degrees to 205 degrees F., atmospheric temperature being 64 degrees F.

The brake system was given a thorough test for fading by descending Titsey Hill in top gear at 20 m.p.h , and employing the brakes to restrict the speed. Almost a mile of this treatment produced volumes of smoke from each brake drum, and then the 1-in-5 section was reached. The foot brake was fully applied, and the Thames pulled up in a reasonable distance on the gradient. As a further check, the hand brake was applied, but failed to hold the vehicle without assistance from the foot brake. Most of the movement of the hand brake was lost because of the well-heated drums, and it would have been only a multi-pull hand brake which could have mastered such conditions.

I turned the Thames at the foot of

the hill and made ready for the ascent of Titsey Hill. Temperatures were taken again and, with low gear engaged, the climb was started: There was no opportunity to change

into a higher ratio, and the full 0.9-mile climb was made on maximum engine revolutions. It took approximately 6 minutes for the climb, which is reasonable for this class of vehicle. The cooling-water temperature at the top of the hill was found to be 202 degrees F.

By this time the maker's representative expressed surprise at the number and severity of the hills in this area. A few more long gradients were encountered on the consumption trials, Which were made between Caterham and East Grinstead. The first trial was made with conditions representing long-distance haulage. The start of this test was part of an incline, and third gear was engaged for the first two minutes. After this, most of the 10 miles was covered in direct drive, with brief periods in intermediate ratios. It was a reasonable give atid take course, and although the speed, when climbing the gradients, was governed by the severity of the climb, downhill stretches and level ground were coVered observing a maxitnum of 35 m.p.h. The average speed over the course worked out at 29.3 m.p.h., and the fuel consumption figure returned was 12.1 m.p.g. Considering the nature of the course, this result is certainly excellent.

A further test, with one stop per mile, was made over the same route. This test proved the Thames to be an economical vehicle for local haulage, the fuel-consumption return being 9.15 m.p.g. To worsen the conditions of this trial. I made most of the stops on inclines, a detail which would increase fuel consumption.

There is very little level ground in the North Down area, so the acceleration and braking trials were made in the region of South-East London. I selected a quiet road, near Dulwich College, and although it was reasonably level, it had been only recently resurfaced. This proved a setback during the braking trials, and all wheels locked for several feet at every emergency application.

The resultant stopping distances of 20 ft. from 20 m.p.h. and 44 ft. from 30 m.p.h. indicate that the Thames has a highly efficient braking system, and that, given better conditions, its efficiency should be in the region of 100 per cent Because of the wide speed range of the engine, second and third gears only were used for the acceleration trials. This method produced an acceleration rate above the average for a 5-ton-class machine, from 0 to 30 m.p.h. taking 28.4 secs. Top-gear trials were not altogether satisfactory because of the distance required to reach 30 m.p.h. and a slight rise which was encountered at one end of the course, but taking an average of the trials made in both directions, it took 38 secs. to accelerate from 10 to 30 m.p.h.

This concluded the trials of the Fordson, which had covered over 70 miles during the test. I noticed, at all times during the day, that the new Thames is quieter and cooler to drive than its predecessor, and that driving visibility and steering are also much improved. Operators of this vehicle will doubtless appreciate its fuel economy and should find that fewer man-hours are required for its maintenance.

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Organisations: Earls Court, Dulwich College
Locations: London

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