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Better at 38 than 32?

4th April 1981, Page 37
4th April 1981
Page 37
Page 38
Page 39
Page 37, 4th April 1981 — Better at 38 than 32?
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ESIGNED to operate at 40 nnes, if the Armitage Report is ieded by the Government, the to-axle tractive unit will be rescted to 38 tonnes which will be ell within its capabilities.

Three engine options are tailable for the 1628 Roadtrain, e most powerful of which is ..yland's own TL12 turboiarged Flexitorque diesel.

Though both the Cummins 1240 and the Rolls-Royce 265L -oduce more than the legal iinimum power requirement of hp/ton for operation, even at tonnes neither should present serious challenge to the TL thich has a gross rating of 10kW (270bhp) and gives an istalled output of 20 3kW 7.70bhp) to provide a power to reight ratio of 5.3kW/tonnes 7.2bhp/ton) as tested here.

Turbocharging is a way of laking an engine more efficient, nd Leyland claims that reviions in its turbocharging techniues has led to slower and more ven combustion rates to give a imilar output, but at ten per cent lower engine speed.

Reduced peak loads are intended to lessen wear and tear, so improving durability and re liability. The light twin countershaft design of the Spicer SST10 ten-speed splitter gear box contributes to the tractive unit's kerbweight overall which.

although with a rest cab anc plated for 40 tonnes, is stil lighter than most with more con. ventional day cabs at 38 tonnes.

A sleeper cab version was an nounced at the 1980 Commercia Motor Show and is now in pro duction, but as yet not availabl( for test. Like most sleeper cat models, it requires an extensior for the maximum permitter length to couple legally to a 12n (40ft) trailer.

The cab's shape gives opti mum clearance, and woulr allow coupling with inches ti

spare using any of the thre, fifth-wheel positions of 483mn

(19m), 535mm (21in) or 610mn (24in) and a kingpin position e 1,200mm (48in).

Entry into the cab itself prE sents no problem. Grab handle are placed within easy reac from the ground, and two wid steps are staggered so that the can be easily seen from insid the cab whether getting in c out.

Rounded corners soften th cab's profile, while overall d mensions disguise the roomy ir tenor where the two seats al separated by a low carpeted ei gine cowl, on which a conso houses the gearshift lever.

A small steering wheel, adjus able for rake, sits above the e most clinical dashboard, hou ing a very neat ar comprehensive instrumei continued overlm panel. The park brake and heater controls are also housed on the facia.

Stowage space is lienited to header rail shelf, which has a deep back lip to contain the oddments put there, a good-sized glovebox with a lid on the mate's side, and the central 3onsole with a box lid in which :o keep delivery notes and such ike. The space behind the seats mill also accept an overnight Dag .

Shades of grey and charcoal or trim and carpets may appear a little drab at first, but it's easy )n the eye and shouldn't show he dirt too quickly. A firm cloth:overed Chapman suspension ;eat gives plenty of adjustment, Jut only experimentation with ill the levers will find the most :omfortable setting. To put up he bunk, the seats must be noved forward and tilted.

Forward visibility is unimmired by the header rail, while he bottom edge of the front creen is located well below acia level.

The opportunity to drive Thicies heavier than 32 tons toes not happen too often but he ease with which the 1628 iandled 38 tons was very )leasing. As expected, acceleraion is marginally slower than vhen we tested Roadtrain at 32 cins, but only when moving way from rest did this become pparent on the road.

During normal A-road running was not difficult to keep Ioadtrain moving at a speed in eeping with other road users. op gear at 40mph corresponds 3 about 1,300rpm on the tahometer, just above maximum ngine torque.

On the motorway sections, a peed of 60mph could be mainlined for long spells. During the wrney north along the N18, earchanges were rare even ver Shap a drop of only one Dg was needed.

Inevitably, it is the A68 section etween Rochester and Nevilles ross which proves both the latching and operation of the earbox. Using the splitter, ownchanges can be made very uickly, so avoiding any loss of npetus on hills. Gearshift enagement was reassuringly potive and gearchange could be rade more quietly than using re preselector.

The close ratios of the indidual gears often allowed an ctra gear to be snatched as the -adient eased a little on stiff imbs.

The impression of an excep tionally firm ride may have been influenced slightly by the setting I had chosen for the suspension seat. Anti-roll bars fitted to both front and rear axles kept the vehicle on an even keel. On this test there was no evidence of cab nod — a point of criticism during our 32-ton tests. But Leyland denied making any changes to either the cab or vehicle suspension.

In-cab noise levels were low. We recorded readings of between 73.5dBA at 40mph and 77.5dBA at 60mph. The Government is already committed to reducing external noise from 91 to 88dBA by 1983 for vehicles with engines rated above 200bhp -Sir Arthur Armitage proposes 80dBA by 1990. Because the decibel scale is logarithmic, this reduction of about 10dBA is equivalent to halving the noise level — which should prove a daunting prospect for vehicle manufacturers.

Leyland has already achieved a great deal with the use of sandwich insulation material in selected areas beneath the trim and underfloor coverings, including double-skin construction in the most vulnerable areas of the floor and bulkhead.

Fuel consumption of 43,7 lit/100km (6.46mpg) is over 1.25mpg less than CM achieved when Roadtrain was tested at 32 tons (July 5, 1980) coupled to a flat-bed trailer. A better comparison would be with the 40-tonner group test run with Al's triaxle tilt trailer (CM, October 25) in which the route was similar to that of our Roadtrain test.

Roadtrain matched Ford's HA4432 which had the besi overall journey time in our 40tonner tests and only the Foder Fleetmaster equipped with E Rolls-Royce 290L bettered T45'E fuel consumption figure in thai test, but was much slower des. pite the power to weight ratio: being closer.

A five per cent difference ir the weights would be expecte( to reflect more in the journe) time than the fuel returns.

On a one in six gradient a MIRA the park brake held thr vehicle facing both up an( down. A facia-mounted lever I; unusual, but became mon acceptable as the test continuer over the three days.

On a one in five incline with i bootful of revs and a feather Ilk feel on the clutch, the vehicli just managed to restart. Th, park brake, however, only hell when facing down the slope.

The service brakes, spree, over five axles, gave shor stopping distances and hig peak deccelerations withou locking any of the wheels on dry road surface.

Both engine power to weigF ratio and the matching of th driveline components made fc easy tireless driving.

All controls and instrumenti tion are well-placed and easy t use and read, although the gea box splitter control is exceptior ally noisy. The overall desig plays down the large powerfl Marathon-type image, yet ii ternally the T45 is room enough.

Careful selection of the majr cornponents contributes to a lo kerb weight, which adds to tl. payload potential. The TL12 e gine is the only choice at th weight until Leyland is press rised into making the mo powerful Cummins and Roll Royce engines available.

The Armitage proposals cr bring benefits to the vehic operator, but may yet gin manufacturers some headachE

Below: Roadtrain 'S non-aggress, lines complement its aerodynar appeal.

Tags

People: Arthur Armitage
Locations: Nevilles, Rochester

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