ON THE OUTSIDE LOOKING
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SEEING vehicles specially prepared for show on the stands at Earls Court and using them in service are two entirely different things. But even a quick run round can give a fair indication of how demonstration models will act in service. We had the opportunity to put seven of this year's demonstration models through their paces in typical operating conditions in West London and along M4.
Trevor Longcroft looks at lorries
There were no new model light vans or mediumweight chassis available in the demonstration areas. I selected the Foden and Dodge eight-wheel rigids and the Scammell Crusader 4 x 2 tractive unit fitted with the RR 280 power unit.
The Foden chassis is fitted with the new S80 cab and the vehicle specification includes the R-R 220 diesel engine, Foden 12-speed splitter box and double-drive bogie. The vehicle was laden to its 30-ton maximum.
Though cab space has benefited from a reduction in engine compartment height, the cab is, for me, not deep enough — the driver's seat could not be set as far back as I would like.
The inclination of the steering column may be set over a small arc, so catering for drivers who prefer to sit either over or behind the wheel.
All the gauges are displayed on a panel ahead of the driver — a point I favoured was the positioning of the speedometer and rev counter which were clearly visible through the steering wheel. The speedometer is large and could be replaced by a tachograph without alteration to the panel. Steering presented no difficulties even in confined spaces.
The pedal controls are nicely positioned and, except for the clutch, pleasantly light to operate. The clutch pedal was stiff and required too much travel.
Initially the gearbox was quite mystifying but once the change sequence had been determined, and I had a little practice, smooth, effortless changes were easily accomplished.
Some of the adjacent ratios are rather close to each other and so some gears can be omitted in the change sequence. For instance, from 3rd underdrive the up-change was to first direct — missing out fourth underdrive. In traffic the half gearchange actuated by the pre-select button on the gear lever and a de-clutch were useful to keep the vehicle moving with minimum effort.
The Dodge/Unipower eight-wheeler, a Unipower conversion of the KT900 6 x 4 tipper chassis, is fitted with the Perkins V8.510 diesel engine, Chrysler six-speed synchromesh gearbox and Eaton twin-speed double-drive bogie. The vehicle was loaded just over its 28 tons gross maximum.
The standard Dodge cab is fitted to the demonstration chassis. The gauges are positioned on a panel in front of the driver, the speedometer is located to the left side of this panel and is partially obscured by the steering-wheel rim.
The driving controls, pedals, steering wheel, gearlever and the manually operated park/emergency brake control are conveniently placed. The brake control seems to have been added as an afterthought. It looked rather out of place, protruding from the floor in front of the dashboard.
The 1611 8in. wheelbase Dodge came into its own when driving in heavy traffic. I was able to negotiate tight corners without any fear of clipping traffic bollards. Close quarter manoeuvring proved a little fatigueing, the steering effort required, in my view, being excessive. However, effort reduced with increased speed and for general town road work I considered the rim effort to be reasonable.
The six-speed synchromesh gearbox was positive and light to operate — the unfamiliar driver will have no trouble getting to grips with this box.
The .Scammell Crusader 4 x 2 tractive unit, one of the few 32-tonners available for test, is fitted with the R-R 280 turbocharged engine. Apart from the engine and wheelbase, the vehicle specification is that of the longer wheelbase BRS version tested in CM in 1971. The vehicle was unladen.
Since the CM test Scammell has endeavoured to brighten the internal cab appearance, criticized as "drab" in the CM report.
The roof and sides are now neatly trimmed and plain paintwork on the dash has been replaced by a simulated woodgrain finish.
The park brake control has been removed from the dash to the left side of the driver's seat.
Generally speaking, the cab was quiet; conversation between the passenger and driver could be easily heard. To reduce in-cab noise, Scammell has modified the engine hatch area to provide a better seal against engine noise.
As expected with an unladen vehicle, the ride was rather bouncy and, unless one restricted the speed, adequate control of the vehicle was not possible.
Steering effort was minimal and control precise; the wheel is now dished and gives more knee-room when de-clutching.
I liked the positioning of the clutch, brake and throttle pedals, but I would suggest that Scammell fit a rubber pad on the clutch to prevent any foot-slip.
The Crusader, coupled to a 36ft-long platform semi-trailer, has obvious handling disadvantages in busy streets. Nonetheless, the effortless gearchange, light steering effort and well-placed rear view mirrors allowed adequate time to check all quarters when negotiating corners, etc.
Martin Hayes went on the buses
I was able to drive four passenger vehicles from the Earls Court demonstration park at this year's Show.
The Ford R1014 coach with Plaxton Panorama Elite III bodywork I drove featured a number of detailed improvements to chassis and 45-seat body. The biggest single new feature is the use of a Holset turbocharger which reduces the noise level when compared with earlier Ford psv chassis using the turbocharged 360 engine.
I found the six-speed all-synchromesh gearbox — another new feature — a little daunting at first and I think that it would require some time to become fully familiar with its intricacies. With the vehicle unladen 3rd gear proved quite adequate for level-road take-offs. It was the change from fifth to fourth which seemed to cause most trouble.
I was impressed with the coach's lively feel and 70 mph was a perfectly easy motorway cruising speed. This feeling was enhanced by the excellent power steering (now fitted as standard) which required no conscious effort to maintain the correct line at high speeds. Set in Plaxton's restyled dash board instrumentation was both adequate and easy to red. Some of the banks of rocker switches could be difficult to find for the unfamiliar driver, however.
The Volvo B59 with Marshall Camair 47-seat bodywork was a familiar vehicle to me; I had driven it in Scotland last month (CM September 1). The big difference, though, was that it was loaded then. It was immediately clear on setting out from Earls Court that there were a good deal more rattles with the vehicle empty. These were by no means unacceptable but were still more prevalent than on some of the bus's competitors. Engine noise also seemed higher than on the Scottish run. This may have been due to a badly fixed engine access panel but the layer of sandbags which had been used to simulate a load had obviously damped out a great deal of noise. The main complaint was the high-pitched turbocharger whine when moving quickly in the low transmission ratio. It was also possible to identify several areas in the body where wind noise was generated.
These comments made — which all relate to body deficiencies which can presumably be remedied — it must be emphasized how impressive the chassis itself is. Ride—which I rated as superb on the Scottish trip — was still excellent with the vehicle empty. The steering lock of over 60 per cent was really useful when manoeuvring and driving controls, other than the roof-mounted air wiper knobs, are well positioned.
The Seddon Pennine Inter Urban express bus first made its appearance at the Brighton coach rally earlier this year but Earls Court was the first chance I had to ride in it and drive it. Undoubtedly the most important new feature of this bus is the fully automatic four-speed Allison transmission (an optional extra). Allied to the turbocharged Perkins 6.354 engine, the gear box gives imperceptible changes of ratio. Unfortunately other features of the vehicle are not so praiseworthy. Engine noise during acceleration is quite unacceptably high for passengers in the front three or four rows of seats, not to mention the driver. Idling in gear with the handbrake applied — the natural procedure at traffic lights, for instance — produced such vibration that the exterior mirrors were ineffective until the accelerator was applied. The standard power steering is very vague and strong concentration is required to maintain a straight course at speed.
The body itself has a commendably flat floor with very easy passenger access and is quite rattle free. Ride was acceptable for an empty vehicle.
The last vehicle I drove was a brand new model. Its chassis, the Mercedes 0.608D, has not been available in the UK before, and its Charterway Coachcraft 29-seat timberframe body was new, too. At £5950 the coach is a strong competitor in the revitalized midi class.
With a maximum speed of 64 mph and a cruising speed of about 50-55 the coach felt a little undergeared. The Mercedes engine feels capable of pulling a higher ratio without any fuss. At present there is rather too much noise at the front end at speed despite the five-speed gearbox.
The front end scuttle is the traditional Mercedes design and power steering is standard. For my taste this suffers from the common complaint of being too light, and a little vague about the straight-ahead position.
I was particularly impressed by the progressive brakes (despite an empty vehicle), the ventilation system and the good ride. Visibility was above average with the exception of a badly positioned offside mirror. This will be moved, I was told.