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The DAF FT2800 DKDT/ Dithers 32-tongew artie
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\vricillATfisi-NAArr 12/74
by Graham Montgomerie; pictures by Dick Ross
THE DAF 2800 Series for Europe offers a choice of four versions of the company's 11.6-litre engine naturally aspirated or turbocharged, coupled either to a ZF or Fuller gearbox. The first example to be made for the British market is the DKTD which uses the turbocharged engine and the ZF 6-speed splitter gearbox. This was first shown at the tipper conference in Blackpool earlier in the year when I had the opportunity for a short teNt run. To follow up those brief impressions, Commercial Motor has just completed a full-scale operational trial of the big DAF with very favourable results.
Performance
The DKTD engine develops 184kW (248 bhp) which is well over the 6 bhp ton standard and this meant that for normal road use second low was used for starting. The performance of the DAF under full acceleration could only be described as lively, the only problem being the time required to move the gear lever across the gate.
The DAF recommended practice is to split every gear, eg second low, second high, third low and so on but, in the lower gears especially, the engine came on the governor almost as soon as the gear had been engaged. I think the actual times achieved on the acceleration straights at MIRA would have been reduced if whole changes had been used.
The gearshift pattern of the ZF AK 690 is the mirror image of a standard layout. with the low gears towards the driver and the high gears away from him. This is because of the change to right-hand drive, but I found no difficulty with the arrangement.
On the motorway the vehicle would cruise effortlessly at the sixty limit and it returned a fuel consumption of 2.4 km/1 (6.8 mpg) on M6 between Forton and Gretna. The tortuous section between Rochester and Nevilles Cross which incorporates the two I in 6 gradients at Ridsdale and Riding Mill was covered at an average speed of 47.6 km/ h (29.6mph) for a fuel consumption of 1.56 km/ I (4.4mpg).
The Riding Mill gradient was the only occasion on the whole road section when first gear was required (high ratio) — even Ridsdale was climbed in second low. Flexibility is one of the engine's strong points and it would pull strongly from around 1,000rpm.
From previous CM road tests for 32tonners, the overall fuel consumption for the complete route averages approximately 2.30 km/ I (6.5 mpg). The DAF averaged 2.37 km/1 (6.7 mpg) for the test which has previously only been bettered. by the 2,200 from the Dutch company. The real eye-opener from the consumption point of view was the phenomenal figure of 3.82 km/1 (10.8 mpg) returned on the Al section at the constant 40mph speed limit.
The I in 6 and I in 5 test hills at the MIRA proving ground were negotiated easily and the 2800 only just failed to restart on the 1 in 4. In fact by being more brutal with the transmission I think it would be just possible to restart on this gradient but as we had approximately 800 miles.to cover on the road I decided against a further attempt. The effective handbrake held the laden vehicle on the 1 in 4.
Braking
The brakes were not the best feature of the big DAF. Although the retardation figures were acceptable they were not as good as I expected. In common with other 32-ton artics recently tested there was too much braking effort going through the drive axle with the result that I consistently locked up the latter leaving heavy rubber marks with no obvious effects from the trailer.
I am convinced that these braking distances would be trimmed down with a different brake balance. On the road the brakes were powerful and hence reassuring with an easy progressive action which was appreciated in heavy traffic.
Ride and handling
The DAF steering was one of the best I have tried at this weight. Most powersteering systems diminish the effort required but still remain precise in action when taking a corner but then defeat the object by being rather vague in the ahead position. The 2800 was remarkably easy to control on a straight-ahead course with very little movement of the wheel being required. The ride was excellent on all types of road surface.
On the section from Pathhead to Jedhurgh the state of the road during the present reconstruction is a severe test of any truck suspension but the DAF came through with flying colours.
In-cab features
The most obvious feature in the cab is the large steering wheel, which, from the driver's point of view you either like or you don't. I personally have no strong views on this but I did find that it got in the way when reaching for the minor controls. The indicator and headlamp flasher stalks, for example, were situated just out of reach of my fingers and I had to lean forward each time to operate them. The pedal layout is good but I thought the clutch pedal was rather floppy in use.
It is very much a driver's cab and I would be surprised if there were any serious adverse comments about the comfort when the 2800 comes into service. The sleeper cab is incredibly roomy although this means that, like the products of most other manufacturers, it is impossible to couple the sleeper version to a 40 ft trailer and still stay within the legal maximum length. The mates seat is adjustable in every conceivable direction and is fully reclining besides but I wish DAF would fit a foot rail on that side of the cab. It certainly needs one.
The noise level at cruising speeds was very low. In fact at a constant 64 km/ h (40 mph) it was practically non-existent. Even when working hard up a long gradient the engine noise is kept at a commendable level. One surprising point concerning engine noise was the complete lack of any turbocharger whine even near • the maximum rated engine speed. The test vehicle was fitted with a stereo radio and it was possible to listen to this comfortably when cruising at the maximum motorway speed limit.
General impressions
Summing up the DAF 2800 DKTD, it was one of the most impressive commercial vehicles I have driven. Its performance was good and its fuel consumption was lower than average for this weight range. One point troubles me, however, which has nothing to do with the vehicle's performance. The frontal aspect of the cab is rather belligerent in appearance and, although I like it, perhaps the general public might think it is a bigger vehicle than it actually is. Certainly we attracted many hostile glances going through built-up areas, and I can't help wondering which approach is the correct one — the Daimler-Benz idea of designing a cab with good interior dimensions but which looks relatively small externally, or the DAF approach of providing an "impressive" cab which really looks its size. The price of the 2800 DKTD in the UK is £9,775.