Leyland Redline Boxer 16-ton-gross two-axle rigid
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by Trevor Longcroft ALTHOUGH not having as much horsepower as most other 16-ton-gross four-wheelers tested by CM, The Leyland Redline Boxer for this weight put up an acceptable performance on our 731-mile operational trial. With only a little over 19hr running time needed for the test, average speed was 38.2 mph. And the test vehicle
gave excellent fuel consumption results-11.4 mpg—which was slightly better than the 14.25-ton Boxer also with the Perkins 6.354, tested in early spring last year; bad weather and different drivers were the probable reason for this.
On brake tests the BX1600 gave first-class results, like the lighter weight Boxer and its stablemate the 16-ton Mastiff when these were tested. As expected, acceleration times were below the normal standard, but well-selected overall ratios from the Turner gearbox and Baton two-speed driving head in the rear axle helped give the Boxer an acceptable performance on the road. Similarly, the gradient ability of the vehicle was not impressive. But while not giving the performance associated with its higherpower stablemate the BX1600 gave a more than reasonable account of itself over the hills of A68.
The Redline Boxer BX1600 is in effect a Mastiff 16-ton-gross vehicle with the Perkins V8 510 diesel engine replaced by the lower-rated Perkins 6.354. This engine gives 117 bhp BS net at 2800 rpm. And transmission raids are altered to suit the change of power and torque available. Apart from these points all features of the BX1600 are common to those of the Mastiff. Steering is power-assisted by an Hydrosteer ram and the Westinghouse full air-braking system incorporates spring brake chambers on all four wheels. Also as the Mastiff, the clutch has air-assisted hydraulic operation.
The drive from the Turner SA3018 five-speed synchromesh gearbox on the model is through a 13in. single dry-plate clutch. The gearbox used on the test vehicle was not the standard gearbox; second, third and fourth ratios being 4.10, 2.19 and 1.17 as compared to 4.38, 2.40 and 1.48 of the standard box.
Supplementing the five-speed gearbox, the •BX1600 has a Leyland axle with an Eaton two-speed driving head, to give 10 effective forward gears. Progression through the gears is from low to high up to third gear and then the sequence follows fourth /low, fifth /low, fourth/high, and fifth/high; a sequence not uncommon these days with two-speed axles. The two-speed rear axle fitted had ratios of 6.14 /8.38 to I. the ratio change being made by an electrically operated pneumatic system.
The cab is the same as the Mastiff being all-steel construction. It is a tilt cab and approximately 5min was needed to gain access to the engine. A large inspection cover located under the passenger seat can be removed for accessibility to the fuel injection equipment, etc, and for routine maintenance; this was removed in less than 2min.
The route for the operational trial and tests was completed in two days, a stop being made at the Motor Industry Research Association's testing ground at Nuneaton on the first leg for acceleration, brakes and gradient tests. For the tests, a payload of 10 tons 19.5cwt was carried bringing the gross weight to 16 tons 2.25cwt; extra weight was accounted for by two passengers in the cab and ancillary test equipment carried.
While expecting a rather poor performance compared to the Mastiff, I was soon pleasantly surprised by the Boxer. On the first leg of MI—to the A428 turn just beyond Watford Gap—the Boxer maintained an average speed of 51 mph reaching its maximum of 59 mph for much of the run. The run on AS and then on M6 was uneventful; traffic was average and there were no hold-ups and good time was made in excellent weather to the Forton service area. Here 17.7gal of fuel was added returning a fuel consumption of 11.7 mpg for the first 207 miles. This figure improved on the figures obtained by other vehicles of this weight tested by CM.
Behaviour of the BX1600 over the difficult part of the first day's run, over the Tweedsmuir Hills gave no reason to suggest that there was an inadequate performance from the test vehicle. On various long gradients fourth/low or third /high were necessary to maintain progress but the truck returned a commendable average speed of 33.4 mph.
It was over the steeper sections encountered on the second day that the relative shortage of power became apparent. It was necessary to select first/high for many of the gradients encountered on A68 and first now on the steepest. This is reflected in the average speed of 22.4 mph from West Woodburn to Consett.
Fuel consumption, however, remained comparable with the figures obtained on the earlier motorway sections except for the section between Rochester and Consett where there was an abrupt reduction to 7.7 mpg,
For the run home down Al and MI the BX1600 experienced very little difficulty. It laboured in fourth /low up the long gradient of the M18 between the Doncaster by-pass and M1 but once on the motorway the Boxer was again able to maintain an average speed in the order of 50 mph, running up to 59 mph on many occasions. Average speed between Scotch Corner and the Doncaster by-pass was upset by a 3.3-mile detour through Boroughbridge that took 9min to clear. Had Al been clear an average speed slightly in access of 36 mph would have been possible for this part of the test_
Handling of the Boxer became progressively more a pleasure than a chore as the trial proceeded. The brakes responded in an efficient manner to foot valve pressure and the -fed" of the brakes gave confidence after only a few applications. Tests at MIRA echoed the confidence on the braking system when a stopping distance of 43ft--better than Mastiff—with a peak efficiency of 74 per cent was obtained from 30 mph in dry conditions. Acceleration through the gears showed the Boxer to be slower than the vehicles of the same gross weight tested by CM. This was noticeable on the road also; especially when a quick pick up of speed was required for overtaking.
Acceleration tests in direct drive were made with the 6.14 axle ratio engaged and while this gave extended times, no complaints came from the transmission while picking up speed from 10 mph.
Restarts on the 1 in 6 gradient at ivIIRA were only possible in first /low. A first /high restart was tried but the Boxer did not have enough power to pick up speed to maintain a climb. A reverse flow restart was managed on the 1 in 5—a first /low attempt facing up this slope failed—and the parking brake held the laden vehicle in both directions on the 1 in 5 gradient.
At first I could find little to criticize with the ratios in the gearbox and wondered why the unit in the test machine was not to be used as the standard. But as the test progressed I felt that the third and fourth gears could have been closer than they were. This is in fact so on the standard gearbox that will be fined. Changing axle ratios was straightforward and neither myself nor John Bell of Leyland Scotland had any trouble in effecting a good axle change. Ratio changes throughout the synchromesh gearbox were good, difficulty occurring once or twice in the lower ratios where it was possible to beat the synchromesh in a quick change from third to second.
General handling of the 16-ton-gross Boxer was not at all difficult_ Steering tended to be on the heavy side, but an initial impression that the steering would require too much attention was dispelled after the first few miles. With use, the steering became easier and the vehicle maintained the required course with the minimmn of concentration and little effort_
Clutch control was excellent. The action was positive and the fed was similar to that of a simple hydraulically assisted system; the Boxer has a Clayton Dewandre air-hydraulic clutch actuator, the same as the Mastiff_
Driving at 40 mph the noise level in the cab was acceptable and normal conversation could be heard_ Speeds in excess of 50 mph, however, cowed the noise level to be raised to a relatively high level and normal conversation was difficult, although the BX1600 was quieter than some 16-ton-gross vehicles tested by CAL
Angular adjustment of the driver's backrest combined with seat height and leg room adjustments provided for a comfortable driving position. Soft and well-damped springs gave an excellent ride with little or no tendency to roll and contributed to an extremely smooth ride.
Instrumentation is adequately covered in the Boxer by a speedometer and temperature, fuel, battery charge, al, and air gauges mounted on the central facia. Direction-indicator and light switches are mounted on either side of the steering column, all other switches being housed in a moulded console situated above the windscreen on the driver's side.
The opening rear window is retained for
this Boxer (it has been dropped for some trucks with the same cab) though I would think it is rarely used. To do so increases the level of cab noise and allows the various engine fumes/smells and heat to enter the cab. As with the Mastiff, the air-operated parking brake is conveniently located to the right-hand side rear of the driver's seat.
Mirrors fitted to the test vehicle were of the convex type (not standard) and they gave excellent rearward vision. Only one criticism could be made of them and that was their location. When the passenger leaned forward or lowered his head, vision through the nearside mirror was obscured. Perhaps this can be easily rectified by repositioning the mirror bracket.
The Redline Boxer required very little "looking after" and I arrived at the Hemel Hempstead end of the trial, reasonably fresh and pleased to find such a contrast to some of my first impressions of the vehicle.
By any standards the operational trial can be considered most arduous. And an operator buying a vehicle to operate on hilly routes such as A68 has the option of the Mastiff powered by the Perkins V8.510 diesel engine (179 bhp gross). While performing satisfactorily over the route, the BX1600 would be considered ideal for less hilly routes or areas of a flatter nature such as East Anglia, where the power available from the Perkins 6.354 diesel engine would be ample.