OVER 10 TONS ON •
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FOUR WHEELS
BY taking advantage of the high strength-to-weight ratio of aluminium_ twice that .of steel—the development department of the British Aluminium
Co., Ltd.; has designed a maximum-load four-wheeler with a payload capacity approaching• 104 tons. This outstanding achievement opens a completely new field in four-wheeled goods vehicles and will be seen in public for the first time at Earls Court next month on the Mann Egerton stand.
Albion Motors, Ltd., who supplied the running components, have given great assistance to the designers during the design and initial construction periods at the Mann Egerton works at Norwich. The vehicle is called the Mann Egerton Albion and is similar in mechanical layout to the standard Albion Clydesdale 14-ton-gross chassis in 16-ft. 111-in.-wheelbase form.
The essential difference between the Mann Egerton vehicle and the Albion is in the unladen weight. Whereas the Albion chassis, without cab or bodywork,
weighs approximately 3 tons 7 cwt., the complete British Aluminium platform lorry weighs little over 3+ tons.. Semi-integral construction and the fullest possible use of aluminium and its alloys account for the considerable weight difference, which has been obtained without any sacrifice in structural strength Or repair facility.
for a gross weight -of 12 tons and was a fully integral
design with a 5.5-litre underfloor engine. Much has been learnt from this original design, particularly in respect of stresses and strains in the main structure, but a different approach was obviously necessary for a 14-ton-gross lorry.
For instance, a forward engine position was needed to ensure that the rear-axle loading did not exceed' 9 tons. At the same time it was decided that to give a variation of body styles and to make it possible to repair the outer body sections in the event of damage, they should be bolted to the inner body components and main framing. This form of construction would also allow 8-ft.-wide bodywork to be used if the unladen weight of the complete vehicle exceeded 4 tons.
Greater Economy The advantage of the British Aluminium design is that it is now possible to carry a clear 10-ton payload on two axles, whereas until now three axles have been necessary. This leads to far greater operating economy in respect of payload ton-m.p.g., besides secondary economies, such as reduced tyre wear and improved fuel consumption when running unladen.
A further point is that as all the running components are of Albion manufacture, the vehicle can be included in a fleet of that make without introducing nonstandardization, and the resources of the Albion spares and service organization throughout the world can be used.
The backbone of the Mann Egerton-Albion is th,e -main frame section. This is constructed throughout of NS.6 quarter-hard alloy, Argonaut welding being used principally, with Argonarc for short runs, The two deep longitudinal members are pressed from /-in. material. Their great depth aft of the cab gives a large strength margin and provides a normal floor loading height.
There are 12 diaphragms, it-winding the rear crossmember, plus two tubular 'cross-members between the rear spring-hanger brackets and the front engine mount
ing tube. The diaphragms are pressed out from c16 *-in, plate, and most are rectangular in shape.
Two members are extended downwards at the centre-line to carry the two bearings of the three-piece propeller shaft, and these and two other deep members which are cut away for gearbox clearance have T-flanges welded to their lower edges. The upper edges are folded over at right angles, as are both edges of the other diaphragm members.
Other than the front engine-support tube,. the rear engine-mounting brackets and the spring-hanger brackets, which are of steel, the complete frame structure is of aluminium alloy. The ferrous items are bolted to the frame, and the longitudinals are reinforced with 1-in.-thick aluminium plates at the springbracket mounting points.
The frame was assembled without the use of jigs, being merely built up on trestles, but when it was completed it was found that no distortion had taken place. This serves to indicate that the welding processes used had not set up internal stress within the assembly.
Positive-grip-pattern (P.-G.-P.) treadplate is used for the floor of the 20-ft.-long platform body. The centre plates are bolted directly to the main longitudinals and diaphragms, but the side sections are welded to tapered outriggers. Each complete side assembly is then bolted to the main frame, the outriggers coinciding with the diaphragms to give the effect of straight-through crossbearers. A standard British Aluminium section is employed for the side rave rails, whilst the headboard, which is of flat sheet with a welded-on flange, is attached directly to the main frame by vertical channels.
Albion 115 b.b.p. Engine The Albion oil engine which powers the lorry is the EN.286 four-cylindered direct-injection unit. This develops 85 b.h.p. at 2,200 r.p.m., with a maximum torque rating of 225 lb.-ft. at 1,200-1,300 r.p.m. Its capacity is 4.88 litres, and it carries a 11i-in.-diameter single-dry-plate clutch. The standard Albion five-speed constant-mesh gearbox is used, and the engine-gearbox unit has a four-point mounting, with sprung bell-crank levers at the rear and rubbers at the front.
Although the engine and gearbox are perfectly standard, the radiator. is definitely not. This unit is a lightweight all-alloy assembly manufactured specially by Delaney Gallay, Ltd. It is of the still-tube type and the header and bottom tanks are bolted to the tube plates, so that they may be detached for cleaning. The complete radiator has been Pyhuninized throughout as a protection against corrosion. Its weight is 28 lb., which represents a saving of at least 50 per cent, over a conventional copper unit of equivalent capacity.
. A three-piece propeller shaft takes the drive to the Eaton two-speed axle. The axle is a new unit known as the 16,500 Mk. III and has ratios of 5.62 and 7.81, with an electrical change mechanism.
The Mk. HI axle is similar to the standard 16,500-unit in respect of torque capacity, but a heavier casing and larger bearings make it suitable for a 9-ton loading. The theoretical maximum gradient ability is 1 in 5 (20 per cent.), whilst the maximum speed, neglecting overrun, is 45.5 m.p.h.
A standard Albion front axle is used, and the suspension employs conventional heavy-duty semi-elliptic c17 springs. Mantes cam-and-double-roller steering gear is fitted and the Girling brakes are actuated by a Clayton Dewandre vacuum servo. The front brake drums measure 161 in. by 31 in., whilst the rear axle carries 151-in.-diameter drums, the facing width being 6 in Weight reduction has been carried even to the wheels, and the vehicle is believed to be the only goods carrier to run in Great Britain on forged-aluminium wheels, certainly in recent years. As they are not yet being manufactured in this country, the Mann Egerton-Albion lorry has American Alcoa three-piece alloy wheels. These carry Michelin D.20 tyres on 7.5-in, wide-base rims and have offset. Production wheels to British Standards would have 6-in, rims and 51-in. offset.
Alcoa lightweight wheels have been in use in the U.S.A. for over three years, and give a saving of approximately 40 lb. per wheel over conventional steel units. They have machined rims to give optimum tyre seating, and apart from their advantage of light weight, the good heat dissipation properties, of aluminium ensure maximum conduction of heat from the tyres and brake drums. Reduction of tyre heating is proportional to reduced tread wear.
Aluminium alloys have been used extensively in the construction of chassis ancillaries, such as the fuel tank, vacuum reservoir and battery carrier. The cab is an all-alloy assembly, Consisting of NS.3 unpainted embossed sheet riveted to a frame of HE.10 extrusions.
The cab design embraces a full-width, wrap-round windscreen, and a flat, full-length engine cowl. The embossed panels are unpainted because scratches do not show on their irregular surfaces and glare is not caused, so paint is considered superfluous. Relief is provided by the polished radiator grille and decorative headings. These are made from super-purity aluminium, which takes a good polish and has a high 'resistance to corrosion. Brytal treatment gives this alloy a finish equivalent in brightness to that of chromium plate. This latest British Aluminium project is more than a mere design exercise; its possibilities are large, even to the extent of making the lightweight rigid six-wheeler obsolete. Production in platform-lorry and other versions is contemplated by..Mann Egerton and Co., Ltd.