Rolls-Royce Oil Engine in E.R.F. Twin-steerer
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First Use of Rolls-Royce 133 b.h.p. Unit in Vehicle
• in Britain: Many Design Changes in E.R.F. Range
ANEW version of their existing twin-steer, six-wheeled chassis. powered by a Rolls-Royce C4.NFL four-cylindered oil engine, .Will be exhibited on the stand of E.R.F., Ltd., at the Commercial Motor Show.. This is the first example in this country of a road vehicle being powered .hy. this robust 133 b.h.p. unit, and the chassis, designated the 46TSRA, 'is rated for a gross weight of 17* tons solo or 281 tons with trailer.
Other new features to be shown by E.R.F., Ltd., include an improved Model LKG44 9-ton-gross chassis; an uprated version of the 44G: a 10-speed gearbox with air-operated auxiliary section for the 66RA overseas tractor: power steering on the 680 eightwheeler, and changes in the steering gear, hand brake and air-cleaning equipment which are common to most chassis in the range.
For Mime or Export
The 46TSRA has a similar specification to the standard 66TSGE export model, twin-steer, six-wheeler with air brakes, but the Rolls-Royce engine is alternative to the Gardner 6LW oil engine normally fitted, Although exhibited in export form, this model is available on the home market, the braking system then consisting of Clayton Dewandre-Girling air-hydraulic equipment.
The Rolls-Royce engine is an 8.1-litre direct-injection unit and its maximum power is developed at 2,100 r.p.m. The maximum torque of 366 lb.-ft. occurs at 1,300 r.p.m, The engine specification includes a twin-element lubricating-oil filter, variable-speed .governor on the fuel-injection pump, and 24v. electrical system.
A 16-in.-diameter, single-dry-plate clutch is used with a David Brown 557/24 five-speed gearbox. This has a direct-drive top gear and a low gear of 7.92 to I ratio. The box is mounted as a unit with the engine, the complete assembly being carried on four rubber mountings. The fully floating overhead-' c12 worm-drive rear axle has S'1-in. centres and gives a reduction ratio of 7.25 to 1.
As British hand brake regulations do not apply overseas, the Show exhibit will have a hand brake acting on the rear axle only. The controlled-release
hand-brake mechanism employed 'on E.R.F. vehicles for several years has been modified slightly on this and all other current chassis.
The pawl which coitrols the brake application is now 'tripped automatically when the'level is pushed fully forward across the ratchet. This ensures that there is no risk of the two pawls of the complete mechanism becomii tg fouled and thereby locking the system.
With a 17-ft. 6-in. wheelbase, the chassis is suitable for 20-ft. bodies. The overall length is 23 ft. 7 in., and the maximum width is 7 ft. 101 in. with 11.00220-in. (14-ply) tyres, these being fitted as standard. The high power-toweight ratio afforded by the Rolls-Royce engine makes the 46TSRA eminently suitable for long-distance work, either solo or with a trailer, in countries such as Australia and South Africa. '
The 1.1(G44 6-(on chassis has been modified extensively. Girling two-leading-shoe hydraulic brakes with internal wheel cylinders are now fitted, and instead of the hydraulic continuousflow powered system previously used, a Clayton Dewandre vacuum servo is installed. The facing area has been increased with the adoption of new Girlituz units. A straighter propeller-shaft line has been 'obtained by lowering the engine and redesigning the mounting arrangements. Swinging links are retained at the front, but a single Metalastik bush is used at the rear.
This mounting necessitates a lug on the top of the bell housing of the David Brown gearbox, which is mounted as a unit with the engine. A torque reactor is fitted to the left of the engine', and a double-acting hydraulic damper is used on the opposite side.
Wider Front Track
Greater stability and a better steering lock have been obtained by using a wider front track, whilst the standard rear axle is now an Eaton 13,500 twospeed unit. This has an electrically operated change mechanism. A new type of rubber mounting for the propeller shaft is fitted to this chassis.
The cab of the LKG44 and of the 44SG tractor with Scammell coupling has been redesigned to bring it into line with the larger cab used on other E.R.F. chassis. The wrap-round windscreen now consists of two panels, whereas previously four panels, incorporating glazing bars at the corners, were used.
Plastics is used for the first time by E.R.F. in the construction of the cab. The roof panel is a one-piece moulding. with two built-in longitudinal ribs, and the centre section of the front grille is a plastics fabrication with metal brightware retaining the familiar E.R.F. grille.
Four-wheeler Uprated
The 44G four-wheeler with Gardner 41_,W oil engine is uprated to 13 tons gross. In doing so, a larger vacuum servo has been fitted, an Eaton 18,500 two-speed rear axle has become standard equipment and the rear brakes have been altered. These alterations include the use of larger power,cylinders, with high-angle wedges to increase the shoe-lift and reduce maintenance; and the provision or facings I in. wider, 151-in. by 6-in, units now being supplied.
On all versions of the 540 14-tongross four-wheeler the wheelbases have been increased to bring the weight distribution between front and rear axles to a ratio of 5 to 9. These.. increases are proportional to the original wheelbases of the three 540 chassis. Aeon hollow rubber springs are fitted as auxiliary units to the rear axles of all 440 and 540 chassis. These act as helper springs and bump rubbers with full load.
The new Fuller R-960 Road-Ranger 10-speed gearbox is a feature of the 66RA prime-mover. This chassis was introduced at the 1954 Show, and is powered by a Rails-Royce C6.NFR six.cylindered oil engine. This 'unit was recently uprated from 184 b.h.p. to 200 b.h.p. at 2,100 r.p.m.
The Fuller gearbox is of American manufacture, sold in Great Britain by Automotive Products Co., Ltd. A fivespeed version was fitted to the 1954 Show chassis, and the new box is basically _similar, with the addition of a large two-speed auxiliary gearbox at the rear.
Synchromesh engagement, using disc clutches instead of cones, is provided for the auxiliary gears, and engage ment is preselective, the operation being by an air-pressure cylinder on the side of the box. The control consists of a small handle attached to the gear lever, linked by cable to an air valve on the box.
The gears in the auxiliary box are large because of the full multiplication of torque provided by the main gearbox ahead of it. The box gives ratios of 3.54 and 1 to 1, and the overall range afforded by both boxes is from 7.43 to 1 to 0.78 to I.
Running -at a gross train weight of 40 tons the 66RA has a maximum speed of 38 m.p.h. and a gradient
ability of 1 in 5. A Clayton Dewandre air-operated exhaust brake is fitted to the Show chassis. This has -amanual control on the steering column.
Power-assisted steering is now offered on E.R.F. eight-wheeled chassis, and a 68G will be seen equipped with it. The Mantes hydraulic system is used, the valve gear being mounted above the 861-type cam-and-double roller steering box. The power cylinder is anchored to the frame and the piston rod acts on the steering relay lever. A Plessey hydraulic pump is driven in tandem with the dynamo of the Gardner 6LW power unit.
On all models except the LKG44 and those equipped with power steering, a new tapered steering column tube is fitted. The rigidity of this tube has made'it possible to dispense with a stay between the cab and the column. This is of particular importance because of the relative movement between the column and the flexibly mounted cab.
Oil-bath air cleaners are to be fitted to all E.R.F. chassis. A position behind the cab front panel in front of the passenger sea t h as been chosen. The cleaner is therefore fully enclosed, with the result that induction noise in the cab is eliminated. Air is admitted through the side section of the grille motif and from below the floor, whilst , access to the cleaner is given b5,1 a detachable panel in the cab.
On any E.R.F. home-market chassis with air-hydraulic brakes, the Gardner power unit is fitted with a BendixWestinghouse Tu-Flow air compressor. This is mounted on the right of the cylinder block, at the front. In this position it has been found to reduce the air flow past that side of the engine and, combined with the heat from the exhaust system, which is also on the right of the engine, this has made drivers uncomfortably hot. A cowl is, therefore, now .fitted to direct the flow of air from the fan along the hot side of the engine.