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ONE OFF THE OP SHELF!

9th July 1954, Page 38
9th July 1954
Page 38
Page 39
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Page 38, 9th July 1954 — ONE OFF THE OP SHELF!
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Which of the following most accurately describes the problem?

By

L. J. Cotton, M.I.R.T.E. THE driving comfort, degree of visibility and general good

. qualities available in the new E.R.F. 8-tonner, are outstanding. So far as running economy is concerned, I have yet to meet another. rigid 8-tonner that will give a fuel return of over 19 m.p.g. when carrying a full load, and 26-27 m.p.g. when running light.

When the KV-type cab, with curved windscreen, heater, demister and other coach refinements was introduced at the Scottish Show last year, it was considered by many as being possibly a premature break from conventional design. After spending a full day on the E.R.F. Model 44.G with this cab fitted, I realized why this assumption has proved to be wrong, and the reason for the vehicle so quickly receiving all-round approval.

Such a vehicle is good publicity for the operator, because its styling is outstanding, and the shapely cab offers scope for using a well-blended body. The performance is up to the customary E.R.F. standard, and a great advance has been made in fuel economy by reducing weight and using a two-speed axle.

In its driving characteristics the vehicle tested was as near perfect as any I have yet met in this country or overseas. The resiliently mounted cab with a wide screen and devoid of corner pillars at the front, is noticeably effective in reducing driving fatigue. As an illustration of this, during the consumption test the speedometer indicated 40 m.p.h. which I mentally assessed as being at least 30 per cent. optimistic.

Without warning the driver, I B4

checked the instrument over a known distance against a stop-watch, and found that the speedometer and mileometer were accurate. In comparison with the conventional cab having a normal flat screen and pillars, objects on, and adjacent to, the road are seen earlier and for longer periods, which is tantamount to lessening eye strain.

Noise and heat insulation have been reduced to a new low level, because the engine-cover panels are made as frames to take 1-in.-thick felt, which is also lapped over the hinge and joints. As the screen is set in rubber and not openable, the heaterventilator is an essential for attaining a comfortable cab temperature in winter or for admitting a generous supply of cool air in hot weather.

Other private car refinements include a Chapman's Leveroll driving seat, which is independently adjustable for height and distance from the steering column, leather trimming and plush draught excluders, an ashtray and a Polaroid sun vizor. Every effort has been made to lessen driving fatigue by placing the controls within comfortable reach, and consider the E.R.F. has reached the optimum for effortless longdistance operation.

The windscreen is also much deeper than normal, this being achieved by tapering the frame side members below the cab, so that the radiator and engine can be mounted lower in the chassis. In effect, the frame is deepest in section immediately behind the cab, and then takes the form of a parallelogram with the top face tapered towards the front, and the lower part progressively reduced in depth to the rear crossmember.

Normally, cross-members are arranged at all spring-anchorage points, but this is not necessarily required in a wide-frame unit, such as the E.R.F., where the springs are attached directly below the side members. With this arrangement, there is no tendency to " pincer " the frame at the spring brackets, and

there is no cross-member adjacent to the rear-spring hangers.

The design enables weight to be reduced without sacrificing strength. Furthermore, the wide spring-base adds to the stability of the vehicle on the road.

The Gardner 4LW four-cylindered oil engine gives 75 b.h.p. at 1,700 r.p.m. and 237 lb.-ft. torque. A David Brown 0.45 five-speed gearbox, with an overdrive-top ratio of 0.75 to 1, is fitted, and the clutch is the new Borg and Beck Model 13AS. I3-in.-diameter unit, with a solid centre plate.

There has been an alteration in the engine-gearbox mounting. Whilst the twin toggle links are retained at the front, the rear end now has two adequately spaced Metalastik Meta

cone units, which also control torque reaction.

A Layrub coupling at the front of the two-piece propeller shaft prevents low-speed chatter, and the centre hearing is housed in an aluminium

casting with rubber bushes on each side of the bearing, the assembly being secured with angle brackets to a cross-member. The electrically operated two-speed axle has mediumrange ratios of 5.62 and 7.8 to 1 which, with the overdrive gearbox and 9.00-20-in, tyres, provides a maximum speed of 46-47 m.p.h., and the ability to climb steep hills with an 8-ton payload.

The chassis supplied had an 18-ft.long timber-platform body attached directly to the frame through alternately spaced wood and light-alloy cross-bearers. Loading height is thus reduced by dispensing with the conventional body runners, which are normally needed with outboard springing.

When weighed without payload, the vehicle registered 4 tons, indicating that, for taxation purposes, it would be about 3 tons 17-i cwt. Six large concrete blocks were added, representing a payload of slightly under 8 tons, but with test equipment, a driver and two observers in the cab, the gross weight was 12 tons 31cwt., giving the equivalent of a full 8-ton payload with a crew of two.

First, there was a 32.4-mile fuelconsumption circuit, which started at the works and included a fairly easy run through Middlewich and Northwich, followed by trunk-road work through to Mere corner, Cranage and Holmes Chapel back to Sandbach. It was left to the works tester to set the pace for the course, and I expected some cautious driving to conserve fuel.

Travelling with a stream of traffic, the pace was kept to about 30 m.p.h. into Middlewich, speed being increased slightly after negotiating 86 the town. From Northwich the wide trunk road was free of traffic, and I soon noted the speedometer needle hovering over 40 m.p.h. It was here. that I checked for instrument accuracy.

There were periods when the E.R.F. was cruising at 43 m.p.h., but from engine noise and other normal standards, it did not appear to the observers to be travelling at more than 30 m.p.h. It was almost uncanny that in a cab-over-engine oiler, travelling at over 40 m.p.h.. we were able to talk without unduly raising our voices, and that the predominant noise was the wind whistling past the doors.

It is said that the streamlined cab has reduced wind resistance and

helped fuel economy at high speed. After observing this test at Sandbach. in which the return was 19.18 m.p.g. at 32.8 m.p.h. average speed, I am prepared to believe that this claim is justified.

The trial was fairly straightforward, with only five stops on the circuit and few checks by slowmoving, heavy traffic. The E.R.F. in giving over 19 m.p.g. on a fast run with an 8-ton payload sets a record that will be difficult to equal.

Short performance trials followed, but later in the day the load was removed and a second run made over the circuit to assess the fuel-consumption rate when operating light. Slightly more traffic was encountered on this trial, but the gradients on the route were negotiated more easily, and an average speed of 35.3 m.p.h. was returned.

By this time, I was becoming accustomed to the E.R.F. covering 32 miles in under an hour. It took only 9.7 pints to refill, affording a return of 26.7 m.p.g. The makers claim of 26-28 m.p.g. without load is not exaggerated, because with more restrained driving, the result I obtained could be improved upon. In addition, there is the initial friction of a new chassis to be considered, and after 10,000 miles the engine and transmission would be more freerunning.

Acceleration and braking trials were made alongside the canal between Elworth and Middlewich, where the road is reasonably level and has an average tarmacadam surface. With a Clayton Dewandre 6.87-in, servo and Girling hydraulically operated two leading shee braking system. there is ample assistance to the manual effort on the pedal, and the frictional area of the facings-480 sq. in.—ensures effective retardation.

Excellent Retardation I locked all wheels from 20 m.p.h. with an emergency brake-test, and in the measured stopping distance of 28 ft., the tyre skid marks were 15 ft. long. By selecting a stretch for these trials where the road surface was better, the stopping distance was reduced slightly, and it was apparent that the E.R.F. lacked nothing in its braking performance.

The acceleration trials indicated that the vehicle was about average. From 0-30 m.p.h., using the higher ratio of the axle and second, third and fourth gears, took 40.5 sec. With the lower ratio of the axle engaged, there was a slight improvement up to 20 m.p.h., but the overdrive was required to reach 30 m.p.h. and ultimately the average time again worked out to 40.5 sec.

Hill-climbing Characteristic

To wind up the day's work, there was a hill-climb test at Winsford. where, from a standing start, the lorry was headed up Wharton Hill. which has an average gradient of 1 in 10 and a maximum section of 1 in 8. This was climbed comfortably in low second gear, and a stopstart test was afterwards made using the same ratio. A 1-in-8 gradient is about the maximum which can be taken in second gear when starting from rest.

It was with some reluctance that I parted company with this " RollsRoyce " of the heavy commercial field. For the operator who is anxious to sustain the goodwill of his drivers, there is no better vehicle. In addition, it will gratify his business instincts and add not a little to his prestige.

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