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Robustness and Refinement

18th September 1953
Page 45
Page 46
Page 47
Page 45, 18th September 1953 — Robustness and Refinement
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HAVING had experience in the overhaul and maintenance of heavy vehicles at a time when ;olid-rubber tyres were common, and nspection covers were provided in he crankcase to permit of the idjustment of the oil troughs for luring lubrication, 1 have always leen a staunch admirer of practical ind well-built chassis. Every vehicle lut up for road test is scrutinized to ;ee what provision is made to proiide accessibility in maintenance, vhilst uncommon details in design tre also looked for.

I therefore appreciated many 'eatures embodied in the Guy Wolf 2-3-tonner, powered with the

Perkins .four-cylindered oil engine. The specifi

cation includes such items as an 11-inchdiameter clutch, cast aluminium radiator with detachable top and

bottom. tanks, and a

double drag link in the steering. The latter, although adding to the number of moving parts and lubrication points, ir instrumental in lightening the steering effort at any point of the lock, and road shock at the wheel is reduced.

Although the Wolf is robust, it carries no superfluous weight when assessed by its contemporaries, the 13-ft.-wheelbase chassis weighing 2 tons In cwt. when fitted with a coa,chbuilt cab and sturdy 15-ft.-long body. As indication of the general construction, the main frame members are swept up over the rear wheels and taper in towards the front. The full-depth cross-members are attached by fitted bolts.

The chassis is notably free from oscillation even when the engine is idling. The power unit mounting comprises an annular rubber member with saddle behind the gearbox, and Metalastik units at the front, which also control torque reaction. Refinements in the transmission include constant-mesh to the third ratio, and Layrub couplings to both sections of the divided propeller shaft. During acceleration tests, using top gear from 8 m.p.h., the take-up in transmission was smooth and devoid of rattle.

Other components are, in keeping with the general refinement of the Wolf, this applying to the suspension, steering and braking system, the latter being very effective without employing a servo. The standard coachbuilt cab is unusual in the amount of space, semi bucket-type seats and interior trimming. To quote a small detail I noticed, the accelerator pedal is provided with a roller-type pad, and the electric unit of the windscreenwiper is remotely mounted to avoid putting the motor in a position where it might restrict visibility.

With just under 3 tons payload, the weight distribution between axles was quite good, but the total weight with crew was above the 5i-tons gross vehicle weight recommended by the makers for optimum performance. Although the 6.50-20-in. tyres are standard, a slightly higher than normal final-drive ratio of 5.7 to 1 is provided, so giving a. governed, speed of just under 40 m.p.h. in direct drive.

After weighing the Wolf at the works, it was driven • to Galley on the A5 trunk route, for initial tests. As a warming-up .procedure, the brakes were tried .first, using equipment loaned by the ,Road Research Laboratory to measure stopping distance. The apparatus comprised a light-alloy magazine loaded with chalk pellets and small explosive charges, each being connected in turn to a Six-volt dry battery and pressure-operated switch, the latter being attached to the brake pedal pad. There is no measurable time delay in this equipment, and after checking speedometer accuracy the test was started.

The results were remarkably consistent, the braking • system .being found very efficient, although the Tapley meter which was also used varied by 13 per cent. with, identical stopping distances. All wheels could • be locked with an emergency application, the tyre marks being slightly heavier for• the rear wheels. The stopping distances of 21 ft. from 20 \ m.p.h. and 48 ft. from 30 m.p.h.. are well above the 0.5g retardation normally obtained with full load. Tapley readings rang,ed from 70-83 per cent., and with over 50 sq. in. per ton brake frictional area when carrying the advocated payload, the Wolf should be consistent in its braking. Adjust ment or replacement of the brak facings should be spaced at fair] long intervals.

The acceleration rate was norrna with no time saving shown by star ing from rest using low instead c second gear. It took 36 sec. to reac

p.h. passing through the gears, approximately the same time top gear engaged from 10-30 s As previously mentioned, the ear performance was notably ;11.

the ensuing consumption trials, uy showed .that refinement can -ered without prejudice to fuel my. First came a one-stop per test over a 7-mile circuit as :entative of local work. The

was fairly level, and apart starting away at each point, was no further need for the ct ratios. I added 3.05 pints of ) the test tank at the end of the t, which corresponds to 18.33 , the average running speed 25.3 m.p.h.

Ti followed a 48-mile out-andconsumption trial, embracing level to moderately undulating d on the A5 route between the )ek side of Gafley to Shifnal, Ling some hills on the road to iorth. Apart from two delays ifnal on the outward run, the vas completed without further ince.

: gearbox ratios appeared right neral operation, and third gear with the demands imposed by inclines. There was only one mn after leaving Bridgnorth on turn leg, where second gear was ed for any period longer than ring frequently used this route nsumption trials, I have noticed he return leg of the course is severe, which reflected in the tive fuel returns. For the Guy, nsumption rates worked out to m.p.g. and 21.95 m.p.g. for the runs respectively, the small :nce between the two being indicative of ample power for all conditions. The average speed over the 48-mile route was 27.4 m.p.h.

While at Bridgnorth, at the turning point of the first consumption trial, I continued into the town to tackle the Hermitage as a combination of hill climbing and heating test.

During the normal running, the radiator water reached 147° F. against 64° F. ambient, indicating that the makers have left ample margin for operation. in warmer zones. . The Hermitage is a stiff climb which, for the Wolf, required the use of second gear for 3i mm., and 30 sec. in the lowest ratio. This work raised the water temperature by 12° F.

As a final test of climbing performance, I drove to Old Hill Tettenhall, where there is a slope of 1 in 8 for over 100 yards, and a maximum sec tion of 1 in 5. According to the makers, the chassis is rated to climb a 1 in 4+ gradient when loaded to 51 tons gross. From the ease with which the vehicle was started on the 1 in 5 gradient when loaded to 5 tons 124 cwt., I would assess their claim as having a good safety margin. After my day's work with the Wolf, I consider the same remark could be applied to the entire vehicle.

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