AT THE HEART OF THE ROAD TRANSPORT INDUSTRY.

Call our Sales Team on 0208 912 2120

Involving Revolutionary Features in Construction, the Fabricated Body-cumChassis Light-alloy Frame

21st November 1947
Page 43
Page 42
Page 44
Page 43, 21st November 1947 — Involving Revolutionary Features in Construction, the Fabricated Body-cumChassis Light-alloy Frame
Close
Noticed an error?
If you've noticed an error in this article please click here to report it so we can fix it.

Which of the following most accurately describes the problem?

is of Noteworthy Design. Driving Comfort and Accessibility of Components are Prominent Attributes of the Jensen 5-6-tonner

By L. J. Cotton, M.I.R.T.E THE Jensen is a revolutionary vehicle, compared with others of its class, as it employs a fabricated aluminium frame, which, by virtue of its lightness, permits a low-loading platform space of 23 ft. to be used. The complete vehicle weighs less than 3 tons unladen. That this additional body space can be utilized in a variety of manners was exemplified by the various loads that I saw being carried by Jensen and other vehicles in the Coventry area.

I observed a normal 5-6tonner carrying 20 chassis frames; the next vehicle in the convoy, a Jensen, was carrying 30 frames of a similar pattern. Two drivers comparing lorry-loading notes disclosed that a Jensen was carrying a 40 per cent. greater load of deckchairs than its contemporary. These are two examples of the purpose for which the Jensen was designed—to handle larger bulk loads than other models of its class.

A study of the frame, which is a chassis-cum-body structure, reveals that the I-section members are a composite fabrication of 14-gauge sheet alloy, 16 ins. deep, riveted to top and bottom flanges of 2-in, anglesection aluminium alloy. Five cross-members of similar construction are riveted to the side-members at regular intervals. Angle-section strips of aluminium alloy, riveted to the top-section side-members, form diagonals between the frame side and cross-members. Additional strengthening plates, again of light alloy, are riveted to the frame at the rear-spring anchorages. Thus, the frame, although very light, is essentially a rigid and durable structure.

Proprietary power and transmission units are embodied in the design, the well-known Perkins P.6 70 b.h.p. Aeroflow oil engine forming the power unit. A Moss five-speed gearbox and back axle are linked with a three-piece propeller shaft which employs one

Layrub and two Hardy Spicer couplings. Self-aligning bearings support the shaft from the two centre cross-members.

In "The Commercial Motor" on September 19 was published patent No 588,948, covering the radiator, engine, exhaust, clutch and gearbox unit, which can be changed in three hours. These units are held by JNSN distributors, and when an engine change is desired the components can be disconnected and withdrawn from the vehicle in the space of 30 minutes. Replacing and connecting-up take approximately two hours, and within three hours of being removed from service the vehicle can be in use once again. The radiator grille is secured by 12 half-turn-release screws, enabling it to be removed or replaced in as many seconds. Fuel and lubricating-oil filters, located on each side of the radiator, are immediately accessible on removing the grille.

To prolong the period between servicing, a Tecalemit pressure-controlled lubricator, actuated by clutch-pedal novement, supplies lubricant to each oiling point of the :hassis.

For the purpose of our test, five concrete blocks, each veighing approximately a ton, were loaded on to the platform body. The blocks were carried on a timber ;tructure, to prevent damage to the body flooring, which consists of a square section of corrugated light alloy reinforced with timber inserts.

Having fitted the fuel-consumption measures, we backed out of the works—not an easy job with a lengthy vehicle in such a narrow and difficult exit—and carried xi to the public weighbridge. There, again, I realized the-unusual letigth -of the vehicle, as to gainaccess to the weighbridge we had to reverse across the width of the road. The excellent turning circle and light steering were .greatly appreciated in this manceuvre, and with one wheel climbing over the 8-in. kerb we reached the weighing platform. With the long chassis and 16-ft. 2-in wheelbase, I was interested to see what happened to the frame during the kerb-climbing episode, and felt almost disappointed to find no visible distortion along the body line.

At this point I took over from the works driver and proceeded along the Shrewsbury-Towcester Road, branching off at Beacon Hill to make a hill-climb. The mileometer reading was 15 when we began our journey, so that I expected the controls to be fairly stiff, but with the exception of the gear change, they were all reasonably light to handle.

Obviously, the driver received due consideration when the cab was designed. It is a spacious, light compartment, with hot and cold air vents. signal indicators, foot dimmer switch and covered pedals. The change-speed lever and hand brake are located just below the rim of the steering wheel, so that movements of these levers can be accomplished without the gymnastic actions required by drivers of some commercial vehicles. The designer, probably having suffered a long ride in a bucket-pattern seat in bygone days, has standardized an adjustable flat-squab seat in the cab, a point much appreciated by long-distance drivers. After driving the vehicle for a few miles I appreciated the comfort of the cab and its controls.

Beacon Hill proved to be a stiff climb of approximately 500 yds of a 1-in-10 gradient This gradient did not overtax the Jensen by any means, although it is B9 considered to be the most difficult bill in that area. It was climbed comfortably in second speed after having taken off from a standing start. Because of the. short distance covered, the radiator temperature remained fairly constant, being 138 degrees F at the bottom and 142 degrees F at the top. Atmospheric temperature taken during the climb was 65 degrees F.

Next, the Jensen was turned towards Shrewsbury for the fuel-consumption tests. A quick change from main fuel supply to' the measures Via& made, followed by a " warming-uP " run to the stretch of road between Brownhills and Gailey, which had been chosen for the test. A straightforward run of 10.12 miles, with two traffic stops, was accomplished in 22 rnins. 58 sees., which, after deducting 14 seconds for the two stops, gives an average speed of 26.7 m.p.h. Fuel used for the journey was 0.504 gallon, equivalent to 20.08 m.p.g., an excellent figure considering the newness of the chassis components and the load carried.

At this point, having run a fair mileage, the oil temperatures were at normal working levels. Radiator temperature was 138 degrees F.; engine oil, 155 degrees F, gearbox, 150 degrees F., and differential, 128 degrees' F. The radiator temperature is on the low side, especially with an atmospheric temperature in the region of 70 degrees F., and suggests that blanking would be beneficial in colder weather.

After changing back to the main fuel supply, a search was made for a reasonably level stretch of road for acceleration and braking tests. Unfortunately, the ideal stretch could not be found, with the result that the acceleration figures varied up to 8 seconds in tests made in each direction.

atO An average of the acceleration tests showed that 0 to 20 m.p.h. through the gears could be accomplished in 15 secs. and 0 to 20 m.p.h. in 35 secs. Acceleration in direct drive from 10 to 30 mph. gave readings varying up to 8 seconds, the averages being 10 to 20 m.p.h., 13 secs., and 10 to 30 m.p.h., 34 secs. These figures compare favourably with those of similar vehicles.

The Lockheed brakes appeared to be effective in normal driving, and this impression was fully borne out by the tests, which yielded stopping distances of 55 ft. from 30 m.p.h., and 28 ft. 6 ins. from 20 m.p.h., equivalent to 54 per cent. and 48 per cent. respectively.

Throughout the days test, I found the Jensen a delight to drive. The acceleiation and braking figures prove that it is capable of a lively, yet safe, performance. The steering is light and, of course, the sprung steering wheel forms an added luxury.

While putting the vehicle through suspension tests, ran into an S-bend, which had not been signposted, at a speed of about 45 rn.ph. With nothing worse thantyre squeal, the corners were taken on the correct side of the road and no hint of body roll was felt. This was a test I would not normally have considered fit for any commercial vehicle, but it proved the Jensen to be safe under all conditions.

It is understood that the vehicle is among the higherpriced of its class, which is not surprising, having regard to the detail design and finish. No matter which point of the body or chassis is inspected, there is no trace of shoddy workmanship or cheapness of design. I would say that the vehicle is capable of carrying up to 30 per cent. greater bulk loads than other vehicles of. a similar class, which would soon regain the additional outlay

Tags

Locations: Coventry

comments powered by Disqus