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TRANSMISSIONS

7th May 1971, Page 58
7th May 1971
Page 58
Page 59
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Page 58, 7th May 1971 — TRANSMISSIONS
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Which of the following most accurately describes the problem?

by Paul Brockington, miMechE

3. geared for export

MATCHING a transmission to the power unit and to operator requirements is inescapably a compromise based on expediency. But the wise vehicle manufacturer will not seek durability and reliability concessions in the specification of the transmission system for a vehicle destined for arduous operations overseas.

In recent years UK manufacturers have wisely given top priority to providing transmissions that will last, but despite the wide variety of operating conditions for which a particular export model may have to cater the necessary compromise in matching has, typically, afforded a near-optimum performance, with due regard to driver ability and temperament.

Although drivers in newly developing countries are often slow learners when it comes to understanding the finer points of gear changing and timing, they are not alone in needing expert and patient instruction. The difference between the proper use of the gearbox (and clutch) and maladroit handling can be the difference between profit and loss from operating the vehicle.

Playing safe Reports from operators in newly developing and developed countries overseas are in line with the claims of a number of UK operators that instructing a driver in the basic mechanics of the gearbox and its functions relative to the power unit often justifies employing a more complicated close-ratio type of transmission. However, playing safe is frequently the best policy and this normally takes the form of specifying a wide-ratio gearbox that gives a big increase in power when down changes are made, which appeals to many experienced drivers with a conservative approach to their job. And for some applications the wide-ratio. box is unbeatable.

Vehicle manufacturers report that the recommendations of overseas distributors are a reasonably sure guide to the most appropriate transmission to fit to a chassis, the extent to which the weight and speed regulations of a country are observed by operators being often of greater importance in approving a transmission than the terms of the regulations.

Catering for extremes of misuse is best left to the man on the spot. But the world trend towards bigger haulage companies with qualified fleet engineers is creating more opportunities for vehicle makers to co-operate with technicians having a thorough knowledge of local conditions and practices, who can assess the value of a vehicle's features with regard to short-term and long-term productivity.

Furthermore, there is evidence that these engineers typically regard the availability of a suitable gearbox of a well-proven type as the most important factor in the choice of a vehicle given that the power unit is acceptable. Fortunately there is also evidence that vehicle makers are taking their advice to heart without hastening too quickly.

Benefiting from American technology may be regarded as a worthwhile and sometimes necessary expedient when designing or equipping a vehicle for export, and a number of UK makers specializing in heavy vehicles are employing gearboxes of American origin, some of which are now made in this country. This can be commended as sound practice particularly when a maker is faced with competition overseas from vehicles produced in America and on the Continent having similar or comparable transmission systems. As noted in the first article in this series there are advanced types of multi-ratio range-change gearboxes in the UK pipeline that will undoubtedly contribute to the export potential of UK vehicles in due course.

What's wanted The photographs in this largely pictorial review of UK vehicles employed by overseas operators and of export models made in this country is a random selection that exemplifies the diversity of transmissions available for diverse operations. "Random" is the operative word. Many forms of assessment are based on random checks these days. And if this selection is only part of the story it shows that UK makers and their distributors have a very fair idea of what's wanted in the world and the resources to supply it.

One or two vehicles with automatic transmission are included in the selection for good measure. Automatics will be the subject of the last article in the transmission series.

1. A Leyland 13209 six-speed overdrive gl box is fitted to this AEC Mandator/Mu 20-ton-gross attic, the tractive unit being of 35 that are now in service in South Ko The vehicles are operating on the Seoul/Pu Super Highway with the type of semi-tri vans shown in the photograph or with a flatsemi-trailer.

2. This Ox 4 tractive unit is one of many Atl son vehicles employed by Australian petrok companies to deliver fuel to service sere in end around Sydney. The torque of Detroit Diesel 290-bhp two-stroke dies4 transmitted through a Fuller Roadranger speed gearbox to a Kirkstall rear bogie.

3. Taken under an unnaturally oven Jamaican sky, the Atkinson Borderer in photograph is equipped with a Gardner 61 diesel, David Brown 6.500 six-speed gear and Kirkstall driving axle. it is operated Munns Yellow Trucking Ltd of Kingston, Munns semi-trailer is seen being loaded machinery for earth satellite communions stations.

Mit in Australia for the Shell company for rations in Queensland, this Atkinson 8 x2 er chassis is powered by a Detroit Diesel IN engine which is coupled to an Allison Series fully-automatic gearbox. Having weight frame members it has a tare weight tons 9cwt 2q r.

Eight of these Atkinson long-distance

I trains are operating on the tortuous 0-mile run from Darwin to Alice Springs in tralia. The power of the Cummins NTC ,ocharged 335 bhp diesel is transmitted to uller Roadranger RT012B 13-speed gear

he 10-speed fully automatic trans non of this Leyland Hippo three-axle le-mover transmits the torque of the 200 bhp diesel to the heavy duty double-drive bogie. Having a length of 63ft the machine carries 17,600gal of aviation spirit for refuelling Jumbo jets at Schipol airport, Holland. Struver AG of Hamburg built the tank.

7. The versatility of the Foden 12-speed splitter/range-change gearbox is shown in this photograph of a cattle train, taken in Australia, which is hauled by a Foden tractor equipped with the transmission and powered by a Cummins 310 diesel. A planetary type of splitter/range-change unit is a feature of the box.

8 and 9. The ability of SCG semi-automatic gearboxes to withstand severe usage is exemplified by a Scammell Contractor photographed at the Peko Mines, Northern Territory, Australia. The vehicle is powered by a Cummins NT 335 diesel (8) and by a Con tractor operated by United Africa limbers in West Africa which is powered by a Cummins NH 250 engine, the gearbox in both cases being an RV 30 eight-speed unit Equipped with a side tipping body and hauling three side-tipping trailers, the mines vehicle has a gross train weight of 120 tons.

10. Employed for TIR operations between the UK and the Middle East, this Scammell Crusader is seen being coupled to a United States Lines semitrailer with refrigerated container. the gross weight of the outfit being 44 tons. The Detroit Diesel 8V71N 287-bhp power unit drives through a Lipe Railway dutch to a Fuller Roadranger RTO 915 15speed gearbox and thence to a double-drive bogie with differential lock.

11. A Thornycroft six-speed gearbox and hubreduction double-drive rear axles are features of this Guy Big J 45-ton tractive unit that was recently exported to the company's Jamaican distributors, the power unit being a Cummins NHK 220 diesel. The unit is being used to haul a low-loading semi-trailer carrying heavy construction equipment.

12. Bangkok. Thailand, is the scene of operations of this Nai Led Bus Company's Leyland Comet bus that often carries up to 80 passengers at rush hours on inter-city and suburban routes. It is one of 40 similar vehicles that are powered by a Leyland 370 115-bhp diesel and is equipped with an Albion GB 241 five-speed constant-mesh gearbox. 13 and 14. Bodied by Ciscar of Zaragoza, Spain, for operations in Las Palmas, Canary Islands, this bus 113) is based on a Seddon Pennine V chassis that is powered by a Perkins rearmounted 6.354 diesel and fitted with a David Brown five-speed constant-mesh gearbox. It is one of four Pennine IV and Pennine V models recently dispatched to Las Palmas, the Pennine IVs being fitted with a front-mounted engine. A Pennine IV chassis 114) is seen being loaded on an artic at the Seddon works for transport to Dover.

15. Seen being loaded with crushed metal for building the Napier Taupo Highway in New Zealand, the Leyland Hippo tractive unit in this photograph hauls a tipping semi-trailer carrying a payload of 16 tons over a very hilly route. The transmission comprises a Leyland five-speed constant-mesh gearbox from which power is transmitted to a Leyland hub-reduction rear axle.

16. Christmas Island in the Indian Ocean is the destination of these Leyland Super Hippos. They are equipped with a Leyland seven-speed crawler/overdrive gearbox and a double reduction rear axle. The Edbro 15 cu yd dump bodies are heated by the engine exhaust and tip to an angle of 71:kieg.

17. Awaiting export to Johannesburg, South Africa. these Shelvoke and Drewry self-compacting refuse collectors are mounted on Leyland Super Comet Eland chassis equipped with a Leyland 401 138 bhp diesel and a seven-speed gearbox providing overdrive and a crawler gear. 18. Photographed before dispatch to Jord this ERF 66 RR220 tractive unit is powered Rolls-Royce Eagle 220 bhp diesel and is equi pad with a Fuller RT015 15-speed gearbox at Kirkstall BGT bogie. The outfit is one of me being employed on a contract for cern& phosphates.

19. A Fuller RT0909A nine-speed overdril transmission is fitted to this ERF A.64CU3: tractive unit that is destined for Belgium. It powered by a Cummins NTK 335 diesel al the Kirkstall D85 rear axle is of the hub-redu tion type.

20. Equipped with a David Brown 6.500 si speed overdrive gearbox the ERF 64CU2o tipper/dumper in this photograph is power by a Cummins NHK 205 diesel, the Kirkst axle being of the double-reduction type. T vehicle is destined for Ghana.

21. A 15-speed gearbox—the Fuller RT09 transmission—is fitted to this ERF 66CV2 tractive unit that was photographed befo leaving for India. it is powered by a Gummi NH 220 diesel, while the Kirkstall bogie is the hypoid-geared type.


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