Mechanical Tendencies
Page 71
Page 72
If you've noticed an error in this article please click here to report it so we can fix it.
Revealed by the Royal Show
A General Advance in the Design of Tractors and the Increased Use of Compression ignition Engines are Two of the Outstanding Items.
NOW that the Commercial Motor Exhibition at Olympia is a biennial affair, the Royal Show provides one of the best annual indications of tendencies in the design and construction of vehicles for various phases of transport work. Naturally, the number of exhibitors at any particular Royal Show is somewhat restricted, but the vehicles shown reveal new developments in practice.
At Harrogate one of the most striking tendencies was the increased use of the compression-ignition engine in vehicles and tractors of all kinds. It must be realized that in this .country not only is crude oil cheaper than petrol by a considerable margin, but it is at even greater advantage in overseas lands. Suitable fuel for burning in steam vehicles is often at a prohibitive figure abroad, or altogether unob
taivable. As the market for transport machines in Great Britain must obviously be limited, it behoves makers to seek other fields for sales. Therefore the Diesel engine bids fair to be adopted in many new designs.
Typical of the tendency to adopt crude-oil engines for agricultural purposes were the new Garrett farm tractor and the McLaren track-laying and wheeled machines. Possibly the largest exhibit embodying an engine of this class was the Fowler-M.A.N. 150 h.p. eable-ploughing engine ; whilst some Barford and Perkins rollers, a McLaren, mobile winch, a Marshall roller and a Ruston and Hornsby roller also utilized this form of prime mover.
It was clearly indicated in many. of the tractor exhibits that the needs of the agriculturist are being more thoroughly studied by the makers of these vehicles. The ability to turn in a confined space was strikingly demonstrated in the case of the Rushton tractor, with its reversible front axle.
thus giving a choice of two, wheelbases, whilst one of the new Case tractors bad its engine set laterally in the f iame, thus reducing the wheelbase very considerably.
In the direction of fitting appliances to tractors to meet special needs, there was a generous display of items of interest, both to the farmer and the general haulage contractor. Such designs as the International crane with buffers at each end, the Fordson with a shovel attachment, and another tractor ofthe same make with a powerdriven mower on the off side of the machine come to mind. The convertible, agriculturaltype Rushton' which had wheels designed to run upon hard roads or soft plough land, revealed an appreciation of a problem which has long faced the agriculturist. .,.
A demonstration of a four-wheeldrive Lath l tractor, showing that it is capable of surmounting objects in its path at a slow rate of travel, was convincing to a large number of potential buyers. The fact that this machine can be converted from ordinary pneumatic tyres to traked wheels in a matter of a few moments was of marked interest to those engaged in such tasks as beet haulage.
Signs are not wanting that research work is proceeding apace with infinitely variable gears of a foolproof description that are suitable for use in road vehicles, and amongst these the new
Robertson gear on the Kerr Stuart Diesel-engined locomotive appealed to many. Although a frictional principle is employed so far as the contact between one member and the flywheel is concerned, the development of " flats " is4prevented by designing the gear so that the driven disc engages rapidly with the flywheel, the necessary slip being taken by a secondary plate clutch. The gear-change mechanism on the Howard light locomotive is operable by unskilled labour.
A new type of Foden under. type steam wagon made its first appearance. This is a six-wheeler with a three-way tipping body. The engine is placed horizontally across the frame and arranged to give a very simple form of drive from the crankshaft to the worm-driven rear axles. The boiler is of the water-tube type and the working steam pressure is 250 lb. per sq. in.