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INTERNATIONAL TRIAL OF AGRIMOTORS
By Our Agricultural Correspondent
BY reason of extreme pressure on space in last week's issue of The Commercial Motor it was found necessary to hold over a portion of my commentary on the World Tractor Trials ; I left off during a description of activities on the second day.
To continue, I saw the German Lanz-Bulldog semi-Diesel tractor, which, on the first day, was working not far from the Marshall Diesel machine, in the same field, and after wards had several opportunities for inspecting it. The machine is a four-wheeler with single-cylindered engine starting by blowlamps and running on Diesel oil.
The H.S.G.S. is another single-cylindered semi-Diesel appliance, this one originating in Hungary, a machine with a big noise as well as a long name, and an electric headlamp for night work. The other two tractors are of 'Swedish manufac• tare, namely, Munktells, both having
two cylindered engines; the normal rating of one is 15-22 h.p. and of the other 200 h.p.
No criticism can be levelled at the work of either Diesel or semiDiesel machines,which was quite as good as that of any other tractor; there were no forced stops, nor any mechanical trouble.
Both the A.G.E. products an(1, if I may say so, especially the Aveling and Porter, appear to me to be sound propositions. From engineering and agricultural st an dpoints, they perform thorough work and B44 are neat in appearance, as well as being handy. Reduction of vibration is of great importance in. the making of a Diesel land tractor. Taking a brief survey of the three types, namely, paraffin, petrol and fuel oil, it may be said that for the most part they acquitted themselves well in the demonstrations and in the tests. In the latter some evidently failed to do justice to themselves (some would have done better after further running-in), although the demonstrations were quite satisfactory_ Three machines were withdrawn from the official tests. These were the Fordson, on account of a cracked cylinder, probably due to faulty casting ; Peter Brotherhood (A.G.E. product), on account of damage to piston, connecting rod and splash guard, probably owing to the
loosening of a nut in the crankcase, whilst the Vickers was withdrawn on account of a change in the programme of the manufacturer. The Fordson afterwards took part in the demonstrations at Ardingtnn, but the Vickers and the Peter Brotherhood did not.
PARAFFIN MACHINES. —A summary of one part of the official report clearly gives the positions of the three types. All the paraffin tractors are of the wheeled type and they differ little in general design ; all are models in regular production and each is well known, at least in the country of origin. Generally speaking, this group represents the type which, during the past few years, has been seen at work in this country. As regards weight, the larger tractors are lighter in proportion to their power than are the smaller ones.
PETROL MACRINES.—In the petrol group one agrimotor was of the ordinary wheeled type, seven were track-layers and two dual-purpose tractors, designed for road as well as agricultural work (Latil and Citroen-Kegresae). The petrol agrimotor has not yet been largely employed in this country, although a few are now in the experimental stage. There was not a great deal to choose between them as regards fuel consumption. This, it is stated, may have been due to the fact that five of the 10 machines were of Caterpillar make.
The Best Fuel Performances.
One interesting feature is that the Rushton and the Austin, which gave the best two fuel performances in the petrol group, gave a worse result in the paraffin class. Actually, in each case the engine of the petrol agrimotor is the same, except for the compression ratio and carburetter, as its counterpart in the paraffin category, which points to the fact that indifferent carburation was the main cause of the higher fuel consumption of the Austin and Rushton in the paraffin group.
In considering prices, the official report states that it is not fair to include the Latil and the Citroen-Kegresse. Obviously this is so, for the price of a machine that is virtually a lorry as well is bound to be higher than that of a machine used purely for land work. The two machines which entered for the road tests, the Latil and CitroenKegresse, may here be specially mentioned, seeing that for the land tests they were included in the petrol class.
In each ease the test consisted of hauling a loaded trailer over about 30 miles of public road, the weight of the load being decided by the owner. The actual burden chosen does not necessarily bear any definite relation to the maximum load which the machine could haul. The results are :— Latil: gross load hauled, 10.3 tons ; total distance, 28.5 miles ; total time of journey, 1 hr. 52 mins. ; average speed, 13.3 m.p.h.; total fuel consumed, 23.5 lb., equalling 3.14 galls.; fuel consumption, 93.5 ton-miles per gallon. "'CitroenKegresse : gross load hauled, 4 tons ; total distance, 28.5 miles; total time of journey, 2 hrs. 25 mins. ; average speed, 11.8 m.p.h.; total fuel consumed, 25.5 lb., equal to 3.42 galls.; fuel consumption, 33.3 ton-miles per gallon.
The route chosen, the same in both cases, inclimen a: gradient of 1 in 13. The higher set of gear ratios was used over the whole route, except for about 100 yds. on the above gradient. Throughout the test the performances of both were satisfactory.
Diesel-engine-equipped Tractors.
FuEL-ort MAcfayEs.—In the fuel-oil group the appliances were all of the wheeled type and fall into two classes, namely, semi-Diesel, or hot-bulb engines, and proper Diesel .units. During recent years semi-Diesel tractors have been.oceasionally seen in this country and are well known on the Continent.
In the case of the full Diesels, the fuel consumption in the official tests showed small variation, which is the more surprising as the machines are generally in the experimental stage and four different types of engine were represented. Fuel costs are considerably less than in petrol and paraffin machines, but the cost for lubricating oil is higher, as is the capital outlay. The weights per maximum drawbar horse power are higher. Semi-Diesels do not show much variation in price per rated drawbar horse power, the average figure being below the mean for the petrol machines, and does not greatly exceed that for the paraffin group.
The Americans did best in the official tests, the honours., so far as one gathers from the figures contained in the tables, going to the Case, the Massey-Harris and the International, including the Farmall.
A good day's work 'was done on Wednesday, the weather being fine until the closing-down of operations at about 4.30 p.m., when rain "again set in. There is little doubt that the demonstrations gave a good impression of the capabilities of the agrimotors in the different classes.