. TRACTOR NOTES.
Page 21
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IMUST BRIEFLY cOnclude the notes of my impressions of the recent trials, and of the con: elusions which those trials help to confirm. I have not hitherto written anything about the transmission. There is, as a matter of fact, little to be haid. As to the manner of it, there can be -little doubt in the minds of any who have had an engineering training but that totally-enclosed gearing must be the final form. This conclusion 'has already been reached by more than one manufacturer. The speed is determined by ploughing conditions. At present, with the style of cultivation in vogue, 2i miles per hour is most suitable. Anything Much fastet than that fails to out the type of furrow which is most desired in this country. I am well aware that, advanced thinkers are of the opinion that present methods of cultivatibn will shortly go by the 'board, and that the broken furrow which high-speed ploughing causes, and will cause in most soils, whatever the design of plough, will be helpful in that it will speed up the aeration of the soil so that earlier preparation of the seed bed, etc. can be effected.
With V, miles per 'hour as the main, or direct drive, a step up to four or five miles could conveniently he devised for the lighter work on the land, such as harrowing, harvesting etc. In the simplest form of tractor, a reverse will not be needed ; when fitted, it will naturally .be about 2 or 21 miles per hour.
I have still to make my oft-promised *reference to the caterpillar type of agrimotor. Strictly speaking, this should have been included with the dimension of wheel sizes. By leaving it till later, I consider that. I have avoided any chance of confusion. It is clear that the only way in which the " caterpillar" (I go in constant dread of offending Mr. Feeney, of Caterpillar Tractors, Ltd.) type of machine •differs from the wheeled one has reference to wheels, and that it should be considered in the same light as the wheels.
It is clear that,. from that standpoint, the chain track has all the advantages of an "outsize" wheel. Its bearing surface on the ground is so large as to be comparable with a wheel of several times that of the normal. It has not the weight of the extra large wheel, and makes no depression ; except in a minority of soils, it aloes not require to have spuds fitted. The two main losses of power which occur in connection with a wheeled machine are, therefore, obviated. Where a front steering wheel is not proviied, it can, by manipulation of its tracks, swing round in practically its own length, a characteristic only shared by two-wheeled, self-contained outfits like the Wyles and Moline. So far, the circumstances would seem to plead for its universal adoption.
The fly in the ointment is undoubtedly the wear and tear of the chain track, together with the undoubted fact that the advantage in respect of power loss which it has over the wheel is offset by the inefficiency of the chain itself. The problem of wear is being tackled, in several directions, by different makers. Mr. Martin, of Martins Cultivators, Ltd., is, after several years of experiment, now using a track which certainly appearS as though it would last. Mr. Burford showed me the parts of the track on his original demonstration machine, which has been in use for four months. The evidence of wear,. I must admit., is remarkably small. He claims a life of 500 acres for a pair of tracks, and hopes to be able to sell them at £25 a pair—which is equivalent to a shilling an acre. If his expectations are realized, the buyer of a Cleveland is on to a good thing. He is whether or no, in ray opinion ; but a guarantee of a shilling an acre for chain-track replacement should clinch it.
I had an experience only the other day with a machine of this type—one of the larger types nominally capable of pulling a four-furrow plough m most soils. It was at work on what would be described as a good rich loamy soil—sand and clay. It was a little soft, but not much. The tractor, doing its utmost, had to shed two of its ploughshares, and then proceeded with difficulty. The joints of the chain track were clogged with the sticky soil, which was not, by the way, difficult material to work, and the efficiency of the chain-track was reduced to a very low figure. the present effect of the grit and sand on its pins and joints is better left to the imagination. Ultimately, I am afraid, a more taugible result will accrue.
On points, it would therefore seem that the wheeled tractor scores. When performing, a machine like the Cleveland excites my admiration every tinac3 and I look forward to Mr. Burford's vindication of his statement as noted above. His machine has advantages, too, on grounds of simplicity.
Once the problem of wear and tear is solved, the chain track will have the ascendency. It all appears to come back, however, to the plain fact that the transmission gear of a machine like a tractor, which has continually to work in grit, soil, and sand, must be enclosed. At present the way out for the "caterpillar" would seem to be the provision of tracks for renewal purposes at low price and capable of easy
and rapid replacement. AGR1MOT.