THREE DAYS' WORK
If you've noticed an error in this article please click here to report it so we can fix it.
ATRACTOR of quite remarkable design and capabilities for road haulage as well as for arduous cross-country work of all kinds, is the Lath l KTL-type 10-ton model, made in France and marketed in Great Britain by Lath l Industrial Vehicles, Ltd., 11, Albert Embankment, London, S.E.11. This tractor is almost unique as a regular production model, for it drives and steers on all four wheels, has two ranges of gear ratios, also instantly lockable differential gears for both fore and aft pairs of wheels, and it can be equipped with a belt pulley, a land anchor, a most powerful winch gear and special pneumatic-tyred wheels with folding steel spuds, which give an extraordinary tractive grip on soft ground, and can he folded out of the way in a few minutes for running on roads.
The principal dimensions of the tractor are :—
Wheelbase, 7 It. 6 9-16 ins.; track ffront and rear), 4 ft. 11 ins.; overall length, 12 ft. 27/R ins.; overall width, 5 ft. 101/2 ins.; frame width, 2 ft. 63/4 ins.; frame height, 2 ft, 63,i ins.
Details of the design have frequently been given in this journal, but the main features will be briefly outlined afresh. The side-valve four-eylindered engine, single-plate clutch (enclosed) and gear box form a unit spring mounted at three points in the frame. The engine has three main journals of 52 mm, diameter and 83 mm., 83 mm. and 95 mm. length, the big-end bearings being of the same diameter and 50 ram. long. By means of marks on the fan pulley and timing case the magneto can easily be retimed.
The gearbox has two compartments, the forward one containing the gears for three forward and one reverse ratio, operated by a ball-change lever mounted on the cover plate. The rear compartment contains pinions providing a high and a low range of ratios, also controlled by a lever mounted on the gearbox cover. By moving this lever into a third position power is taken to an auxiliary shaft to operate a winch, pulley or other mechanism, for which the three forward and one reverse speeds are available.
Normally, the drive from the main shaft, which carries the transmission-brake drum and cardan couplings at front and rear ends, is carried to fore and aft differential cases bolted to frame cross-members; thence universally jointed shafts transmit the drive to all four wheels through internally toothed gears, which z_fford a final reduction of 4.93 to 1. Both differentials can be locked simultaneously by a. control lever from the • driver's seat. The steering on all four wheels gives a most valuable advantage in difficult manceuvres, allowing a turning circle of but 27 ft. diameter..
Positive lubrication by pump is provided in the gearbox, whilst the final-drive gears are enclosed in oil-tight casings. The arrangement of the folding wheel-adhesion spuds is well known and can be understood. from our illustrations. The design: of the tractor and its equipment expresses ingenuity throughout and has been proved out in long and extensive usage. In the latest model the exhaust lead is from the front end of the manifold. A Bosch magneto is now fitted, with Flick impulse starting device. The steeling track-rod joints are not now Springloaded and are thread-adjusted.
Our test comprised one day engaged in beet collection from Norfolk fields, one day engaged in bringing in felled trees to a Berkshire sawmills and one day spent in trunk-road haulage with a 10-ton load.
For beet haulage we employed an Eagle trailer built for pay-loads of the order of 8-10 tons, a vehicle rather too big for the job.
It had a wheelbase of 7 ft. 5 ins, and track (between twin tyres) of 6 ft. 1 in. and, with the tractor, made an outfit 34 ft. long. The body length and width were 14 ft. 3 ins. and 7 ft. 4 ins., the floor height 4 ft. 6 ins. This fine trailer weighed empty 4 tons 11: cwt. and had twin 38-in. by 7-in. pneumatic tyre § on all four wheels. "Under load, with earth caked between the tyres, each wheel. presents an area of about 1 ft. 6 ins. by 1" ft. 6 ins., making a total of 9 sq. ft., to the ground surface, which is a help against sinking when the ground is soft.
• Needless to say, in the fields from which beet had just been lifted there were times when, even in the lowest of the six gears, the tractor could not, by direct haulage, shift the trailer with its load of 4 tons 16 cwt. of unwashed beet. On such occasions the tractor would move off to firmer ground, if available, drop anchor and use its winch gear. With• this it made light work of any kind of extrication job ; no situation was found from which the tractor could not shift the load. An average speed of 24. m.p.h. was maintained over ploughed fields, and then, after a five-minute halt for folding back the wheel spuds,
15 m.p.h. was maintained by -road to the beet factory.
For timber haulage we employed a Cranes extensible trailer of the kind described on page 468 of our issue dated May 12th. This had eight 40-in. by 8-in, pneumatic tyres, and the wheelbase could be adjusted, in 2-ft. stages, between 7 ft. 4 ins. and 19 ft. 4 ins., the track (between dual tyres) being 5 ft. 11 ins. The wheels had four 19-in. brake drums.
The work, completed between n a.m and 5 p.m., is summarized as fol. lows :— First journey.—Nine miles unladen, four miles laden (about 300 yds. on salt ground). Load, one elm butt of 184 cubic ft,.
Second journey—Four miles unladen, four miles laden (about 400 yds. on soft. ground). Load, one elm trunk ol 220 cubic ft.; length, 15 it.; maximum girth, 19 IL 6 ins.; minimum girth, 14 It.
Third journey.—Five miles unladen, ten miles laden. Load, six oak trees, totalling 190 cubic ft., gathered by the tractor from awkward locations in the forest up to 200 yds. from trailer.
• Totals.—Mileage unladen 18, mileage laden 18,_. timber brought in 594 cubic IL; three loadings, three unloadings; petrol consumed, 7 gallons.
Forestry and sawmill men will recognize in this summary the record of a fine day's work. The second elm trunk to be fetched was about 250 years old and had been lying more than a year. It would have been an impossible task for a horse team to shift, and solid-tyred steam tractors if brought to it, would have had serious trouble in the soft ground, apart from making very slow progress when they did get on the hard road. The Lath l made light work of it, hauling its trailer 200 yds. across country to the tree trunk, loading it and getting it " out " on the road within 35 minutes. The trailer was parked 12 ft. from the trunk; parallel to it, and the wheelbase was shortened to 9 ft, 4 ins. Two larch skids 2 ft. in girth were lowered, a chain loop passed under the trunk and coupled to the winch cable of the tractor, and with gentle use of the winch clutch the strain was taken, the trunk sliding up the skids on to the trailer bolsters.
On the return to the road the winch was used for one or two awkward extrications, but in the main direct haulage of the laden trailer was possible. Incidentally, when traversing park land the D20
winch may be used to obviate the slight marks of. the tractor spuds in the turf, but in practice these'. are nearly rolled out by. the following trailer tyres.
A valuable feature in timber work is that, should it be necessary to hold on one line while hauling in another, the first line may be held by declutching the winch and holding it with the brake, the second line being then wound in on the bollard. Again, to supplement the already useful range of gears, block tackle can be interposed, affording ratios capable of tackling practically any task.
On our third journey (details above) we had to leave the trailer on the road, penetrating the undergrowth with the tractor to locate and collect felled tree trunks. These averaged about 30 cubic ft. and were up to 20 ft. in length. They were hauled behind the tractor at speeds up to 10 m.p.h. and loaded two at a time. When the ground was very slippery the differentials could be locked in a second, so that the tractor cord go almost anywhere that horses cool work and with greater speed.
Considering that a team of up to six horses may be needed to get out a trunki of 140 cubic ft., the situation may be summarized by saying the Latil outfit. with two men, will pull out half as much timber again as six horses with four men and, on the class of work we were engaged on, can make two or three journeys to the sawmill instead of one in the day. The efficiency is more than doubled.
Our road test was made with an old trailer having solid tyres and rear-wheeU brakes. The weights, brake details etc., are given in the accompanying tablet, braking and acceleration curves also being reproduced.
Acceleration is not of first importance with an outfit of this kind, and the readings obtained are satisfactory. The brake equipment can be specified to the purchaser's needs, and our trailer was not well equipped considering the modern types of brake gear that are available.
The tractor brakes are remarkably powerful; the transmission (footapplied) brake alone would hold the 151 tons stationary on a gradient of 1 in 9. 'The accompanying braking graph shows the performance when foot brake and trailer brake together or foot brake and tractor hand brake together were applied, the results being identical. With modern four-wheel trailer brakes the former readings would have been better, for the Neste trailer-brake actuating mechanism works well and -gives an excellent leverage. It was found impracticable in the four or five aeeonds available to apply all three brakes, for the two hand-brake levers were on opposite sides of the driver. It is well understood that this class of outfit can be satisfactorily equipped with a power brake which will give superior results.
The • steepest hill tackled was West Hill, Highgate, in North London, a long climb with a maximum gradient of at least 1 in 9. Low second gear was used for the first part of the ascent and low first gear for the severe section, the time taken being 10 minutes and the speed about 3 m.p.h. A start from rest on the 1-in-9 gradient was easily effected. The water temperature in the radiator-head tank after the climb was only 175 degrees F.
For fuel consumption we filled the tank to the orifice neck when standing at a marked place on the road and refilled at the same spot after a journey of 36.6 miles. The speed averaged 10.46 m.p.h. and fuel consumption was at the
rate of 5,74 m.p.g. The speed was slightly affected, because, having an old trailer, we could not risk descending slight .tradients with the brake off.
The Solex 35 MOHDL-type horizontal carburetter was dismantled and found to have a setting of :—Choke, 26; main jet, 135; pilot jet, 60. This was not altered throughout the day's tests on the road.
A point which demands mention is the lightness and ease of the gear-change, steering and brake controls ; on road or country work these definitely do not fatigue the driver; in fact, they are practically as easy as on a big private car.
In this article we have but briefly recorded the work done in the course of our three-day test. We did not include ploughing or mole-draining. The KTL tractor is known to be capable of ploughing n to I acre per hour to a depth of 8 ins. to 9 ins., using a threefurrow or four-furrow plough, *word ing to the nature of the land. The machine is also extremely powerful for mole-draining work. In fact, with winch and land anchor, it is quite one of the most versatile types of powerdriven farm appliance that an agriculturist MI possess.