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A BIT OF REALLY BAD GOING.

26th January 1926
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Page 20, 26th January 1926 — A BIT OF REALLY BAD GOING.
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A Demonstration of Half-track Machines on Snow and Ice.

L-1E-W. days more strenuous than Friday, January _11 15th, could have been chosen for the test of vehicles designed to give a high performance on terrain which. is not provided with roads. It was on this day that Roadless Traction, Ltd., in conjunction with Morris Commercial Cars, Ltd., organized a demonstration of vehicles equipped with Roadless chain-track units, andthe scene of the test was Hounslow Heath. During ' the demonstration a steady fall of snow took place, and the temperature was in the region of zero.

Normally, the part of the heath used for the test offers much resistance to the passage of vehicles, owing to the sharp gradients into and out of deep depressions in the ground, and the presence of blocks of stone necessitates a good steering lock on the part of any machine which is used in their vicinity. On the day In question the snow was, on the average, well over ankle deep ; in many places it was knee deep, and the multitude of puddles and water-holes was coated with Ice. As can be imagined, the snow and ice tended badly to pack underneath the tracks and thus to provide a slippery surface. That the vehicles performed satiSfac torily on the whole is distinctly creditable. Had the weather been better it would ii.ave been possible to tackle a big water-splash which exists on the heath, but, owing to the previous rain and snow falls, the depth had increased to 4 ft., which, of course, made the attempt out of the question. As a test of the watertight qualities of the bearings of the track, it would have been a matter of the greatest difficulty to discover more satisfactory conditions, as there was a constant bath of slush and ice flowing over the tracks the whole time the vehicles were in motion.

Three 1-ton Morris-Roadless vehicles were drawn up close to the Bath Road for the demonstration, in company with one Guy-Roatiless machine embodying certain new experimental features and an F.W.D.-Roadless with trailer.

As our readers will remember, the basis of the Morris vehicle is the familiar 1-ton chassis, which has an engine of 75 mm. by 102 mm., claimed to give 30 b.h.p. at normal speed. The chassis is of the long-wheelbase type, and provision is made for the use of tracks or wheels, as may be desired, by means of the provision of extra brackets on the chassis for carrying the springs Of the track unit or rear axle. An auxiliary gearbox is provided to cope with the low gear ratios demanded when the tracks are in use. Two of the vehicles used at the demonstration had oversize radiator header tanks ; the third, however, had a normal-type cooling system. Two of the Morris vehicles were loaded with metal weights and scrap, whilst the third machine was only partially loaded and was equipped with seats for passenger carrying. _ The largest vehicle of the group was an F.W.D., loaded with 3 tons of metal scrap and drawing a solidtyred trailer, also claimed to he weighted with 3 tons. The F.W.D. had, of course, the usual three-speed gearbox and, in addition, a booster gear, which gave a bottom gear ratio of approximately 120 to 1. Across the rear of the chassis was a winding drum somewhat similar to those which were provided on the F.W.D.s destined for the Danish army and the Soudan Government, described in our issue of December •20th. The F.W.D. had giant pneumatic tyres on the front wheels.

An interesting point in connection with the Roadless tracks is the method of excluding water and mud from the track pin joints; formerly stainless steel and cork were employed, but a superior system is now in use in which ordinary steel and Woodite are employed. The latter material is stated to be better in that it does not permit the ingress of grit as does cork. So far as can be judged by the degree of freedom in the tracks of all vehicles at the conclusion of the tests, the gritty ice and slush had not found their way into the bearings.

From the point of view of a passenger in one of the Morris-Roadless vehicles the degree of comfort given in cross-country running was noticeable: although the seats were provided merely with stuffed cushions ; there was no jolting, but the passengers were, of course, swayed somewhat, owing to the sharp contours of the ground traversed. The tracks were commendably silent, but there was a certain amount of hum from the gears when pulling on low ratios over rough surfaces. This is no serious objection, as these machines are intended for goods" transport rather than passenger work ; even in the latter ease no reasonable grounds for complaint could be offered, as a machine of this type would be used on terrain and in circumstances where a little noise would be of no real importance.

The first obstacle which was encountered by the vehicles was -a "mud-hole " having a fairly gradual descent, but an ascent on the opposite side of the order of 1 in 2. The depth of the slush and frozen mud at the bottom of the hole was something like 18 ins. All vehicles traversed this successfully at the first attempt, although there was certainly a little track slipping due to the ice packing underneath. The ground clearance provided seemed ample for the work, despite the sharp crest of the rise of 1 in 2. Steam issued from beneath all the vehicles when traversing the mud-hole, but this, of course, was caused by the snow and ice which splashed on to the hot exhaust pipes and silencers. No evidence was visible, however, of contact with the ground.

Various other holes and hills were tried, only one proving at first to be insurmountable, not because of lack of power, but rather to ice packing. The Guy machine climbed this rise once or twice, and also failed once or twice, owing to slip. For the same reason the Morris vehicles came to rest with their tracks spinning on the slippery surface, but subsequent attempts were successful when a little run was taken at the rise, which again was in the vicinity of 1 in 2.

Although the idler wheels of the track bogey are rubber tyred, and run easily on the undersides of the track plates, the Presence of streams of gritty mud does not ease their progress. To avoid this type of " lubrication " mudshields were fitted on the Morris vehicles above the track pivot between the drive wheel and the main idler wheel. The liquid mud was caught and thrown clear in a satisfactory manner. It would appear that a fitment of this type is essential on all track vehicles, Another useful device applied to the Guy machine was a snow scraper, consisting of a horimmtal bar across the rear of the vehicle, provided with teeth and set fairly close to the track, so that, to a large extent, ice packing was overcome.

The value of four-wheel drive in conjunction with tracks was strikingly demonstrated by the F.W.D. A hole slightly wider than the vehicle track had been prepared, the depth being 22 ins, approximately and the sides being vertical, not sloping; this point is important. Whilst the Morrises and Guy were " gamboling " in the hills and hummocks the P.W.D., without Its trailer, was deliberately driven into this hole, its tracks resting on the level ground, but its front wheels were right, down in the hole, well above the axle centreline; the towing hooks on the front end of the chassis and the drop arm of the steering were actually resting on the forward edge of the hole: In the case of an ordinary rear-driven vehicle the forward pressure exerted by the track drive would have served but to ram the front wheels all the harder against the forward edge of the hole. Not so in the case of the P.W.D., however, and the faith of the spectators in the vehicle's performance was shown by the fact that no one was willing to gamble on the chance of the vehicle not getting out. So soon as it was found that there were no "takers," the driver was told to proceed. The bottom gear and booster gear were engaged, and the front end of the P.W.D. hoisted itself vertically out of the hole and went straight ahead.

Later the P.W.D. was connected to its trailer, which had previously been standing idle .during the maineuvres of the smaller machines in order to give them better room to show their paces. The mud-hole first mentioned was taken easily, but, owing to the steepness of the incline, some of the metal ballast fell overboard. The vehicle then turned round and descended the 1 in 2 section, which it negotiated safely, despite the sliding of the enormous metal weights from one end of the trailer to the other.

All the vehicles performed in a-very creditable man. ner, and the surface of the test ground saw to it that the chassis and vehicle parts were properly tested, as the various inclines and holes were taken—not at rightangles every time, but often at an angle of 45 degrees, which involved much twisting so far as the vehicle frame was concerned ; the off-side front wheel would be halfway down into a hole when the near-side drive wheel of the track was on level ground.

The Morris machines rah steadily and well throughout, except, of course, for the track slip on the. ice, which was due to no fault of the vehicre.s themselves, but was a point Which was common to all the machines on that day. Despite the comparatively small engines —13.9 h.p. R.A.C. rating—they proved themselves capable of hauling 1-ton loads over 'surfaces _which would be out of the question to all-wheeled vehicles, and progress was as rapid as could be expected in the circumstances.

Tags

Organisations: Soudan Government, Danish army

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