NEW F.W.D.-ROADLESS TRACTION VEHICLES.
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Details of Two Interesting Cross-country Units Which Have Been Built for the Danish Army and the Sudanese Government Respectively.
IT HAS been proved that the vehicle .driving on all four wheels is peculiarly adapted to the requirements of crosscountry transport, particularly when equipped with a chaintrack driving device, such as the successful type made by Roadless Traction, Ltd. This fact is being recognized by other countries than our own, and it is extremely interesting to .learn that the Four Wheel Drive Lorry Co., Ltd., Buckingham Avenue, Traeing Estate, Slough, recently supplied two F.W.D. vehicles equipped with chain-tract driving units and, in one case, also with a specially designed winch gear, having
an automatic coiling device, the latter being a long-wheelbase machine for.the Sudanese Government, whilst that for the Danish Army is a short-wheelbase model, but especially equipped with a larger engine than normal and a radiator giving 66 per cent, more cooling surface than that afforded by the largest type previously employed by the company."
Dealing first with: the vehicle for the Sudan, this affords a body space of 16 ft. It has a standard power unit of 4i ins. bore, and the radiator is provided with an extra large top tank. We have already described the F.W.D, booster gear which is employed between the clutch and gearbox.In this chassis the gear is not used as a booster, but as a reducer, which .affords au extra low gear, the final-drive ratio being further decreased by altering the silent chain reduction in the main gearbox. On top gear the total reduction is 14-1, and on bottom gear 115-1, and to take this drive what may be described as a super 6-ton rear-axle is fitted, as nearly all the drive come on to the tracks which, necessarily, offer the greater resistance.
At the back of the chassis is provided a winch carrying 250 ft. of stout steel cable and. having nigger heads or capstans at its ends. The drive for this :winch is taken from the. top of the main gearbox through a shaft with an intermediate bearing and couplings, and -thence vinti bevel .gears to a cross-shaft; from which it is conveyed through a spur reduction gear to the winch drum, the reduction .gear being en-. closed. • On the winch itself is carried an archimedian-spiral type of paying-out gear to ensure even wihding of the cable... This gear is driven through the medium of roller chains from a sprocket mounted on the carrel of the winch.
Just below the intermediate bearing on she winch drive the frame side members have been drilled to take standard spring brackets, and a special set of parts was supplied with the chassis, ,so that, at any time, it may be converted from a Roadless Traction vehicle to a standard lorry having fourwheel drive an4 equipped with 40-in. by 8-in. pneumatic tyres throughout ; normally, 40-in. by 8-in. tyres are used on the front wheel and as the brake equipment was designed for 34-in. .tyres, different crown wheels and pinions are employed in the front and back axles.
Fuel is supplied from a 40-gallon petrol tank, carried behind the 'driver's seat, which feeds a Zenith carburetter provided with a Stromberg sand filter. Other fittings on this vehicle include a B.L.I.C. magneto, a special type of Lacy-Hulbert tyre pump and acetylene headlamps. The body is of the fixed-side type, the sides being 2 ft. ins. high and having splayed-out top boards. The vehicle for the Danish Army embodies a larger engine having cylinuers of 5*-in. bore. The reducing gear employed in this vehicle is similar to that already described, but standard ratios are employed in the main gearbox, so that the 'eduction on top gear is 10-1 and on bottom gear 91-1. The chassis is shorter and carries a body 11 ft. long.
This vehicle also is equipped with a winding drum at the rear, but the nigger beads are absent. In this instance, a C-A.V, electric lighting and starting outfit is provided.
With this type of machine, having frout-wheel drive in addition to the track drive at the back, the tractive effort is remarkable, and on some tests carried out with the Watson 'merely forced right into the bank, probably pushing the front axle back, ashes happened in a number of, cases with drive at the rear only, the pressure from the rear merely assists the front wheels in. climbing Over the obstacle.
To show what can be done with a chain-track vehicle of this type, we publish a number of illustrations showing an example passing through a deep hole partly filled with water and made in ground consisting of slippery clay. Although this vehicle is shown performing the task while empty, actually the same hole has been. traversed with a ll-ton load, and on another occasion h trailer weighing 7 tons gross was pulled through it.