Thornycroft.
Page 35
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pERHAPS the most striking exhibit on the Thornycroft stand is the 100 h.p. four-wheel drive Hathi (elephant) tractor, which is shown as a stripped chassis and is, beautifully polished and finished.
Pitted with a powerful six-cylinder engine and an eight-speed gearbox, this tractor constitutes a very useful unit for heavy haulage over rough ground. It has, of course, proved highly successful in the hands of the War Office, is capable of exerting a draw-bar pull of 9,000 lb., and will haul a 10-ton trailer up a gradient of 1 in 10 at 7 m.p.h. Furthermore, owing to the fact that the overhang at the front is reduced to a minimum, it can climb Steep banks where the normal vehicle will simply dig itself in.
In addition to the usual gears, the gearbox contains a transposing shaft giving alternative reduction ratios. The back and front axles are worm-driven and two powerful transmission brakes take effect upon all four wheels. A winding drum is fitted, which can be operated by the engine, and this embodies a very neat chain gear.
The gearbox is placed centrally and two propeller shafts convey the drive to worn-driven front and rear axles. That at the rear is of the orthodox type,-but, of course, the front axle embodies a special drive to allow of steering movements. At the end of each cross-shaft a bevel gear is located, meshing with a horizontal bevel wheel which is co-axial with the steering pivot. This, in turn, meshes with a crown gear secured to the frost wheel.
The whole of the drive is enclosed in two neat D-shaped housings turning one within the other when the front wheel is locked over for steeling purposes. The drop • arm of the steering box works transversely and is coupled to rod running across the chassis to the near-side steering arm.
The engine can be started by. placing a detachable handle on to either of two shafts, tease being placed to each side of the radiator and coupled to the crank shaft by a chain drive giving a 2 to 1 reduction. The engine is designed on modern lines, embodying six cylinders and overhead valves. A point of note is the up-to-date design of the induction pipe, which has extended ends and rightangle .bends.
Another striking exhibit is e 25 h.p. 30-cwt. Al freight chassis, also shown with polished finish. This well-known chassis is of particularly sound ; And straight-forward design and is, of course, eligible for the War Office subsidy. The specification includes a powerful four-cylinder side-valve engine and the exhibit is standard. in every respect but for the fact that the tyre pump shown fitted is an extra. An interesting detail is the gear-driven speedometer, now standardized and included in the price.
The 25 h.p. chassis also appears with a special bread-carrying boxvaix bpdy, and two further exhibits consist of the new long-wheelbase Al type shown as an 18-seater Dragon coach and as a tf0-seater single-deck omnibus for the Great Western Railway. The latter is attractively finished in chocolate and yellow colouring, and the seats ere ar ranged on each side of a central gang: way, There tire entrances at the front and rear. The wheelbase is 14 ft., and the chassis differs from the freight type in that the propeller shaft is divided into two parts with an intermediate universal joint. An interesting detail is the flexible disc mounting of the steady bearing which carries the rear end of the forward part of the propeller shaft. It shoeld be emphasized that the long wheelbase Al chassis is designed especially for passenger work, the springs, for example, being longer and more flexible than those of the freight chassis. The long wheelbase model is therefore not suitable for goods-carrying.
The exhibits are completed by the well-known J type chassis fitted with a 1,000 gallon, double compartment, petrol-carrying tank, the details of which comply with the L.C.C. regulations, this vehicle being supplied to a repeat order of Shell-Mex, Ltd., and the 50 h.p. Q-type chassis fitted with a 1,500-gallon tank. The latter has a special wheelbase of 17 ft., and is being supplied to the repeat order of the Anglo-American Oil Co., Ltd. Each of these vehicles is fitted with a weatherproof driver's cab, a fire screen and an exhaust system in which the outlet faces forwards. The smaller tank is divided into two compartments and the latter into three.
The engine employed is of the same type in each case, being the well-known Thornycroft four-cylinder with a bore and stroke of 4i ins. and 6 ins. respectively (121 mm. and 152 mm.), and each is fitted with a four-forward-speed gearbox, cone clutch and worm-driven' rear axle. Semi-elliptic springs are fitted fore and aft, and the chassis are
mounted on solid tyres. Lower gear. ratios are, of course, employed.
the case of the heavier vehicle, the speed, on top gear at 1,200 (engine) r.p.ra. is .13i m.p.h. for this model, as compared with 17i m.p.h. for the J type'.
John I. Thornycroft and Co., Ltd. Thornycroft House, Smith Square, S.W.