The total weight • of the machine when ready for
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work is 34 tons, and the overall .dimensions are: length 12 ft. 9 ins, and width 6 ft. 6 ins. The engine is designed to work on either paraffin or petrol, but petrol is only required for a period of five minutes after starting. Lubrication has been carefully attended to ; that to the engine bearings is by pump and troughs are provided under the connecting rods. Spring grease cups are fitted to all shaft journals. The tractor in the ordinary course will take four ploughs on stiff land, or will draw three 8 ft. binders and will drag harrows 12 ft. wide. The engine is fitted with a governor, and the belt pulley is there-. fore suitable for driving threshing and other farm machinery. As a road tractor it will pull loads up to 12 tons.
Amongst the light steam agricultural tractors which will take part in the Lincoln -Trials is the Mann. a well-known and very successful machine and one which is so simple that anyone who has had experience with ordinary steam tractors can handle without any difficulty.
The Mann will haul a four-furrow plough in strong land and will take loads up to six tons on the road. It will also drive from the flywheel a full size 4 ft. 6 ins, threshing machine with straw elevator, etc. The road wheels have a total width of 4 ft. 8 ins., and as the front ones track differently from those behind, the weight of the engine is well-distributed and no damage is therefore done to the land.
The boiler, which is constructed for a working pressure of 200 ha. per sq. in., is of the locomotive type, and can maintain a full head of steam during the heaviest ploughing.
The standard size boiler is suitable for burning coal or coke, but a larger firebox can be provided for burning wood when required.
The engine is of the compound type with side-byside high and low pressure cylinders, similar to those used on the well-known Mann steam wagons. A tank which carries sufficient water for half a day's ploughing without replenishing is provided. The engine is of the overhead type and is provided with a large flywheel as well as a governor and water lifter.
If required, the machine can •he obtained 'with a winding drum complete with steel swim rope. The tractor can carry two tons on the platform above the tank, and when the latter is loaded or ballasted it can be used as a road roller, owing to its wide wheels.
The Mann tractor is mounted on springs on both axles, and consequently comes under the Motor Car Act.
The steering is of the usual traction engine type consisting of a minima and worm wheel which drives a cross shaft on which the steering chain is wound. The weight of the tractor empty is 4-& tons, and it is very substantially built. The gearing is arranged to give three speeds, which are ample for all classes of work connected with the farm
Th:e Glasgow tractor is of the three-wheeled type in which all wheels are driven, and is arranged so that when in motion there is an equal distribution of weight upon all the wheels. It is substantially: built of good material, and there are many sound points in its design. It has no frame in the direct sense of the word. The crankcase takes the load at the front end, and the transmission casing at the rear.
The engine is four-cylindered, 44 in. bore by 5,1in. stroke, and is rated at 25 hh.p. It is intended that it shall be run on petrol, but it can be arranged to run on paraffin if required. The lubrication system is of the combined forced feed and splash type. To prevent over-tanning, a governor of the Pierce type controls the engine speed.
All the gearing is enclosed in a dustproof easing
and runs in an oil bath. It allows for two forward speeds of 24 and 5 m.p.h., and a reverse speed of 2t m.p.h. No differential gears are used, but a patented compensating ratchet device in the front wheel drives gives the re'quired elasticity for turning. The wheel running at the largest radius overruns on the, ratchet, leaving theother two, which describe similar arcs, to exert the power for turning; by this method none of the power is lost and the. outside wheel acts simply as an ordinary steering wheel.
Final drive is effected by bevel gears both to the front and back axles.
Steering is of the ordinary Ackerman type with the connecting rod behind the front axle.
A hand wheel is provided by which the front axle, which is centrally pivoted, can be tilted ; in this way the machine can be stabilized so that the engine unit is always in an upright position.
The radiator, which is situated at the front of the machine, is of the gilled tube type with a capacity of All the castings for the crankcase, eta, are of highgrade electro steel, while the shafts are of nickel steel, hardened, heat-treated and ground. The reduction gears themselves are of heat-treated nickel steel, and the ball bearings are Skefko self-aligning type.
The wheelbase is 6 ft. 3 ins., and the total width 5 ft.• the total length is 11 ft.
The driver's seat is at the extreme rear of the vehicle ; in fact, he sits over the drawbar, and thus has a clear, view of both the tractor and the plough, and, owing to the low height of the machine, he can also obtain a good view of the furrow in front A belt pulley is 'provided at the off-side of the machine and is centrally situated. It is capable of working the largest thresher and buncher. Dynamometer tests of drawbar pull have shown that the machine is capable of drawing a four-furrow plough requiring a pull of from 3,000 to 3,250 lb., at a speed of 3 m.p.h. It can also climb hills with gradients of 1 in 5, pulling a 4 ft. plough in medium soil.