A dark clockwork comprising duty, ambition and hurt pride winds up Captain Scott and sets him on his path back to Antarctica.
Reginald Skelton tests the second snow tractor design before handing the plans on to the Wolseley Motor Company, which produced the three examples sent south.
From “Scientific American,” May 14, 1910, p. 396 cont. 407
The practical success achieved with the gasoline propelled motor sleighs on the Shackleton and Charcot polar expeditions has prompted Capt. Scott to include a vehicle of this type for his forthcoming dash to the south pole. This vehicle is, however, distinctly different from the motor sleighs hitherto used. In the two previous cases the front of the car was mounted on runners or skates, a chain and sprocket with spuds which gripped the snow and ice being fitted at the position occupied by the wheels in the ordinary motor car. In the new sleigh, however, what may be termed an adaptation of the pedrail or caterpillar system has been resorted to, which imparts a greater degree of efficiency to the vehicle, and enables it to surmount obstacles and to travel over rough ice with ease. In view of the conditions prevailing and the work it is intended to fulfill in the south polar regions, the engine is of a special type. It comprises four vertical cylinders, cast in pairs, and developing twelve brake horse-power.
The sleigh is fitted with a runner, upon which bear the rollers of the chain. The latter passing between this runner and the ground supports the whole vehicle and propels it as the wheels revolve. There are no brakes provided, as the big reduction ratio of the worm renders it completely irreversible, so that brakes are not necessary. Similarly, steering gear is dispensed with, as such is not requisite, for in any open area such as an ice field steering is not demanded. When it is required to deviate to the right or left, ropes attached to the front of the frame can perform this function. Turning sharp corners, under some circumstances is admittedly exceeding difficult, but when working in its designed sphere this difficulty will not be serious, as sharp turning can be usually avoided.
The sleigh has a substantial wooden frame. Underneath is fitted a large undershield extending end to end so as to present a perfectly smooth surface to the snow. When the sleigh is under way, a curious fact is observable. The chain, where it touches the ground, appears to stand still, while the sleigh slides over it. This is the motion that actually takes place, for the top of the chain travels forward at twice the speed of the sleigh. It will thus be seen that in reality the lower part of the chain in contact with the ground constitutes a surface over which the vehicle itself can move.
The driver has his position on a box behind the engine, which seat forms a receptacle for tools, spare parts and other accessories. That the vehicle has great climbing power has been conclusively proved, for it will ascend steep banks of earth and ride over serious obstacles easily and without any appreciable diminution of speed.
Although this sleigh can carry a party and full equipment, its actual function is to act as a tractor for the haulage of ordinary sledges, the trailing vehicles carrying the loads. Upon completion by the builders, the tractor was taken to Norway by Capt. Scott, and submitted to some exacting trials on snow-covered Lake Fefor and the tumbled country in its vicinity, where the conditions were somewhat analogous to those prevailing around the south pole. Heavily laden trailing sledges were hitched on to the tractor and numerous journeys were made among the Norwegian ice fields. The vehicle proved itself fully capable of withstanding rough usage, and Capt. Scott expressed his complete satisfaction with the results achieved.