• The Live Axle—Is It Dying?
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By " T he Inspector."
T IS, OF COURSE, quite a. number of years 1 since I took part, in a more or less insignificant way, in the A.C.G.B. and • I. 1000-miles trial. But I particularly recall the pleasure I achieved from being associated on several trips with one or two of the Wolssley car competitors. Few people in these days bother themselves to recall early trials, let alone their results and failures ; they are historical occurrences, it is true, and to have been directly associated with them is only of similar value to that of the proud announcement of a butcher who writes "Established 1846" on his facia board, or of the various ' original" makers of Bath buns who make strictly comparable claims as to the invention of that doubtful delicacy.
I, personally, have some little memory for historical happenings in things automobile, but I must confess I. remember far more of my trips on the medal-winning AVoiseleys than I do of those who were responsible for the organization. Those machines were, I remember,
early 10 h.p. and h.p. examples of the horizontalmotor product of the Adderley Park factory, and were chain driven from engine to gearbox, and from gearbox again to rear road wheels. Other designers than Herbert Austin, in those days, flirted with this form of drive, but Austin and Hans Renold between them produced a form of transmission which in those days left all its competitors, or nearly all, standing, in matters of reliability, of hill-climbing, and of horse-power at the road wheels. A lot of this was put down at the time to the horizontal motor, but I never subscribed to that view. The Wolseley horizontal engine, of which many thousands must have been installed (the first few British submarines had them as a matter of fact), was successful in spite of, and not because of, its attitude to things in general. The facility with which the Wolseley car of early days gained such easy laurels in hill-climbing competitions and consumption trials was due, in my opinion, to the fact that the efficiency of the whole chassis was so high so much of the power actually got throsgh to the tyres. And the reason, again, for that was the use of cross-shafts and chain drives, and nothing but straight spur wheels and no bevels. The efficiency-of the chain drive is a very high one. It is a matter for considerable speculation as to why Austin, who built up a great reputation with his bevel-less chassis in the early days, should now be the godfather of a commercial lorry model with more bevels in it than any other of which I know. I would wager, anyhow, that the earlier machine had by far the higher mechanical efficiency.
Bearing in mind the undoubted and ascertained effi ciency of a good chain drive in chassis design, I am led to wonder whether this is the underlying cause of the growing international consensus of opinion that, for warlike conditions at all events, the chain drive is preferable to the live axle far all but the lighter range of lorry models. For cars there appears to be no such tendency of preference which is understandable. Not long ago the French Government's mechanical transport authorities allowed their decision to be made known in favour of the chain as against the live axle for the heavy models. Then followed the American specification for Government chassis constructionl model of broad-minded direction, in winsh permission is given to adopt either the chain or the live-axle final drive. Over and beyond these two examples, it is no secret that our own M.T., A.S.C., has had far too much live-axle trouble for its comfort, nor, I believe., is it denied that the chain-driven Albion and some of the non-subsidy impressed machines of Other known types have won golden opinions for their final drives.
Not a few of these decisions are due, I am convinced, to the high average mechanical efficiency of the chaindriven chassis, and to their consequent good road performances -With equal or even smaller engines. But beyond that is the difficulty of ensuring immunity from fracture for back-axle sleeves and casings. A great many well-known designs are .subject to this and similar trouble under severe conditions. The forged hollow banjo-pattern backsaxle removes much of this trouble it is to be presumed, but even that type is not so free from trouble as is the solid-forged dead axle as used for chain drive. Torque tubes and their attachments in various forms cause a great deal of anxiety, and they, of course, are an accompanying and neces
i sary evil, n one form or another, of the live axle, and
are not required on the " dead " one.
Chains to be really efficient, should be properly encased and efficiently lubricated. Whether the military authorities are prepared to sacrifice rapidity of replacement and ease of inspection in favour of the provision of chain cases is yet to be seen. .They are both factors which, for Army employinent and for future use in the Colonies, and elsewhere where roads and loads are rough, are of great attraction. Highlystressed live-axle components are, I suspect, doomed to eclipse by the chain for 3-ton net-load chassis and :the bigger ones. For buses, and the smaller lorries and vans, and for touring cars • and their relations the live axle is a simpler problem. But that there are world-wide, indications that there is to be a reversion to chains for the heavier loads no one can deny. .