Engineering Features of the Olympia Motor Show
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ALTHOUGH the number of makes of car on view is smaller than in previous years, the Olympia Motor Show, which opened last Thursday and does not close -until Saturday evening next, contains a great deal to interest the technically minded. Whilst it is true that the designers of cars and commercial vehicles have, for some years, been following rather diverging paths, the vehicles still have sufficient points of similarity to make an exhibition of one class interesting to those concerned with the other.
Two of the new cars on view—the Wolseley Hornet and the 15-18 h.p. Lanchester—show distinct signs of following commercial-vehicle practice in economizing chassis space, as in each case the radiator is mounted some distance ahead of the usual position adopted for motorcar work. thing to this plan it has been found possible to shift the engine farther forward, so increasing the body space, while retaining a moderate wheelbase.
The new Lanehester, incidentally, embodies a number of interesting features, including the familiar Daimler transmission system and a Lockheed hydraulic braking layout, in which the master cylinder is operated through a Dewandre servo motor. This combination works well in practice, and is used in a somewhat different form on the new Stutz.
Practically every car at the Show embodies some form of special gearbox, the most popular being a four-speed type with a silent-third ratio obtained by means of constant-mesh helical gears. There is just one example of a direct drive on third and an over-geared top, the Mercedes-Benz.
As an aid to gear-changing, Cadillac, Buick, Auburn and Vauxhall cars now use the synchro-mesh system, in which the parts to be engaged are automatically brought to the same speed by spring-loaded cone clutches.
The Wilson self-changing gearbox, pioneered by Armstrong Siddeley and now also used by Daimler and Lanchester, has found a new adherent in the famous Italian-built IsottaFraschini. Another interesting chassis is the new sixcylinder Lagonda incorporating a gearbox, made under Maybach licence, in which the special dogs used to engage the constant-mesh gears are pre-selected by levers on the steering column, and are operated, by engine suction when the accelerator pedal is momentarily released. A reduction gear can also be brought into action to lower the fourforward-speed ratios when operating in hilly country. Free wheels are either fitted, or are available as optional extras, on nearly every American and Canadian car shown E44 at Olympia. One British car has provision made for fitting a free wheel (the De Lavaud), this being the Talbot.
An examination of power units at Olympia makes it obvious that every effort is being made to prevent the engine from being either felt or heard by the occupants of the car. Stiffer crankcases and crankshafts, vibration dampers on sixcylinder models and mountings having rubber blocks or springs are all being used to check vibrations. An outstanding example is the new four-cylinder ChTyslet Plymouth, in which the engine is allowed to rock (when subjected to torque reaction) on an inclined axis joining the high support at the front to a low support behind the gear box. Both anchorages are made flexible with rubber, undue movement is checked by a leaf spring and the axis passes approximately through the centre of gravity.
The V-type engine is enjoying quite a votue for expensive . and powerful cars, as witness the Daimler Double Sixes and three new models—a Cadillac and a Hispano-Suiza, each with 12 cylinders, and a 16-cylinder narrow-angle Marmon. This Marmon engine is a beautiful job, with the cylinder blocks and crankcase formed in a single casting of aluminium alloy. The same material is used for the cylinder heads and the sump. The capacity is 9 litres and the output is stated to be 200 b,h.p. It is interesting to note that this engine, in common with the Hispano-Suiza, the Star and the Sunbeam, has separate cylinder liners.
Conventional springing systems still hold the field, but some interesting alternatives are on view. Mercedes-Benz, Peugeot; Lancia and Rover all show models in which either two or all four wheels are sprung individually without axles.
Another interesting car is the new Packard, in which the check valves of the four hydraulic shock absorbers are connected to a control on the dash.
In conclusion, it may be of interest to mention that there is only one front-wheel-drive car at the show, and that there are now two examples of a rear-engined layout for a lowpriced car—the Trojan and the new air-cooled Rover Scarab.
A complete report of the Show appears in the current number of our associated journal, The Motor?.