From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Article from 'The Autocar' magazine detailing the benefits of supercharging and the new 10-40 HP Mercédès chassis.
| Identifier | ExFiles\Box 22\5\ Scan113 | |
| Date | 13th April 1923 | |
| Reprinted from The Autocar April 13th, 1923 THE BENEFITS OF SUPER-CHARGING. First Detailed Description of the Hitherto Secret Mercédès Super-charger. A Test of the New 10-40 h.p. Chassis. FOR many years the possibility of employing forced induction has been the subject of continuous experiment at home and abroad. It has been known that the German Mercédès engineers, who are admittedly amongst the most brilliant in the automobile industry, have devoted years to the perfection of a system of super-charging, but details hitherto have been lacking and, indeed, suppressed. During the war, of course, several aeroplane engines of various nationalities were designed to operate on some system of forced induction, or, as it is generally termed, super-charging, and that the principle is in no way new is further proved by the fact that ten years of experiment have gone to the production of the Mercédès super-charger in its present form as standardised on the 10-40 h.p. touring chassis. Principle of Super-charging. Briefly, the object of a super-charger is completely to fill the cylinders with explosive mixture at high crankshaft speeds; for on a normal engine, where the gases are aspired into the cylinders by the descent of the pistons therein, it is a difficult matter to ensure that the cylinders shall be completely filled at such speeds. It is largely owing to this problem that high efficiency engines, both for automobile and for aviation work, have lately developed with a multiplicity of overhead valves and complex carburation systems employing several carburettors. The super-charger is another method of attaining the desired result, since a blower is utilised to force air through the carburettor and so to deliver mixture under pressure to the cylinders. Mercédès racing cars, fitted with super-chargers, took part in the Targa Florio race in Sicily last year, and now, as the result of many years' experimental work, the 10-40 h.p. touring car has made its appearance as a standard production. The first of these chassis quite recently arrived in this country, and we seized the opportunity last week of examining and testing this latest example of advanced automobile design in order to keep readers au fait with German developments. Engine Details. Before dealing with the performance of the car, it will be well to summarise the features of this new chassis, so that the results may be judged in their proper perspective. The engine is on modern lines, but the use is continued of a cylinder block built up from steel forgings welded together. The bore and stroke are 80x130 mm. (2,614 c.c.), so that the R.A.C. rating is but 15.8 h.p., while the engine is comparatively small, being well under three litres. Two overhead valves per cylinder are employed, actuated by an overhead camshaft, driven through bevel gears by means of a vertical shaft at the rear of the engine. Also actuated from the bevel drive of the overhead camshaft is a cross-shaft, which drives the water pump on the near side and the magneto on the... DATA FOR THE DRIVER. 10-40 h.p., four cylinders, 80x130 mm. (2,614 c.c.). R.A.C. rating, 15.8 h.p. Tax, £16. Overhead valves, super-charger-forced induction. Magneto ignition. Tested weight of complete car, less passengers, 1 ton 5 cwt. 1 qr. Weight per c.c., 1.1 lb. Gear ratios: 4, 6, 9.8, and 16.5 to 1. Semi-elliptic front and cantilever rear springs. 820x120 mm. tyres on detachable wire wheels. Wheelbase, 10ft. 2in. Track, 4ft. 8in. Fuel consumption, 30 m.p.g. Tank capacity, 18 gallons. Price, chassis, [blank]. Image Captions: Exhaust side of the 10-40 h.p. engine. The super-charger is mounted on the front of the crank case, and the air intake and delivery pipes are shown. Steel forgings are used for the cylinders, and the overhead camshaft is driven by a vertical shaft at the rear of the engine. Diagrammatic plan view of the induction system. From the hot and cold air inlets on the near side the large suction pipe is taken to the blower, and the delivery pipe to the carburetter is on the off side. The normal air inlet pipe runs between the cylinders direct to the carburetter, and a butterfly valve is incorporated in it. Diagram Labels: SUPER CHARGER, INTAKE to SUPER CHARGER, MUFF, EXHAUST MANIFOLD, FUEL SUPPLY FROM TANK, FUEL SUPPLY, FUEL SUPPLY TO CARBURETTER, AIR VALVE, NORMAL AIR SUPPLY, AIR TEMPERATURE REGULATOR, CARBURETTER, FORCED INDUCTION PIPE. Handwritten text: 4409 34 x 37 | ||