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 1921 Calcott light car.
| Identifier | ExFiles\Box 21\3\ Scan038 | |
| Date | 23th October 1920 | |
| X.3205 THE AUTOCAR, October 23rd, 1920. 707 THE 1921 CALCOTT. Detail Improvements the only Alterations in an 11.9 h.p. Light Car of Proved Popularity. SINCE its inception, the Calcott light car has always been popular, and will be little changed for 1921. Improvements have been effected, but only in details of construction. A four-cylinder monobloc engine, with valves arranged in line on the near side, is carried in the frame by four bearer arms. With a bore and stroke of 69 x 110 mm., the engine is rated at 11.9 h.p. A Zenith carburetter is attached to the off side of the cylinder casting, and an induction passage running between the second and third cylinders conducts the mixture to the inlet valves, while a detachable exhaust manifold on the near side conducts the burnt gases to the silencer, the exhaust system being commendably free of sharp bends. A cast aluminium plate covers in the valve stems and adjustable tappets, and is held by a single large thumbscrew. Accessibility Well Studied. Made from a solid-steel forging, the crankshaft is provided with three main bearings of large diameter, lined with white metal, while the camshaft is carried on ball bearings. The camshaft and the magneto driving spindle, which also is carried on ball bearings on the front near arm of the crank case, are driven by a silent chain, and a second silent chain is employed for the drive to the Lucas dynamotor, which is compactly built in to a circular extension of the distribution gear casing on the off side. The magneto is driven through a flexible leather coupling and two discs, one of which is slotted, thus affording a simple means of timing adjustment. Lubrication is by a gear type oil pump in the sump driven by a vertical shaft and skew gearing from the camshaft, and this pump supplies oil to the main bearings and to troughs. A large oil filler is conveniently situated on the rear engine bearer arm on the near side. Particular attention has been paid to the accessibility of the various engine components, and the carburetter and dynamotor on the off side are both easy to get at, while on the near side the magneto, oil filler, and valves are also easy of access. Cooling is by thermosyphonic action through a large radiator aided by an efficient three-bladed fan driven from a pulley on an extension of the magneto driving spindle. The Transmission System. From the engine a large fabric-lined cone clutch transmits the drive to the three-speed and reverse gear box, and in the new model a Hardy fabric universal joint replaces the sliding flexible joint which was formerly fitted between the clutch and gear box. The gear box is held on a simple sub-frame by three bolts passing through feet cast on the centre portion of the box. The box is split horizontally on the gear-shaft centre lines, special precautions being taken to render the joint oil-tight; by this construction it is possible to replace a worn gear wheel without disturbing the alignment of the gear box. Short splined shafts are carried on ball bearings. SPECIFICATION. 11.9 h.p., four cylinders, 69 x 110 mm. (1,644 c.c.) Treasury rating, 11.9 h.p. Three-bearing crankshaft. Magneto ignition. Fabric-lined cone clutch. Separate gear box, three speeds and reverse. Spiral bevel-driven full floating rear axle. Semi-elliptic springs, front and rear. 710 x 90 mm. tyres, on detachable steel wheels. Wheelbase, 8ft. 6in. Track, 3ft. 9in. Lucas dynamotor lighting and starting unit. A large oil filler is conveniently arranged on the rear engine bearer arm, the magneto and valve tappets are readily accessible, and the high-tension cables are carried in a metal clip. D25 | ||