72-74, Gray's Inn Road, London, W.C.
Maker of the Opperman electric vehicle.
1920 The design was revised and the automatic lubrication system was replaced by mechanical-pump oiling. The two-speed gear option was withdrawn.
1922 Only a three-speed model with a Sturmey-Archer gearbox survived for that year, and then the marque disappeared.
There was an earlier Corona, built circa 1901-1904, unrelated. Corona
AN interesting new machine which will be exhibited at Olympia is the Corona Junior, which has been but recently designed and is now being manufactured in large quantities by the Meteor Manufacturing Co., Ltd., of Tollington Park, London, N.
One of the principal features of this machine is that the number of parts employed is claimed to be less than on any other machine.
The 4 h.p. four-stroke engine, which has a bore and stroke of 72x110 mm., has its cylinder cast integral with the crank case, and has a detachable combustion head. This is constructed ot a special alloy which has a high conductivity, and permits the decarbonisation of the piston and cylinder head whilst the engine is in the frame. The crankshaft is a one-piece steel stamping and is offset from the centre line of the cylinder, which, the makers claim, reduces wear and side strain on the cylinder .walls.
Totally enclosed valves, fitted with adjustable tappets, are employed, and are operated directly from the cams machined integral with the timing wheel and magneto chain sprocket, thereby dispensing with the use of rocker arms, and self-aligning ball bearings are used for the main bearings. Automatic lubrication has been incorporated, a constant level of oil being maintained by means of a mechanical pump. A single-lever carburetter is provided, and a welded steel silencer of novel design, which can be rapidly dismantled by removing one bolt.
Knock-out spindles are fitted to both wheels, the rear one of which carries the totally enclosed internal expanding brake. A noteworthy feature of the Corona Junior is the method of springing the front wheel, the mechanism bemg enclosed.
Three models will be standardised, a light solo mount with fixed belt drive, a similar machine fitted with a two-speed countershaft gear box, and a third model, designed for sidecar work, which will be equipped with a three-speed gear and an enclosed clutch and kick-starter.
It is extremely illuminating to note the interest being taken in the single-cylinder; would-be prophets would have us believe that the end of the single-cylinder is in sight, but still it holds a high position as the most economical machine at a moderate price, in spite of the desirability of multi-cylinder engines for luxurious mounts.
The Motor Cycle November 20th, 1919.
Sources: Graces Guide, The Motor Cycle
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