The Latest Air‐Cooled Engine: A 500‐h.p. Development of the Armstrong Siddeley Jaguar described and illustrated

MESSRS. ARMSTRONG SIDDELEY, of Coventry, have produced a new edition of the Jaguar engine, known as the Jaguar Major. While retaining the same overall diameter—46·75 in. (1·187 m.)—the power has been increased by enlarging the cylinder‐bore from 5 in. to 5.¼ in. (133·3 mm.), and the cubic capacity from 1,513 cu. in. (24·8 litres) to 1,667 cu. in. (27·31 litres). The new engine has a 3 to 2 reduction gear similar to that of the Jaguar, and is made with either a geared fan or supercharger. There are 14 cylinders arranged in two rows of 7, one master rod and six auxiliary rods being located on each throw of the 2‐throw crankshaft. The chief departure from previous practice, which is in general followed closely, is the incorporation of the rear cover with the engine bearer flange. Provision is made for the fitting of a hand, inertia or gas starter at the rear of the engine, and for dealing with two‐gun gear, dynamo drive, spare drive and auxiliary gear pump for the rotor drive.