The accompanying diagram illustrates a later Wolseley model, end elevation, the eight-cylindered 120 horse-power Vee type aero engine of the early war period. With this engine, each crank pin has two connecting rods bearing on it, these being placed side by side and connected to the pistons of opposite cylinders, and the two cylinders of the pair are staggered by an amount equal to the width of the connecting rod-bearing, to afford accommodation for the rods. The crankshaft was a nickel chrome steel forging, machined hollow, with four crank pins set at 180 degrees to each other, and carried in three bearings lined with anti-friction metal. The connecting rods were made of tubular nickel chrome steel, and the pistons of drawn steel, each being fitted with four piston rings. Of these the two rings nearest to the piston head were of the ordinary cast-iron type, while the others were of phosphor bronze, so arranged as to take the side thrust of the piston. The cylinders were of steel, arranged in two groups or rows of four, the angular distance between them being 90 degrees. In the space above the crankshaft, between the cylinder rows, was placed the valve-operating mechanism, together with the carburettor and ignition system, thus rendering this a very compact and accessible engine. The combustion heads of the cylinders were made of cast-iron, screwed into the steel cylinder barrels; the water-jacket was of spun aluminium, with one end fitting over the combustion head and the other free to slide on the cylinder; the water-joint at the lower end was made tight by a Dermatine ring carried between small flanges formed on the cylinder barrel. Overhead valves were adopted, and in order to make these as large as possible the combustion chamber was made slightly larger in diameter than the cylinder, and the valves set at an angle. Dual ignition was fitted in each cylinder, coil and accumulator being used for starting and as a reserve in case of failure of the high-tension magneto system fitted for normal running. There was a double set of lubricating pumps, ensuring continuity of the oil supply to all the bearings of the engine. [Illustration: End View of Wolseley 120 horse-power Vee-type Engine.] The feature most noteworthy in connection with the running of this type of engine was its flexibility; the normal output of power was obtained with 1,150 revolutions per minute of the crankshaft, but, by accelerating up to 1,400 revolutions, a maximum of 147 brake horse-power could be obtained. The weight was about 5 lbs. per horse-power, the cylinder dimensions being 5 inches bore by 7 inches stroke. Economy in running was obtained, the fuel consumption being 0·58 pint per brake horse-power per hour at full load, with an expenditure of about 0·075 pint lubricating oil per brake horse-power per hour.