Engineering Wonders of the World
Volume III

34 ENGINEERING WONDERS OF THE WORLD. no aluminium is used, and most of the parts are of nickel steel forged by hand. The stationary and hollow crank-shaft is attached rigidly to the frame of the flying machine, the cylinders and crank-case to the propeller itself—a position which gives the most efficient cooling—or to the propeller shaft. If circumstances demand, th© engine can be mounted with its axis vertical, to drive the propeller shaft through bevel gearing. All seven connecting rods work on a single crank. One of the seven, the “ master,” carries a double-disc big-end, pierced with six pairs of holes to accommodate the six pins for the rods (see Fig. 6). The big-end itself is separated from the crank by ball bearings. The 50 horse-power engine, with cylinders of 120 mm. stroke and 110 mm. bore, weighs but 160 lbs., or but little more than 3 lbs. to the horse-power. Fig. 7.—THE “ BAYARD-CLEMENT ” 55 HORSE-POWER SEVEN-CYLINDER ENGINE. WEIGHT, 155 LBS. The cylinders are stationary, but no fly-wheel is needed. (Photo, Topical.) The explosive mixture is drawn by the movements of the pistons through the crank- shaft into the crank-case, whence it finds its way into the cylinders through automatic inlet valves situated in the piston heads. These valves are counterbalanced, so as not to be affected by the centrifugal force of rota- tion ; the same remark applies to ’the exhaust valves on the cylinder heads, operated by rods and rocking levers from cams rotated by epicyclic gearing at the end of the crank- case. The magneto and a pump for cir- culating lubricating oil are mounted on the shaft, and do not revolve with the engine. The Bayard Clement Engine. The Bayard-Clément seven-cylinder engine (Fig. 7) differs from the “ Gnome ” in that the cylinders are stationary and the crank revolves. The exhaust and inlet valves of each cylinder, situated on the head, are operated by a single rocking lever. A small pump, mounted in the crank-case on the crank-shaft, drives water through jackets sur- rounding the cylinders. The carburettor, out- side the case, is connected by a single pipe to a chamber inside the case adjacent to the pump. From this chamber pipes run through the walls of the case to the seven inlet valves.