Engineering Wonders of the World
Volume III

AERONAUTICAL ENGINES. 37 The English-built Jap engine has a bore of 85 mm. and a stroke of 95 mm., and develops Fig. 10.—“ FIAT ” EIGHT-CYLINDER 40 HORSE- POWER AIR-COOLED ENGINE. WEIGHT, 135 LBS. {Photo, Topical.') 30-35 horse-power at 1,000 revolutions per minute, and weighs about 5| lbs. to the horse- Fig. 11. — EIGHT - CYLINDER “ PIPE ” AIR-COOLED ENGINE. 70 HORSE - POWER WEIGHT, 280 LBS. The cylinders are enclosed in jackets, through which air is forced by a fan. {Photo, Topical.) power. The 70 horse-power Pipe engine (Fig. 11) weighs 280 lbs., and has cylinders of 100 mm. bore and 100 mm. stroke. It works at very high speeds—up to 2,000 revolutions per minute. The cylinders, furnished with longitudinal cooling ribs, are covered by light aluminium jackets, through which air is forced by a centrifugal pump mounted on the crank-shaft. Another interesting feature is that the valves of each cylinder are con- centric, and operated by pairs of overhead rockers, one of which is forked so as to allow the point of the other to move through it. The Gobron engine (Fig. 12) is very distinc- tive both externally and internally. The eight cylinders are arranged in four pairs to form a cross. Tn each cylinder are two pistons working in opposite The Gobron. directions. When an explosion occurs the pis- tons are forced apart, one moving towards, the other away from, the crank-shaft. The eight inner pistons have the usual connecting rods to the crank; the outer pistons of a pair of cylinders are connected to a common cross- beam from which long connecting rods run Fig. 12.—EIGHT-CYLINDER CROSS-SHAPED “ GOBRON ” ENGINE. The 80 horse-power type weighs 440 lbs. {Photo, Topical.) outside the cylinders to separate cranks, set in line at an angle of 180° to th© central crank.