Radial Engine - Multi-row Radials

Multi-row Radials

Originally radial engines had one row of cylinders, but as engine sizes increased it became necessary to add extra rows. The first known radial-configuration engine to ever use a twin-row design was the 160 hp Gnôme "Double Lambda" rotary engine of 1912, designed as a 14-cylinder twin-row version of the firm's 80 hp Lambda single-row seven-cylinder rotary, with only the German Oberursel U.III clone of the Double Lambda reproducing the Gnome Double Lambda's twin-row design before the end of World War I. Most stationary radial engines did not exceed two rows, but the largest displacement mass produced aircraft radial engine, the R-4360, with cylinders in corncob configuration, was a 28-cylinder 4-row radial engine used in a number of large American aircraft in the post-World War II period. The Soviet Union built a limited number of 'Zvezda' engines with 56 cylinders but aircraft engines of this size, power and complexity were made obsolete by large turboprop engines which easily exceeded them in power without the weight or complexity. Large radials continued to be built for other uses though, as 112-cylinder Diesel boat engines with 16 rows of 7 cylinders each displacing 383 liters (23,931 in3) and producing 10,000 hp (7,500 kW) were used on fast attack craft, such as Osa class missile boats.