Editing Radial engine (section)

===Model radial engines===
A number of multi-cylinder 4-stroke [[model engine]]s have been commercially available in a radial configuration, beginning with the Japanese [[O.S. Max]] firm's FR5-300 five-cylinder, 3.0 cu.in. (50&nbsp;cm<sup>3</sup>) displacement "Sirius" radial in 1986. The American "Technopower" firm had made smaller-displacement five- and seven-cylinder model radial engines as early as 1976, but the OS firm's engine was the first mass-produced radial engine design in [[Flying model aircraft|aeromodelling]] history.  The rival Saito Seisakusho firm in Japan has since produced a similarly sized five-cylinder radial four-stroke model engine of their own as a direct rival to the OS design, with Saito also creating a series of three-cylinder methanol and gasoline-fueled model radial engines ranging from 0.90 cu.in. (15&nbsp;cm<sup>3</sup>) to 4.50 cu.in. (75&nbsp;cm<sup>3</sup>) in displacement, also all now available in spark-ignition format up to 84&nbsp;cm<sup>3</sup> displacement for use with gasoline.<ref>[http://www.saito-mfg.com/e-book/_SWF_Window.html Saito Seisakusho Worldwide E-book catalog, pages 9, 17 & 18]</ref> The German Seidel firm formerly made both seven- and nine-cylinder "large" (starting at 35&nbsp;cm<sup>3</sup> displacement) radio control model radial engines, mostly for glow plug ignition, with an experimental fourteen-cylinder twin-row radial being tried out - the American Evolution firm now sells the Seidel-designed radials, with their manufacturing being done in India.{{Citation needed|date=October 2014}}