It is Rotec Engineering Ltd., a manufacturer of two radial engines that are used by Homebuilders.

“Rotec R-2800”

-The Rotec R-2800, with 7 cylinders, gives 110 HP. Despite being of a current design, it is conservative.

-The figure 2800 refers to the cc of total displacement (172 cu. in.) and the 110 HP is obtained at 3,700 crankshaft rpm, therefore, it has reduction gear with a 3:2 ratio. It uses a Bing carburetor.

“Rotec R-3600”

-Another Rotec is the 150 HP nine-cylinder, which we can see in the above picture. It is apparently an enlarged version of the previous one.