Isotta Fraschini Delta

Delta
Preserved Delta RC131
Type	V-12 piston engine
Manufacturer	Isotta Fraschini
First run	1927
Number built	c.3,300

The Delta was a 12-cylinder inverted-V aircraft engine built by Isotta Fraschini prior to and during World War II.

The Delta is a fairly rare example of a large air-cooled inline engine, which normally have cooling problems with the rearmost cylinders. It produced about 750 hp in common versions, although others were rated up to 900 hp. The Delta was not widely used, although it could be found on a number of production aircraft and some advanced prototypes.

The engine included a number of otherwise advanced features. For instance, the valves were powered by dual overhead cams driven by power shafts at the rear of the engine. Exhaust ports were arranged to exit toward the middle of the engine, one cylinder bank being the mirror of the other, allowing the piping to be ganged below the engine nacelle.

Data from

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Wikipedia