The Rolls-Royce Griffon is a large, liquid-cooled V12 aero engine of approximately 37 litres displacement. It powered later Spitfires, Fairey Fireflies and the Avro Shackleton. Its long operational life extended Rolls-Royce piston-engine service well into the era of jet-powered military aircraft.[1][2][3]
Cylinder arrangement
The Griffon places twelve cylinders in two banks forming a V. Powerhouse's sectioned Griffon 74 illustrates a bore of six inches and a stroke of 6.6 inches, giving a swept volume of approximately 2,240 cubic inches. The museum records a compression ratio of 6:1 for this specimen. Liquid cooling and supercharging are central features of the engine's configuration.[2]
Supercharging
The preserved Griffon 74 has a two-stage, two-speed supercharger with intercooling. These components increase the pressure of the induction charge and control its temperature between compression stages. The museum rates this particular engine at 2,245 hp and associates it with the Fairey Firefly Mk.IV. Its sectioned construction makes the internal machinery visible, including equipment that would ordinarily be enclosed within the installed powerplant.[2]
Fighter and maritime roles
The Griffon replaced the Merlin in later developments of the Spitfire, while Firefly installations took it into naval aviation. The much larger Shackleton used four Griffons for maritime patrol, submarine-search and rescue duties. Yorkshire Air Museum describes the engines associated with its Shackleton WR963 as producing approximately 2,500 hp each, reflecting a different application and rating from the Firefly engine.[1][2][3]
Late service and preservation
The Griffon remained in frontline RAF service until 1991 through the Shackleton. An ex-Shackleton engine also powered the modified RB-51 Mustang racing aircraft, Red Baron. Preservation work on WR963 has included moving its engines separately from the dismantled airframe, with the aim of maintaining ground-running demonstrations. These activities preserve both an individual engine design and the large multi-engine installation in which it completed its military career.[3]