Development was stopped temporarily to concentrate efforts on the smaller Merlin and the 24-cylinder Vulture; the engine did not go into production until the early 1940s.

Griffon engines remain in Royal Air Force service today with the Battle of Britain Memorial Flight.

This engine, R11,[1] which was never flown, was used for "Moderately Supercharged Buzzard development" (which was not proceeded with until much later), and bore no direct relationship to the volume-produced Griffon of the 1940s.

[nb 1] The design process was relatively smooth compared with that of the Merlin, and the first of three prototype Griffon Is first ran in the Experimental Department on 30 November 1939.

[2] One significant difference was the incorporation of the camshaft and magneto drives into the propeller reduction gears at the front of the engine, rather than using a separate system of gears driven from the back end of the crankshaft; this allowed the overall length of the engine to be reduced as well as making the drive train more reliable and efficient.

[10] The Griffon 61 series introduced a two-stage supercharger and other design changes: the pressure oil pumps were now housed internally within the sump and an effort was made to remove as many external pipes as possible.

According to A C Lovesey, who was in charge of the Merlin's development,[nb 3] "The impression still prevails that the static capacity known as the swept volume is the basis of comparison of the possible power output for different types of engine, but this is not the case because the output of the engine depends solely on the mass of air it can be made to consume efficiently, and in this respect the supercharger plays the most important role.

"[16] Unlike the Merlin, the Griffon was designed from the outset to use a single-stage supercharger driven by a two-speed, hydraulically operated gearbox; the initial production versions, the Griffon II, III, IV, and VI series, were designed to give their maximum power at low altitudes and were mainly used by the Fleet Air Arm.

[17] In 1946 a Griffon 101 was fitted to the Supermarine Spiteful XVI, RB518 (a re-engined production Mk.XIV); this aircraft achieved a maximum speed of 494 mph (795 km/h) with full military equipment.

[21] On takeoff, the throttle had to be opened slowly, as the pronounced swing to the right could lead to "crabbing" and severe tyre wear.

Early problems with the complex gearbox that was required for contra-rotating propellers prevented them from ever becoming operational in Spitfires, but they were used on later aircraft, including the Seafire FR.

The Royal Air Force Battle of Britain Memorial Flight is a notable current operator of the Griffon.