contra-rotating propellers. 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. Pilot transition Pilots who converted from the Merlin to the Griffon-engined Spitfires soon discovered that, because the Griffon engine's propeller rotated in the opposite direction to that of the Merlin, the fighter swung to the right on takeoff rather than to the left. This tendency was even more marked with the more powerful 60- and 80-series Griffon engines, with their five-bladed propellers. As a result, pilots had to learn to apply left (port) trim on takeoff, instead of the right (starboard) trim they were used to applying. On takeoff, the throttle had to be opened slowly, as the pronounced swing to the right could lead to "crabbing" and severe tyre wear. Some test Spitfire XIVs, 21s, and 24s were fitted with contra-rotating propellers, which eliminated the torque effect. 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. Mk 46 and F and FR.47, which were fitted with Griffon 87s driving contra-rotating propellers as standard equipment. The Griffon 57 and 57A series, installed in Universal Power Plant (UPP) installations and driving contra-rotating propellers, was used in the Avro Shackleton maritime patrol aircraft. Variants The Griffon was produced in approximately 50 different variants, the Griffon 130 being the last in the series. Details of representative variants are listed below: Griffon IIB 1,730 hp (1,290 kW) at 750 ft (230 m) and 1,490 hp (1,110 kW) at 14,000 ft (4,270 m); Single-stage two-speed supercharger; impeller diameter 10 in (25.4 cm); gear ratios 7.85:1, 10.68:1. Used on Firefly Mk.I and Spitfire XII. Griffon VI Increased maximum boost pressure, 1,850 hp (1,380 kW) at 2,000 ft (610 m); impeller diameter 9.75 in (24.7 cm). Used on Seafire Mk.XV and Mk. XVII, Spitfire XII. Griffon 57 and 57A 1,960 hp (1,460 kW); 2,345 hp (1,749 kW) with water-methanol injection on take-off: used on Avro Shackleton. Griffon 61 Introduced a two-speed two-stage supercharger with aftercooler similar to that on Merlin 61; 2,035 hp (1,520 kW) at 7,000 ft (2,100 m) and 1,820 hp (1,360 kW) at 21,000 ft (6,400 m); used on Spitfire F.Mk.XIV, Mk.21. Griffon 65 Similar to Griffon 61