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,[23] 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.[24] 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.[25]