Avro Lancaster B.II was a Bristol Hercules (Hercules VI or XVI engines) powered variant, of the Lancaster, 300 of which were produced by Armstrong Whitworth. A potential shortage of Rolls Royce Merlin engines resulted in a decision to install the Hercules. Once the allocation of Merlins to Lancaster production was assured, production of the B.II halted. Very early examples were fitted with an FN.64 ventral turret; however, these were quickly removed due to problems with aiming the turret through its periscope (which prevented the gunner from seeing a target he was not already aiming at), and inadequate traverse speed.
Avro Lancaster B.II PrototypeAvro Lancaster B.II PrototypeBristol Hercules Engine Installation on an Avro Lancaster B.II Avro Lancaster B.II Bristol Hercules engines InstallationAvro Lancaster B.II Avro Lancaster B.II, with Bristol Hercules engines, circa 1942.Flight Crew of an Avro Lancaster B.II Bristol Hercules Engine Installation on an Avro Lancaster B.II Avro Lancaster B.II RAF Linton-on-Ouse LL725 EQ-C, of 408 Squadron RCAFAvro Lancaster B.IIAvro Lancaster B.IIAvro Lancaster B.II DS848 QO R of No. 432 (Leaside) Squadron, RCAFAvro Lancaster B.IIAvro Lancaster B.II DS689Avro Lancaster B.II DS604 QR-W, of No. 61 Squadron RAF DS604 later joined No. 115 Squadron RAFAvro Lancaster B.IIAvro Lancaster B.II DS652 of 115 Squadron RAF 1943 KO-BAvro Lancaster B.II KO-A of 115 Squadron RAFAvro Lancaster B.II Operation Crossbow LL734 JI-O of 514 Squadron RAFAvro Lancaster B.IIAvro Lancaster B.II DS778Avro Lancaster B.II DS723 EQ-B of 408-Squadron RCAFAvro Lancaster B.II Powered by Bristol Hercules VI EnginesAvro Lancaster B.IIAvro Lancaster B.IIAvro Lancaster B.II DS669 KO-L of No 115 Sqn RAF rear turret with its gunner sheared off by bombs from aircraft raid on Cologne on night 28/29 Jun 43Crashed Avro Lancaster B.IIAvro Lancaster B MkII with a Metrovick F2 4 jet engine in its tail
