HK Models 1/48 Avro Lancaster B Mk.I HK01F005History of the Avro Lancaster From failure to success. The four engine Avro type 683 Lancaster was developed from the disappointing twin engine Manchester, which suffered from engine res caused by its unreliable Rolls Royce Vulture engine installation. However, the basic Manchester airframe was of sound design. A logical solution was to increase the wingspan and replace the two Vultures with four Merlin engines. The engine installation originally