AVRO HERITAGE MUSEUM
Lancaster Propeller Blades
All Avro Lancasters versions were fitted with Rolls-Royce Merlin V12 engines with the exception of the Lancaster Mk.2 (B.II) which were fitted with Bristol Hercules radial engines. Rolls-Royce Merlin engines were manufactured by Rolls-Royce Derby and in shadow factories with their own Merlin Production lines in Crewe, Glasgow, most notably by Ford at Trafford Park, and by the American Packard Company.
Bristol Hercules engines were used to provide a war time alternative source of Lancasters in the event of a disruption in supply of Merlin engines by German bombing. They were made at their Bristol factories and at their shadow factory at Clayton-le-Moors, near Accrington in Lancashire
Lancaster Mk.1 were fitted with de Havilland type No. 5140 13 ft (4.0 m) diameter Hydromatic three-bladed propellers known as 'skinny' or 'pencil' blades manufactured from duralumin by de Havilland Propellers at Lostock near Bolton. From early 1944, when more powerful Merlin 22, 24, or 85 engines were fitted, the Nash-Kelvinator type A4/138 13 ft (4.0 m) diameter three-bladed propellers known as 'paddle' blades were used, which enabled an 8-mph increase in airspeed and an increased altitude of 1,500ft.
Lancaster Mk.3 with Packard built Merlins could be fitted with either de Havilland 'pencil' propellers or Nash-Kelvinator 'paddle' propellers. Some Lancasters may also have had Nash-Kelvinator 'paddle' propellers retrofitted to replace earlier de Havilland 'pencil' propellers.
Lancaster Mk.2 with Hercules radial engines were fitted with either de Havilland type No. 5140 13 ft (4.0 m) diameter Hydromatic three-bladed 'pencil' propellers manufactured at de Havilland Propellers at Lostock near Bolton, or Rotol propeller blades made of laminated and compressed wood known as the Jablo blade made by F. Hills and Sons, Ltd. Trafford Park.