Interpreting material specifications dating back to the 1940s is a regular part of the work of Hercules Propellers, a specialist aircraft propeller design and manufacturing company based in Gloucestershire. One of their recent assignments was the replacement of critical parts from Spitfire propellers using drawings and specifications from the WW2 era.
“The original Rotol drawings and specifications date back to the 1940s and many of the materials used at the time are no longer available,” explains Victoria Sangwine-Gould, Operations Manager at Hercules Propellers.. “We were looking for an alternative to an obsolete DTD grade of bronze alloy that has no direct modern equivalent.”
Rotol was a joint venture between Rolls-Royce and Bristol Engines. Their propellers were installed on Spitfires in Britain from 1939 onwards. In 1958, Rotol became part of the Dowty group and Dowty Propellers is now part of GE Aviation Systems.
“We were fortunate enough to be advised by Columbia Metals that DEF STAN 02-833 would be a potential option to consider,” adds Victoria. “We purchased some 4” diameter material from the stockholder and we are very pleased with the results.”
For the replacement parts, the key requirements were high strength, high corrosion resistance and anti-galling properties. All these are recognised attributes of DEF STAN 02-833.
“Hercules are fortunate to be supported by Dowty Propellers who provide us with technical support and access to their vast archive of component drawings and specifications,” concludes Victoria. “Our design and production approvals, along with our in-house machining capabilities, enable us to produce all the parts for these propellers.”
About Hercules Propellers
Hercules Propellers are a manufacturer of propellers for a wide variety of aircraft types ranging from wooden First World War fighters to modern, composite racing aircraft. Established in 2008, the company specialises in wooden propellers with a unique blend of modern design capability and high-quality craftsmanship.
About DEF STAN 02-833
DEF STAN 02-833 is a nickel aluminium bronze containing aluminium as the major alloying element. This grade is primarily used for offshore and marine applications and offers high strength, excellent corrosion resistance in seawater and other aggressive media and high wear and abrasion resistance. Typical applications include marine valves, pumps, couplings, fasteners, gears and marine propeller shafts. Columbia Metals stocks DEF STAN 02-833 in round bar (3/8” to 10” diameter), hexagon, sheet, flat bar and square form.
