ROLLS ROYCE AND HIDUMINIUM MATERIALS
Rolls Royce maintained its own material standards pertinent to aircraft engine manufacture. On this page is a Rolls Royce factory document listing pre and WW2 ear materials with some hand written references to British Standards. On engines of RR manufacture RR materials are identified with proprietory series of letters and numbers stamped onto engine parts. I would welcome and documents or insights that help to explain this system.
Many of the alloys used in Rolls Royce and other engines were developed by High Duty Alloys Ltd, later incorporated into the Rolls Royce group of companies. The trade term Hiduminium is a contraction of the phrase ‘High Duty Aluminium’. The Hiduminium alloys were described with the prefix RR, eg RR50, RR58.
On this page is a Hiduminium document listing RR alloys with DTD equivalent specifications.
Hiduminium_DTD_British_Standard_Specifications
RR or Hinduminium alloys were generally used across the total British aircraft industry from the 1930’s until the present day and parts may often be found stamped with a Hiduminium material identifier. The author has sighted RR50 stamped on Armstrong Siddeley Cheetah engine crankcases used on the Avro Anson, as well as RR specifications for Gypsy Major engine conrods used in the Tiger Moth. Hiduminium alloys were used in the Concorde and continue to be used today.