From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Explaining the cause of Bentley piston failure due to incorrect material being used in their manufacture.
| Identifier | ExFiles\Box 82\1\ scan0062 | |
| Date | 27th March 1933 | |
| X4853a. G.W.Hancock, c/o Hotel de France, Chateauroux, Indre. FRANCE. GWH.{George W. Hancock - Head Chateauroux} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} 9/KT. 27.3.33. We found that the cause of the failure of the Bentley pistons E.56610 which you have now removed from the car, was due to their being made in the wrong material. For some reason they were made in crankcase alloy which has only a tensile strength of 3 tons/sq.in. at piston temperatures. The proper piston meterial has a tensile strength of 10 tons/sq.in. at piston temperature, and so it is improbable that there whill be any further failures. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||