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).
Requesting the casting of sample pistons in EX.70 alloy to test its casting properties and strength.
| Identifier | ExFiles\Box 148\3\ scan0076 | |
| Date | 12th June 1933 | |
| X2748. To-Hl. from E.{Mr Elliott - Chief Engineer} c. Sg.{Arthur F. Sidgreaves - MD} Wer. Hs.{Lord Ernest Hives - Chair} By.{R.W. Bailey - Chief Engineer} E.3/HP.12.6.33. Pistons in EX.70. We should like you to cast one or two sample pistons in EX.70 to detail No.EB.495/Bensport Piston, for which there is now a set of dies, so that you can satisfy yourself as to the casting properties of this metal. We should also like to have exact information as to the strength of EX.70 hot in the die cast condition compared with our standard RR. piston alloy. We are keenly interested in developing a low expansion piston alloy, and as EX.70 would allow us to reduce piston clearances on account of its expansion being .7 of the present material, we are hoping it will provide an avenue of development in this direction. The advantages we expect to gain are increased area of bearing surface on the piston skirt, and at the same time an improved metal from the point of view of being a bearing surface, and also last, but not least, less liability to cold taps or knocks. E.{Mr Elliott - Chief Engineer} | ||