Letter to Cadillac Motor Co. comparing the material specifications of Aerolite 122 and RR.53 alloys for pistons.
| Identifier | ExFiles\Box 170\2\ img175 | |
| Date | 16th November 1933 | |
| Experimental Dept. Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} 19/KT. November 16th 1933. M. {Mr Moon / Mr Moore} Olley Esq., The Cadillac Motor Co., Detroit, Michigan, U. S. A. {Mr Adams} Dear Oy., Further to my letter of Oct. 25th, I am sending you under separate cover a scrap Aerolite piston. It is 1 oz. lighter than the original ones we tested and has proved itself adequate for Bentley conditions in-so-far as mechanical strength goes. The Aerolite piston is not made in RR.53 alloy but in a high copper alloy. Comparing the two materials, the two specifications are as follows :- RR.53. Aerolite 122. Ultimate tons per sq.in. 23 18 Elongation % 1% Less than 1% Brinell-normal temp: 130 - 150 115 - 145 Brinell - at 300°C. 52 56 S.G. 2.75 2.9 Thermal Conductivity .40 .33 (C.G.S) Exp. Coefficient .000022 per °C. .000023 per °C. Therefore, if this piston was made in RR.53 alloy, it would be 1 oz. lighter besides being stronger at the higher temperatures. You will notice that they use a gudgeon pin without interference fit a thing we have not succeeded in doing up to date. cont'd | ||
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).