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).
Letter to Cadillac discussing the testing and performance of aluminium pistons and the R.R.53 alloy.
| Identifier | ExFiles\Box 170\2\ img170 | |
| Date | 25th October 1933 | |
| Experimental Dept. HS{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}7/KT. Oct 25th 1933. M.{Mr Moon / Mr Moore} Olley, Esq., The Cadillac Motor Car Co. Detroit, Michigan. Dear Cy, Many thanks for your letter of the 10th. We had Messrs. Seaholm and Thompson at the works and tried to show them what we are doing. They tried a Phantom and one of the Bentleys. We enjoyed their visit. I understood from Seaholm that you are going over to aluminium pistons. We have just been testing what we consider to be a very promising aluminium piston produced by the Light Production Co. Ltd., 60/66 Rochester Row, Westminster, S.W.1, and we enclose a drawing of a piston they made for our 20/25. We have "flogged" this piston unmercifully. It is very good for power, being perhaps 4% up on the split skirt type. We think there is no doubt that it can be made reasonably free from cold knocks, but in every engine a certain amount of experiment has to be made to get exactly the correct form. One value of the piston is that it does not rely on flexibility at all, it is so proportioned that it maintains approximately the same shape hot or cold. We have not as yet had sufficient running to say that this piston is as free from cold knocks as the split skirt type. The best alloy we know of for pistons is our R.R.53; we enclose a specification of this material. The piston as made to this drawing is a little heavy. It is actually designed to run at over 5000 r.p.m. We have run a 20 hours endurance test full throttle at 4000, 4250, and 4500 r.p.m. on these pistons, approx. 14 hrs. being at 4500, developing about 100 H.P. at 3 1/4 litres. | ||