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).
Concluding recommendation on the regular renewal of castor oil-based hydraulic fluids.
| Identifier | ExFiles\Box 140\2\ scan0177 | |
| Date | 31th March 1939 guessed | |
| - 2 - Finally it is our contention that as in all hydraulic fluids containing castor oil, it is essential to renew the whole system with clean new fluid at least every 6-12 months, and that unless this is done, the trouble is always likely to occur, as all these fluids deteriorate with time. (sgd) W.R.Franklin. | ||