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).
Required properties of friction materials for a servo mechanism.
| Identifier | WestWitteringFiles\L\Jan1924-March1924\ Scan180 | |
| Date | 4th March 1924 | |
| ORIGINAL R.R. 235a.(100 T) (S.R 159. 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2500 TO HS.{Lord Ernest Hives - Chair}) FROM R.{Sir Henry Royce} DA.{Bernard Day - Chassis Design}) SECRET. R2/M4.3.24. E.{Mr Elliott - Chief Engineer} A.C. Copy to - CJ. " " - RG.{Mr Rowledge} " " - BY.{R.W. Bailey - Chief Engineer} re. FRICTION MATERIALS FOR SERVO. Y9910 This requires a material whose chief advantage is consistency under all conditions, which means wearing well, the same worn and new, not damaged by temperature, damp or dry, and preferably not affected in life and efficiency by oil. I do not think it matters if the co-efficient is high or low within reason, so much as that it shall be thoroughly reliable. R.{Sir Henry Royce} | ||