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).
Oil consumption comparing Mobil-Arctic and Castrol XL oils, and issues with clutch performance.
| Identifier | ExFiles\Box 130\2\ scan0340 | |
| Date | 8th December 1936 | |
| 1113 Rm.{William Robotham - Chief Engineer} from Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} Rm{William Robotham - Chief Engineer}/GWH{George W. Hancock - Head Chateauroux}3/R.8.12.36. 35-EX. Oil Consumption using Mobil-Arctic Oil. The oil consumption on P.III in service is not too good, using Castrol XL. There are a number that are averaging 500 M.P.G. If these owners at our recommendation use Mobil-Arctic, there will be complaints. 35-EX averaged 947 M.P.G. using XL. under traffic conditions; with Mobil-Arctic 634 M.P.G. On the run from London to Derby at an average speed of 47 M.P.H., the consumption dropped to 404 M.P.G. During the run up I was not at all impressed with the smoothness of the engine, and the engine noise was more noticeable. At times on the over-run a bad period of roughness developed. CLUTCH. When cold the engagement of the clutch is good, but immediately it warms up, it becomes fierce and jaggers. It has deteriorated considerably within the last week's running, and would not be accepted by an owner. Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} | ||