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).
Table outlining weight savings for a blown Phantom III engine.
| Identifier | ExFiles\Box 96\4\ scan0140 | |
| Date | 14th October 1938 | |
| 358 also 1115 and R-65 C O P Y. 14/10/38. WEIGHTS FOR BLOWN PHANTOM III.ENGINE SHOWING POSSIBLE SAVINGS. | | lbs. | ozs. | |---|---|---| | Weight Standard P.III Engine complete with solid rockers (less fan) | 805 | | | Saving in weight possible: | | | | Removal of Fan pulley . . . . . . . . . . | - 1 | 1 | | " " Clutch case . . . . . . . . . | - 10 | 13 | | Deletion clutch & trunnion mechanism . . . . | - 55 | 13½ | | " slipper wheel front half . . . . . . . . . | - 9 | 1½ | | " " " rear half . . . . . . . . . | - 7 | 15½ | | " flywheel . . . . . . . . . . . . . | - 27 | 9 | | " carburetter . . . . . . . . . . | - 9 | 4 | | " air silencer . . . . . . . . . . . | - 4 | 9½ | | Lower half in Magnesium saves . . . . . . . . . | - 8 | 8 | | Light cylinder liners save . . . . . . . | - 7 | | | Magnesium wheelcase saves . . . . . . . . | - 1 | 13 | | " rocker covers save . . . . . . . . . | - 3 | 1 | | Bringing the weight down to . . . . . . . | 658 | 7 | | Leaving off the Dynamo & Self-starter saves | 62 | | | Reducing the weight to . . . . . . . . . . | 596 | 7 | | ||