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).
Breakdown of weight savings for a Blown Phantom III engine.
| Identifier | ExFiles\Box 132\2\ scan0045 | |
| Date | 14th October 1938 | |
| 1115 also 350, 360/8 C O P Y. 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 | ||