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 specifications for a Spectre model's propeller shaft.
| Identifier | ExFiles\Box 94\4\ scan0103 | |
| Date | 16th June 1934 | |
| X4694 337 To RM.{William Robotham - Chief Engineer} from Da.{Bernard Day - Chassis Design} c. Wor.{Arthur Wormald - General Works Manager} Mr. Hs.{Lord Ernest Hives - Chair} Roy.{Sir Henry Royce} RMD. Da.{Bernard Day - Chassis Design}1/HP.16.6.34. SpectreCodename for Phantom III propeller shaft. With reference to Da.{Bernard Day - Chassis Design}2/HP.14.5.34, the use on the first car of the temporary J.S. gearbox causes the propeller shaft to be 2" longer than the 48.375 required with the final gearbox. If the diameter is kept 2.625, this causes the whirling speed to fall from 7150 to 6610 r.p.m., Bentley being 6970. For the first car it would therefore appear desirable to use a shaft 2.750 dia. x .104 thick, giving a whirling speed of 6950. The max smooth r.p.m. on Bentley is said to be 4300 - 89.6 m.p.h. - with initial roughness - 4500 & 94 respectively. Corresponding figures on SpectreCodename for Phantom III will be - 4285 - 101 m.p.h. and 4470 - 106.2 m.p.h. Da.{Bernard Day - Chassis Design} | ||