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).
Proposing modifications to the servo drive for the Spectre and Wraith models.
| Identifier | ExFiles\Box 95\4\ scan0100 | |
| Date | 8th November 1934 | |
| +4694 341 GRY{Shadwell Grylls} To EY. and RHC.{R. H. Coverley - Production Engineer} from RDY. c. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} Hs.{Lord Ernest Hives - Chair} Da.{Bernard Day - Chassis Design} Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} Servo Drive - SpectreCodename for Phantom III and Wraith. In view of the variation of the coefficient of friction of servo friction linings with temperature, as given in the Experimental Report Hs{Lord Ernest Hives - Chair}/FJH.{Fred J. Hardy - Chief Dev. Engineer}26.10.34, it is evidently important that the servo speed should be kept down to the minimum that can be satisfactorily used without having too much lag of the servo assistance for shunting. Therefore, we propose to modify the servo worm gears for both SpectreCodename for Phantom III and Wraith to give the same servo lag as now occurs on the Phantom. The pieces affected are the servo wormand wheel, the sleeve for the 1st speed wheel, the distance piece G.81871 and the speedometer drive gears and gearbox casing adjacent to them. Will you kindly hold up instructions for these pieces for the third SpectreCodename for Phantom III box and also for the Wraith. In the case of the SpectreCodename for Phantom III the need for an altered ratio of the servo drive, compared with that for the Phantom, is mainly due to the recent reduction of the axle ratio but in the case of the Wraith and Wraith-Bentley which have so far followed the 20/25, the reason for alteration is that the 20/25 has always had less lag than the Phantom. RDY. | ||