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).
The friction within the Phantom automatic ignition advance mechanism and Watford magneto.
| Identifier | ExFiles\Box 48\2\ Scan437 | |
| Date | 13th March 1926 | |
| Expt. Report. X.8689. X8796 EFC {E. Fowler Clarke - Electrical Engineer} 2/T13.3.26. To R. {Sir Henry Royce} ) from EFC. {E. Fowler Clarke - Electrical Engineer} E. {Mr Elliott - Chief Engineer} ) c. to CJ. BJ. RG. {Mr Rowledge} c. to Wor. {Arthur Wormald - General Works Manager} Ds. Ry. PHANTOM AUTOMATIC IGNITION ADVANCE. X8796 X8796 (Ref. R2/N10.3.26). The friction in the advance and retard of the standard Watford magneto, which is equivalent to the force of about 3 lbs. weight either way at the end of the lever, has not been specifically desired from the point of view of preventing noise in the control linkages, but is a necessary concomitant of two things in the magneto :- (1) That we have to have the pressure of the contact breaker cover springs sufficient just to be in excess of the pressure required on the low tension terminal contact, in order to keep the end cover properly in place. and(2) That for the purpose of avoiding noise resulting from 'flopping' of the sleeve, we have had to arrange with Messrs. Watford for the sleeve bearings to be a particularly good fit. and of these two, perhaps the second one accounts for most of the frictional force required. In addition to the frictional force of 3 lbs. weight referred to, there is also an average hysteretic drag of the revolving armature on the sleeve which has to be overcome in advancing the magneto. The sleeve is subject to periodic magnetic impulses of rather large amount which are transmitted through the controls and are felt quite easily on the ignition lever. These impulses do not result in much Contd. | ||