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 efficiency and reliability of cone type versus plain plungers.
| Identifier | ExFiles\Box 168a\2\ img415 | |
| Date | 11th March 1939 | |
| -2- Tests may then be carried out to determine the most efficient arrangement. Although the cone type plunger adds to the efficiency in respect to constancy of magnetic pull over a given length of travel, too steep an angle will tend to cause failure, due to bending in the core, if the plunger is not evenly centred. In view of the above we favour either 30° cone or a plain plunger, which we consider, will give greater reliability, in that the detrimental effects due to eccentricity of the plunger or wear of the guide, will be greatly reduced. RM{William Robotham - Chief Engineer}/KC. | ||