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).
Proposed modification to the Phantom III tappet filter to extend its operational time before cleaning.
| Identifier | ExFiles\Box 96\2\ scan0272 | |
| Date | 9th November 1937 | |
| W/K.{Mr Kilner} To GWH.{George W. Hancock - Head Chateauroux} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} PHANTOM III TAPPET FILTER. We have tested out a scheme whereby the tappet filter can be run for a longer time before becoming sludged up. Before issuing a depot sheet, however, for this modification we would like to know what your experience is on the job, i.e. how often is it necessary to clean the filter ? If the intervals between cleaning are over long periods then the modification will not be worth while, on the other hand, however, if the filter frequently requires cleaning then the modification will be instructed as a depot sheet. The modification consists of a new banjo screw at the filter inlet and having a .100 dia. hole instead of the present 2 - .156 dia. holes. This reduces the oil flow at the high speeds which is excessive, by 50% and yet only reduces the flow at low speeds by 10%. By virtue of not having so much oil to deal with the filter stays cleaner over a longer period. Would like a reply as soon as possible. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||