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).
Design and requirements for petrol filters on Phantom and Goshawk models.
| Identifier | WestWitteringFiles\N\2July1925-September1925\ Scan106 | |
| Date | 29th September 1925 | |
| R.R. 235A (100 T) (S.H. 159. 11-3-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 TO HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} [Struck through text: Captain Gill, B.H.H.] [Struck through text: BY.{R.W. Bailey - Chief Engineer} DA.{Bernard Day - Chassis Design}] ORIGINAL. R3/M29.9.25. X3701 X 8190 PHANTOM AND GOSHAWK PETROL FILTERS. The following are the points we are instructing:- The autovac openings both to the air and the induction pipe to be protected by fine gauze so as to keep dust etc entering at these two points. The filter on the carburetter is made more robust in the rod tightening on the cover. The filter should be 160 mesh. It is of ample size because no quantity of dirt should get to this point. It is only there for safety. The outgoing filter in the main tank should be a very large size, easily removable without damaging the paint, and arranged for a double level instead of the spare compartment. For the Phantom it is 20 times larger than the outgoing Silver Ghost, and 6 times the present. We consider the ingoing filter is not practical, as it will not pass the petrol quickly enough, unless impracticably bulky, and even then should it be partly stopped up it will be always in disgrace and judged too small. We do not want too many filters, and the 2 mentioned, with a sump for dirt and water, are all that are needed. The blocked jets cannot be blamed to the absence of the ingoing filter, and the blocked outgoing filter can definitely be blamed to this being insufficiently large. Providing there is an efficient outgoing filter in the tank, and a filter on the carburetter, there should be no stopped jets unless the filters are defective, or it is impossible for filters to protect the jets. We have abandoned the double compartment idea because of the difficulty in gauging the petrol, and removing the petrol. We agree that a large sump is desirable to collect dirt and water. This is arranged. There have apparently been 3 errors in the past - (1) Gauze on the carburetter filter has not been fine enough. (2) Gauze in the outgoing filter of the tank requires to be enormously larger and more convenient for removal. (3) Care also must be taken that dirt cannot pass the fittings, by imperfect diametral fits. Some of the statements made are hardly correct: the Silver Ghost outgoing filters were very small area, and often failed. We shall now have a more perfect arrangement than we have ever had - i.e. free and convenient filler, and larger sump for dirt (1) | ||