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 design and testing of a distributor, including measurements and endurance test results.
| Identifier | WestWitteringFiles\F\May1921\ Scan41 | |
| Date | 4th May 1921 | |
| R.R. 285A (100 T) (S.H. 79S. 10-12-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2947 -2- EFC4/T4.5.21. Contd. (2) For remarks re mechanical and electrical design see preliminary report. (3) The radial air gap was unobtainable. (4) H.T. safety gap 8.5 mm. This is slightly less than that obtained on the Z.R.6. (5) Distributor dimensions are according to sketch herewith. It will be seen that they are about the same as on the Z.R.6. (Sketch with dimensions: .845", 1.477", x, .30") Overlap x at advance = .20" " " retard = .46" (6) Referring to the position of maximum armature flux at dead slow, as datum position, we found that the make occurred 38° and 23° before this position for the advance and retard respectively. The maker's range was found to be 35° so that the corresponding breaks occurred at 98.5° and 133.5° respectively, giving a make ratio of .870. The platinum point gap we found to be .016", which with the timing was not unreasonably affected by our running tests and by varying the platinum point gap ± .004". These figures are similar, with the exception of the platinum point gap which is rather larger on the Z.R.6. That machine also has a little wider range. (7) Results of short endurance test (12 hours) at 2,000 r.p.m. sparking on a set of 5.5 mm. gaps in air with timing lever central. After running 10.5 hours, the distributor gear bearing seized up. There were distinct signs of tracking in the distributor, with Contd. | ||