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).
Report page discussing engine advance curves, spring ratings, and governor design.
| Identifier | WestWitteringFiles\H\March1922\ Scan42 | |
| Date | 27th March 1922 | |
| Contd. -4- EFC1/T27.3.22. represents a spring which allows the cam to advance 23° from 0 to 1500 R.P.M. Actual corresponding curves of advance are shown marked I and V on the sheet of advance characteristics. The dotted curves marked 1 and 2 on the big sheet are curves of actual advance observed by the instantaneous vision method, only in these two cases though the rating of the spring is approximately the same as for I and V, the set was such that the advance from the stop provided, did not begin until a speed in the neighbourhood of 375 R.P.M. Lines corresponding to these curves 1 and 2 have been drawn on the diagram and the similarity is found to be very near, indicating that the estimation of the advance curve from the ideal diagram is quite a reasonably reliable method of obtaining an actual advance characteristic. Comparing these curves I and V and 1 and 2, with curve B on the sheet of curves, which represents the characteristic of advance required by the engine, namely, an advance of 11° from 0 to 250 R.P.M. and of 12° at a reducing rate from 250 to 1500 R.P.M. and of [crossed out text] we at once see that it is quite impossible with this design of governor to obtain the desired curve. Of the remaining curves labelled A, B, II, III, and IV, these were plotted as an aid to considering how best to attain the 12° portion of advance from 250 to 1500 R.P.M. only. If this is all the governor is required to do, then it is possible to select from the total range of motion of the Contd. | ||