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).
Explanation of a diagram used to derive advance curves for governor weights using different springs.
| Identifier | WestWitteringFiles\H\March1922\ Scan41 | |
| Date | 27th March 1922 | |
| KFCL/T27.3.22. -3- Contd. to the fact that, other things being the same, the couple exerted is proportional to the square of the speed, the heights of the vertices of these curves above the base line are also in this proportion. For the purpose of arriving at the results, it is not necessary to consider the actual magnitude of these couples. Therefore, we have shown a vertical scale of arbitrary units. The control of the moving system of weights being by means of a spring must necessarily be represented on this diagram by some straight line, the slope of which is represent-ative of the rating of the spring and the intercept of which on the vertical axis (representing the zero angular position) is the amount of set up of the spring (in this position. Thus, any sloping straight line which we choose to draw across the diagram represents a possible spring. The use of this diagram is that the type of advance curve given by any kind of spring for any selected range of motion of the governor weights can be readily derived and plotted as we have done on the sheet of curves for a number of cases. Taking any one straight line, the intersections of this with the family of half sine curves give the angular position of the governor weights when in dynamical equilibrium with the control for each of the various speeds taken. Line I, for instance, is representative of a spring which allows the cam to start advancing at 250 R.P.M. and advance 24° up to 1500 R.P.M., whilst line V similarly Contd:- | ||