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).
Analysis of a governor mechanism's performance and discussion of alternative designs.
| Identifier | WestWitteringFiles\H\March1922\ Scan44 | |
| Date | 27th March 1922 | |
| Contd. -6- EFC1/T27.3.22. tremendously as the spring is compressed, which action is not possible with any single spring. Any possibility of a single spring working over a selected range can be readily tried out in a similar manner. Although it appears at first sight that the required motion of the weights in the governor as originally arranged should be rapid at first and slow afterwards, this is explained physically to be by no means the case, because unless the weights get very nearly round to the 90° position (which is physically impossible with the twin system we have) the rate at which the dynamic couple falls off due to increasing angle is very much more than made up for by the increase due to increasing speed, it being remembered that the effect for a given angle is proportional to the square of the speed. We hope the above will be sufficient to show you that the present design of governor gets nowhere near doing what we want it to do, and particularly so if we wish it to do the whole of the advance as represented by the curve B. We are not attempting to suggest any details of a design which would give the required characteristic, but it seems likely that if we use the centrifugal principle, it would be necessary to use a variable motion ratio (e.g. crank motion to piston motion) between the centrifugal system and the advancing cam, or else some sort of compound leaf spring with very variable rating. We fear that it would be very difficult in any case | ||