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).
Servo braking efficiency and distribution in relation to car weight.
| Identifier | WestWitteringFiles\M\2April1925-June1925\ Scan90 | |
| Date | 1st May 1925 guessed | |
| (2) "Incidentally in the instructions given in " HS{Lord Ernest Hives - Chair}1/LG9724. for testing the EAC.3. servo effic- " iency, it appears that the ratio of rod loads " is expected to come within the limits given on " the diagram of braking, which is in terms of " servo torque." We should also like to point out that the proportion of servo braking which is sent to the front brakes will vary with the weight of the car, and will always become a greater proportion with the lighter car. For example, if we take the India distribution of braking as 25 direct braking, 25 to rear, and 25 to front, that is, the ratio of front to back is 1 over 2., the ratio of the servo braking to front and rear is 1 over 1. Taking a car of twice the weight, instead of 75 total units of braking being available, there are now 150., and keeping the distribution of braking the same namely, front is to rear as 1 over 2., then the total units to the rear are 100., the total units to the front are 50., and of the 100 to the rear 25 is direct braking, as on the lighter chassis. In this case it will be seen that the servo ratio front to back is 50/75. If this were carried still further, and a car of half the India weight were considered, the direct foot braking remaining 25., it would be seen that the whole of the servo must be sent to the front. DA.{Bernard Day - Chassis Design} | ||