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 braking ratios and efficiency of a servo unit referred to as the 'India' unit.
| Identifier | ExFiles\Box 5\3\ 03-page137 | |
| Date | 27th May 1925 | |
| EXPERIMENTAL REPORT. -3- Expl. No. REF: Hs{Lord Ernest Hives - Chair}/Rml/L.G27.5.25. have When we/tested more servos we shall be in a better position to give a mean value for the multiplication of the 'India' unit. We are carrying out investigations to determine why the original servo was less efficient than that which we have just tried. With reference to the second portion of your DA{Bernard Day - Chassis Design}2/M25.5.25. We cannot understand how the proportion of servo braking which is sent to the front brakes will vary with the weight of the car. We should like to point out that to increase the braking units available, the pedal pressure must be increased and this increases the direct braking. For any increase in total braking units available, the ratio of direct pedal, servo front, and servo rear, remain a constant for any given servo multiplication. Thus for 'India' at present the ratio for a servo efficiency of 1 are - Direct : servo rear : servo front - as 35 : 405 : 481 quite irrespective of the weight of the car. Quoting from your memo. "For example, if we take the 'India' distribution of braking as 25 direct braking, 25 to rear, 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 contd :- | ||