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).
Comparison table of servo and brake particulars for different car models.
| Identifier | ExFiles\Box 179b\2\ img058 | |
| Date | 3rd November 1932 guessed | |
| SERVO AND BRAKE PARTICULARS | | 40/50 | 20/25 | PERF. | |---|---|---|---| | CAR WEIGHT | 48 CWT | 35 CWT | 28 CWT | | BRAKE UNITS FROM BRAKING | R | 272 x S | 220 x S | 188 x S | S = TORQUE MULTIPLICATION | | | F | 227 x | 304 x S | 195 x S | | SERVO TORQUE MULTIPLICATION | FOR µ = .2 | 2.53 | 1.55 | 1.28 | | = 2µ / {µ + FABRIC COT λ / 2 CAM} | | | | | | TAKING INTO ACCOUNT ROAD WHEEL DIA. | | | | | | BRAKE UNITS PROP. TO | 38 | 26 | 17 | | FOR SAME DECELERATION | | | | | | PEDAL PRESSURE REQUIRED | 100 | 106 | 130 | | END THRUST ON SERVO | 1030 | 742 | 1030 | | AREA OF SERVO LINING | 12.2 | 8.7 | 5.5 | | UNIT PRESSURE (P) | 85 | 85 | 188 | | RUBBING VEL FOR SAME CAR SPEED | | | | | | PROPORTIONAL TO (V) | 5 | 5.7 | 5.6 | | PY | 42.5 | 48.5 | 105 | HEATING PROP. TO THIS | | LINEAR MOVEMENT OF SCISSOR LEVER | | | | | | FOR 1" MOVEMENT OF REAR BRAKE CAM | .83 | .57 | .59 | | ANGULAR MOVEMENT | 4.05 | 3.23 | 3.95 | | NOTCH ADJUSTMENT | 5° | 5° | 6° | | ANGULAR MOVEMENT OF SCISSOR LEVER FOR 1 NOTCH | 20.3° | | 15.4° | | ||