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).
Modification to the governor control dampers to improve performance during severe braking.
| Identifier | ExFiles\Box 151\2\ scan0293 | |
| Date | 13th June 1935 | |
| To E. {Mr Elliott - Chief Engineer} c. to Hdy. {William Hardy} c. to Da. {Bernard Day - Chassis Design} c. to Hy. {Tom Haldenby - Plant Engineer} c. to Wor. {Arthur Wormald - General Works Manager} X179 Severe Braking with Governor Control Dampers (Minimum Damping). During severe braking the load of our dampers diminishes right down to the fixed initial settings, due to (a) the slowing of the governor from the reduction of speed of the car, (b) momentary stopping of the governor when rear wheels are locked during emergency braking, the result being that with emergency braking both axles dither badly and the car is difficult to control. To overcome this feature we have fitted a 4 oz. weight on to the bottom of a 5.4" long lever attached to the over-riding control spindle on the governor unit. This means that with severe braking the inertia of the pendulum causes the lever to move over to maximum damping. On the road we find that this device adds largely to the controllability of the car with really violent braking. The lag in building up pressure in the unit does not give full damping immediately the brakes are applied, but it does prevent any chance of the pressure diminishing. Actually it is found that the pressure does increase slightly. The following governor pressure figures were taken from 25-HX., the brakes being applied at 73 m.p.h. and the wheels being locked about 50 m.p.h. | Speed | 73 m.p.h. | 45 m.p.h. | 5 m.p.h. | |---|---|---|---| | Gov. Press. Standard. | 18 lbs/sq.in. | 2 lbs/sq.in. | 0 lbs/sq.in. | | Gov. Press. with Inertia Control. | 18 lbs/sq.in. | 25 lbs/sq.in. | 25 lbs/sq.in. | | ||