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 investigation and testing of Wraith ride characteristics and damper settings.
| Identifier | ExFiles\Box 9\5\ 05-page237 | |
| Date | 11th January 1939 | |
| 646 To By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Mx.{John H Maddocks - Chief Proving Officer} c. to Da{Bernard Day - Chassis Design}/Ev.{Ivan Evernden - coachwork} Rm{William Robotham - Chief Engineer}/Clm.{D. D. Clapham}4/JH.11.1.39. Wraith Ride. After a thorough investigation into the ride of 'C' series Wraith, we have come to the conclusion that the settings for 'A' and 'B' series are also best for 'C' series. These settings are :- Front. Initial load 40 lbs. Leak 3 secs. Rear. Initial load 40 lbs. Leak 2 secs. The governor unit should also have the same characteristics as heretofore. The faults which we set out to try and cure were that on the open road the front of the car maintains a continuous up and down movement and that there was an unpleasant pitching tendency over certain types of road surface such as opposite Normanton recreation ground. Since Bentley V does not need controlled front dampers, we first tried decontrolling the front dampers and increasing the initial load to 100 lbs. Despite several alterations to leaks, steering joggles were bad, and also front end shake so we formed the opinion that we had got too much damping, especially at low speeds. We, therefore, returned to controlled front dampers, and tried a larger bellows to give more damping at high speeds but again we ran into front end shake so we were forced to the conclusion that the front end of the Wraith frame is not strong enough to have more damping than it has at present. The increased front damping did stop the continuous up and down movement, and the pitching tendency, but these improvements were more than offset by the front end shake. The tests were carried out on 29.6.VI. Rm{William Robotham - Chief Engineer}/Clm.{D. D. Clapham} | ||