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).
Investigation into a Wraith's harsh ride, focusing on the governor unit and damper pressures.
| Identifier | ExFiles\Box 9\8\ 08-page57 | |
| Date | 28th November 1938 | |
| 642- Da.{Bernard Day - Chassis Design} from Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} c. Da{Bernard Day - Chassis Design}/Hdy.{William Hardy} Rm{William Robotham - Chief Engineer}/AFM{Anthony F. Martindale}6/R.28.11.38. WRAITH GOVERNOR UNIT. We have had a Wraith in from Sales during the week-end with the complaint of harsh ride. The car has now been returned to them. We found that the pressure from the damper unit was 20 lbs/sq. in. at 30 m.p.h. instead of 3½ lbs. We rectified this by increasing a washer thickness by .006". We also noticed that the degree of tightness of the nut on the end of the governor valve affected the pressure. We consider that this adjustment is far too sensitive. We also noticed that temperature of the governor unit reduced the max. pressure from 34 lbs/sq.in. to 22 lbs/sq.in. This is a bad feature. The unit appears to need investigation, and this will be done in two or three weeks' time when the work being done on B.V. unit pressure-velocity effect is finished. The Wraith front end is extremely sensitive to damper pressures, 40 lbs "ball pin" load being all a Wraith will stand from the front shock dampers without introducing harshness at low speeds, whereas B.V. will stand 125 lbs. without trouble. This peculiarity makes it impossible to get a really good ride on Wraith. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} | ||