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).
Testing and comparison of different rear damper settings and modifications.
| Identifier | ExFiles\Box 9\8\ 08-page44 | |
| Date | 19th May 1938 | |
| -2- 24.G.VI. - Cont'd.{John DeLooze - Company Secretary} The reason for not standardising these settings is that the uneven leak allows free movement of the damper owing to the fact that on the bump stroke most of the oil is passed into the reservoir, and therefore the replenishing valve has to pass the same quantity of oil to the other end of the cylinder, and this is impossible with a small valve in its present position. Further, the replenishing valve might give trouble as it has more work to do, and it has not been tested. This slack movement causes the ride to be too soft. 26.G.VI. The rear dampers on this car have the same setting as 24 but obtained in a different way (B.408). They have been tested in France for 15,000 miles. A tube is inserted into the pistons joining them in such a way that oil passing through the .080" hole in the lower part of the piston passes through the tube and a spring loaded ball valve at the other end into the other end of the cylinder. The ball valve prevents the passage of oil along this duct on the rebound stroke. The interlever has to be milled out to avoid the tube. Ride. It is generally agreed that 26.G.VI has the best ride of any Wraith. It is very soft but neither up and down movement nor pitching is allowed to become excessive. These modifications eliminate the free movement of the damper but we do not want to standardise them on the score of expense, besides which they have not been bumped. There is the possibility of fidgeting of the connecting tube in the pistons, and leakage. 29.G.VI. The rear dampers on this car have the same setting as 24 obtained in still another way (SCD.314). The .080" dia. hole in the bump piston leaks into the reservoir but larger replenishing valves are used. They are the same type as used on Bentley III front dampers. This modification has eliminated the free movement of the damper, and the ride is very good, as good as 26.G.VI. Unfortunately, the large replenishing valves cannot be standardised because they have Cont'd.{John DeLooze - Company Secretary} | ||