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).
Letter clarifying that piston groove leaks in dampers are an intentional design feature.
| Identifier | ExFiles\Box 101\2\ scan0165 | |
| Date | 12th November 1936 | |
| 500u To GWH{George W. Hancock - Head Chateauroux}/H.F.Hamilton. C/O Hotel De France, Chateauroux, Indre, FRANCE. Rm{William Robotham - Chief Engineer}/Les.18/AP.12.11.36. 22.G.V. Re your note of November 9th. It appears that you have been thoroughly mislead by the piston groove leaks. All our dampers have grooves in the pistons to avoid a pressure building up in the damper. Actually with the extended 4 ft. lever it is hard to check the high pressure damper loads with out fitting solid pistons. All production damper valves are set with solid pistons. This leak through the grooves gives a pure pressure velocity characteristic so does not reduce the effectiveness of the damper. Actually we are liable to copy the Americans and increase this leak. It appears from your note that the leaks on the dampers vary considerably. If you do have to block up grooves in order to check the really high loads, do not forget to open the grooves before re-fitting the dampers, as this greatly ruins the riding qualities. Rm{William Robotham - Chief Engineer}/Les.{Ivan A. Leslie} | ||