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).
Instructions for production settings and experimental test results for Wraith shock dampers.
| Identifier | ExFiles\Box 9\8\ 08-page43 | |
| Date | 19th May 1938 | |
| Rm{William Robotham - Chief Engineer}/D.D.Clapham.7/WH.19.5.38. WRAITH SHOCK DAMPERS. SETTINGS INSTRUCTED FOR PRODUCTION. Front. Initial load 40 lbs. Leak 3 secs. in each direction obtained by drilling a hole .031" dia. throughthe valve. Rear. Initial load 40 lbs. Leak 2 secs. in each direction, obtained by drilling .046" dia. through the valve. Ride. The ride is good but there is a slight harshness at low speeds. It is very well controlled at the higher speeds, and a considerable increase in damping can be obtained by manipulating the hand control over hump back bridges or very wavy road surfaces. All the experimental Wraiths have the same setting to the front dampers as that which has been instructed for production. The leaks are measured by allowing a 10 lb. weight to fall through an arc of 22½° at the end of an arm 2' long. 24.G.VI. The rear dampers on this car do much less work on the bump stroke than on the rebound stroke. The settings are:- Initial load 40 lbs. each way. Leaks. Bump ½ sec. Rebound 4 secs. The rebound leak is obtained by drilling the valve .031" dia., and the additional bump leak by drilling a hole .080" dia. through the upper part of the bump piston into the reservoir. Ride. The resulting ride is very soft, and the dampers seem to allow excessive up and down movement to occur occasionally. There is hardly sufficient build up with the control in the hard position to cope with wavy surfaces at high speeds. | ||