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 modification and adjustable load settings for Phantom II hydraulic shock absorbers.
| Identifier | ExFiles\Box 16\4\ Scan111 | |
| Date | 1st October 1929 | |
| X7520 To Hm.{Capt. W. Hallam - Head Repairs} from Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} For Depot Sheet. Hs{Lord Ernest Hives - Chair}/anl/ADS.10.29. PHANTOM II HYDRAULIC SHOCK ABSORBERS. As pointed out in the Depot Sheet for suspension the hydraulic dampers on Phantom II have been modified so that the loadings of both the high and low pressure valve can be altered without removing the damper from the frame. The cars are despatched from the Works with a front load of 70-lbs up and 80-lbs down, and a rear load of 80-lbs up and 85-lbs down. These loadings have been arrived at by tests on both the Continent and in England. Naturally for people who always use their cars on the Continent and drive at high speeds higher loadings may be desirable, while for customers who rarely exceed 40 miles per hour a reduction in the loading will be found beneficial. For this reason the dampers are so arranged that by changing the washer under the valve cap the loading can be altered. The front shock absorber valve caps can easily be got at by lifting the bonnet. The attached curve shows that they are sent out with .040 in the high pressure cap and .060 in the low pressure cap. We recommend that where any alteration is found necessary 50-lbs should be considered a minimum load, while 100-lbs can be obtained by taking all the washers from under the valve cap. The attached curve shows the intermediate loads that can be obtained by various washer thicknesses. On the rear it is not very easy to get at the high pressure valve cap and a special spanner is provided to facilitate this operation. It will be seen from the attached curve that by altering washers the ball pin loads from 105-lbs to 55-lbs are obtainable. This should be a sufficiently wide range to cater for general requirements. It is essential that a minimum loading of 50-lbs should be retained on front shock absorbers to prevent the possibility of high speed wobbles occurring. Whenever the front shock absorber load is reduced, the steering of the car should be tested at high speeds with 30-lbs front tyre pressures to ensure there is | ||