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).
Recommendation to use a harder rubber for semi-isolation bushes and washers, as the current material is too soft.
| Identifier | ExFiles\Box 14\5\ Scan145 | |
| Date | 6th February 1930 | |
| To Ey. From Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} c. to Da.{Bernard Day - Chassis Design} c. to RV. Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} 2/W.6.2.30. x 7005 x 6b13 We think that the semi isolation rubbers, bushes etc., are made of material which is too soft. We attach a sample of rubber which we recommend, which should be used for all bushes and washers on the semi isolation job. There is no reason why the present supply of soft rubbers should be scrapped as there may be coachbuilders with booming bodies who prefer to use them, but we are satisfied that the harder rubber is an improvement in almost every case. The harder rubber is one of the mixes supplied for the 40/50 engine feet and is produced by Messrs. Dunlop and Co. Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} | ||