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).
Tyre performance regarding 'shimmy', and issues with rubber engine feet and cylinder joints.
| Identifier | ExFiles\Box 45\2\ Scan087 | |
| Date | 28th September 1928 guessed | |
| contd :- -2- give us greater immunity from shimmy than the standard tyre on the 40/50. If so, they might help us in getting a good front end ride. It will be recollected that the 6" tyre was impossible on the Phantom, while Rapson 6.75" tyres with heavier treads than the Dunlops std. shewed considerably less tendency to shimmy. DUNLOPS FIGURES. | Type of tyre. | 20 HP. 20" RIMS. | | 40/50 HP. 21" RIMS. | | |---|---:|---:|---:|---:| | | Inflated dia. | Effective rolling rad: | Inflated dia. | Effective rolling rad: | | Present std: | 32.45 | 15.12 | | 17.5 | | Fort. | 33.17 | 15.47 | | 17.75 | | Super. | 33.3 | 15.55 | | 17.85 | | | | | 40/50 on 20") rims - Super) tyre. | 17.35 ) | RUBBER ENGINE FEET. The rubbers we have had in service experimentally have taken a slight permanent set after 6 months. This has only the effect of a somewhat weaker rubber and is not detectable until the engine foot is stripped. Messrs.Dunlops are improving the mix with a view to overcoming the trouble; we are testing to see if we can work with somewhat less initial set up. RUBBER CYLINDER JOINT. F.{Mr Friese}& H.{Arthur M. Hanbury - Head Complaints} ENGINES. After considering the exact location of the rubber ring and its initial compression of .013" diametrically, Dunlops are of the opinion that there is no possibility of the casting being broken by the rubber expansion due to 100°C temp: rise. This confirms our experiments. Dunlops have promised some exact information on the radial pressure to be expected from such a temperature rise. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||