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).
Engine mounting modifications to reduce frame jellying and the resulting vibration issues.
| Identifier | ExFiles\Box 104\3\ scan0094 | |
| Date | 15th May 1929 | |
| Y5360 To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} Hs{Lord Ernest Hives - Chair}2/LG15. 5. 29. c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} 20 HP. 12-G4. X.5770 Y5005 X.5007 X.5380 We have carried out the modification to the engine mounting, fixing the sandwich feet at the rear and the extra cross member in front, also the larger cross member in front of the radiator. Tests taken before and after the alteration shew that the jellying of the front of the car has been very considerably reduced, both comparisons being made with low tyre pressures. We consider that the engine vibration both forward and retard is now definitely worse than it was with the previous engine mounting. We have not yet a satisfactory explanation why 12-G4 was so bad as regards jellying because we have another car 14-G4 which has the identical frame and engine mounting as we previously had on 12-G4 and this car is wonderfully good for absance of frame jellying. Further tests are being made in connection with this. Hs.{Lord Ernest Hives - Chair} | ||