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 issues and proposed solutions for the 10,000 Mile Test Car 40/50 - 28-EX.
| Identifier | ExFiles\Box 11\5\ 05-page153 | |
| Date | 5th September 1934 | |
| x7941 To W.O.R. from E.{Mr Elliott - Chief Engineer} c. Hs.{Lord Ernest Hives - Chair} re 10,000 Mile Test Car - 40/50 - 28-EX. Referring to Sg.{Arthur F. Sidgreaves - MD}5/E.4.9.34, there is no weakening of the frame sides that we are aware of in the changes that have been made for flexible engine mounting. What has happened is that the mass of the engine is no longer rigidly anchored to the front of the car and this has resulted in altering the periodic effects, and there is loss of damping due to the frame no longer being steadied by the mass of the engine. We rather anticipated originally that we might not be able to go the whole hog on P.2. which is the conclusion we have already reached with regard to the Bentley chassis. On the Bentley we are only standardising the rear rubber mounting leaving the front end of the engine unit suspension as at present, and it seems to me we have got to do the same thing on the Phantom. I think we could convert 28-EX in France without bringing it back to the present rigid pivot mounting in front, and whether we take the torque on ferraplane rubbers or retain our present front feet for taking the torque could be decided by experiment. Another factor that has given trouble during the test is the breaking of the pedal shaft anchorage bolts. This pedal shaft locates the engine by means of a ball ended link, and it is very likely that the lateral oscillation of the nose of the engine relative to the frame which must be taking place at present is throwing heavy loads on this pedal shaft anchorage and causing the bolts to break. If we return as recommended to the rigid nose anchorage we think this failure would naturally be cured, but we can go further with this and dispense with the anchorage altogether relying on the front end, as we do now, to locate the unit endways and allowing the rear rubber mounting to take up the expansion due to temperature changes. | ||