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).
Methods for mounting the car body to the chassis to reduce rolling and engine vibrations.
| Identifier | ExFiles\Box 14\8\ Scan234 | |
| Date | 15th March 1930 | |
| EVI/15.3.30 cont. in order to tie the body to the chassis to resistt rolling. It was thought that no engine or tyre vibrations would reach the body by this joint, the former being so far away thatthe vibrations would be damped out before reaching this point. The rear or auxillary support was inserted to take care of large cabriolet and landaulette heads when open, to prevent them bending the subframe and opening the doors. We have tried putting rubber at the centre support but on the short tests which we have been able to make we have been unable to appreciate in any way a reduction in the engine vibrations transmitted to the body. We quite see your desire to isolate the body as much as possible from the chassis, in order that the engine may be made solid (or nearly so)with the chassis. But, supposing we could do with a sub-frame mounted entirely on rubber, we do not think that would allow of a rigid mounting for the engine to add torsional stiffness to the frame, as the steering column, pedals and side levers would then transmit the engine vibrations. We believe that you tried this experiment some while ago, and reported that whilst it achieved much in the way of frame stiffness, freedom from highspeed wobble (as the front dampers were forced to work), and a stable steering, yet the engine periods could be felt on the column and pedals, and that the front wings vibrated at certain engine speeds. There is no doubt that we could devise a semi-flexible support at the centre in the place of the present solid one, but it it essential that all the normal load be taken at this centre support, and not at the rear. | ||