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).
Investigation into the causes and potential solutions for noise originating in the rear seats of a vehicle.
| Identifier | ExFiles\Box 6\6\ 06-page209 | |
| Date | 4th April 1937 | |
| -2- NOISE IN THE REAR SEATS. This was agreed to be worse than the 25/30 on the original Wraith frame. The frame with heavier drilled side members produced a slight improvement, but it was not considered that this was sufficient. Tests indicated that the noise could be greatly reduced by alteration to the body mounting. It was found, however, that as the number of body mountings was reduced, so sideways shake in the rear seats was increased, and, therefore, this method of attack was abandoned. Our energies were next concentrated on finding out what could be done to the body to reduce noise, it having been established that a chassis which was satisfactory with close-coupled body was not satisfactory with a saloon. It was found that when certain modifications had been carried out, in particular to the floor boards, the back of the rear seat and the curvature of the roof over the rear passengers, a car could be vastly improved, in fact, in our opinion, the noise level would not be a subject of complaint. To check up whether the noise experienced was a function of this particular body or of the type, we removed the limousine from the chassis, and mounted a second limousine, which is an exactly similar type of body. The results corresponded with those obtained on the first body in every respect. The next step appears to be to come to some acceptable decision as to what can be done towards reproducing the conditions of coachwork which have been found to give us freedom from noise on experimental bodies. So far we have only run the heavy gauge frame with the drilled side members fitted with a box cross. We have a frame ready with the 'H' section cross to which a body will be fitted in due course. The improvement made to the back seat noise by frame changes has been so small that we are not optimistic that the 'H' section cross will produce much change. Furthermore, we consider it most inadvisable to reduce the rigidity of the frame any further. At the moment we consider that the frame is a fair compromise between freedom from noise and flexibility. A flexible frame on a bad road produces | ||