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).
Noise insulation recommendations for Phantom III 25/30 and Bentley models for coachbuilders.
| Identifier | ExFiles\Box 138\1\ scan0279 | |
| Date | 2nd March 1937 | |
| 1160 To E/E V c. to C x. Rm{William Robotham - Chief Engineer}/FD.{Frank Dodd - Bodies}15/JH.2.3.37. NOISE INSULATION ON P.III 25/30 & BENTLEY. For the benifit of all coachbuilders we have had a mock-up made of a Bentley scuttle bolted to a standard dash-board, this is in sections and shows the method of fixing the felt to the body panels to meet up with the Seapak as supplied by R.R. The model has been photographed and prints should be given to all coachbuilders. The object of having this model made is to explain more clearly than the R.R. blue print does, the necessity of making a sound proof dashboard. Other points which should be made clear are, that the covering carpet should over lap the top edge of the front floor board by 2 inches, and that the edges of the carpet should also lip over the felt. Although the model was made for the Bentley exactly the same procedure should be carried out on the P.III and 25/30 H.P. With regard to the rest of the noise insulation scheme this seems to be fairly well carried out. Our recommendations were for a ½" to ⅝" felt mat rubber backed, to be fitted underneath the pile carpets. We also recommend that this felt together with the pile carpets should cover the pedal plates. In the majority of cases we have noticed that the pedal plate is left exposed. Where the body has a luggage boot, this should also be covered with a felt mat. We have found by experiment that much more can be done to imppove body silence by damping the body panels, roof etc. with Seapak, but this is fairly costly, and increases the weight figures. The question therefore of spending a lot of money on the body to obtain a very high degree of silence should be left between the customers and the coachbuilders. Rm{William Robotham - Chief Engineer}/F.Dodd. | ||