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 on a 4 1/2 litre Bentley.
| Identifier | ExFiles\Box 138\1\ scan0243 | |
| Date | 21th March 1936 | |
| x1160 F.{Mr Friese} DODD. file Shean Go from E.{Mr Elliott - Chief Engineer} P Rm{William Robotham - Chief Engineer} C. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} Hs.{Lord Ernest Hives - Chair} By.{R.W. Bailey - Chief Engineer} E.5/HP.21.3.36. re Noise Insulation on 4 1/2 litre Bentley. Replying to your memo C.1/MK.20.3.36, first of all this confirms that we agree to the scheme referred to in Hs{Lord Ernest Hives - Chair}/FD.{Frank Dodd - Bodies}3/KW.18.3.36 to be used pro-tem. This scheme utilises three layers of 1/2" felt covered with a layer of black fibre secured by split pins and washers to the dash. The felt which is of a very soft and floppy material requires the fibre board to hold it in position and put it under compression, the three 1/2" layers being reduced to 1" finally, when assembled. For various reasons we do not favour this as a permanent scheme, and in the meantime we have been working on the use of an insulator made up of layers of Seapak sewn together to the required shape. This material has the advantage of being stiffer and does not require initial compression, so that it is only necessary to cover it with a carpet to complete the job. We are using six layers of Seapak, aggregating the thickness of 1", and where the insulator is fitted round the steering column bracket the various layers can be cut as required to form a neat fit to the sloping shape of the bracket. The Seapak is made to completely cover in the dashboard rear face right down to the top edge of the floorboards, and except opposite the pedal plate passes below and is trapped by the floorboards. For holding the insulation in position we propose to use some form of stud with a spring clip fastening. These studs would of course have to be long enough to allow for the 1" thickness of insulation plus the carpet. Approximately four spring clips will be required top and bottom, the lower ones being re-enforced where they hold the carpet against the vertical portion of the dash on Phantom III, or the sloping portion as on Bentley, by a long strip of steel sewn in to the carpet. We may also use similar strips for the four fasteners at the top of the carpet if found necessary, but the intention | ||