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).
Floorboard and dashboard insulation tests on a Bentley car to reduce engine noise and boom.
| Identifier | ExFiles\Box 138\1\ scan0117 | |
| Date | 21th February 1935 | |
| To Sg.{Arthur F. Sidgreaves - MD} & Wor.{Arthur Wormald - General Works Manager} From HE/Rn.{Mr Robinson} c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to Ex. c. to Bn.{W.O. Bentley / Mr Barrington} +634 Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson}9/KW. 21.2.35. Floorboard & Dashboard Insulation. We have now had the Bentley on the road with the dashboard and inside of the scuttle insulated on the lines of the Buick, the whole floor of the car including the inside of the luggage compartment covered with felt, and also particular care taken in the fitting to eliminate all air gaps. The car we chose was the worst Bentley that we have for general engine noise and boom. The results very largely parallel those obtained on the Buick; that is, engine noises such as those produced by tappets were practically eliminated from the inside of the car. Generally, over the whole speed range the alteration produced a much more desirable vehicle. The various bad booms in the car (the engine was not rubber mounted) were not eliminated, but were much reduced in intensity. Gearbox, axle and exhaust noises were not so noticeably affected as engine noises, perhaps reduced 40%. Summarising our conclusions, we believe that originally our Experimental car was considerably worse with regard to the fitting of the floorboards, the effectiveness of the mats, etc., than the sort of car which is sold to the customer. Therefore we anticipate that we have obtained a bigger improvement than can be expected on the average car that leaves the Coachbuilders. However, we are certain that there is considerable value in what has been done, particularly regarding the dashboard insulation. We recommend that after Bn.{W.O. Bentley / Mr Barrington} (and others who are interested) have run 2-E-IV car for a short time to obtain a value for the alteration which we have recently made to it, we should have the car back and insulate it as we have done our Experimental car. All the modifications have been carried out by our Derby Coachbuilders, so that after the modification, Bn{W.O. Bentley / Mr Barrington}'s car can be submitted to Park Wards or any other firm with a view to reproducing the improvements obtained. One feels that when the complete rubber engine mounting and isolated gear lever have dealt with vibrations, the additional elimination of noise by sound absorbing materials will be a great asset. Hs{Lord Ernest Hives - Chair}/Rn{Mr Robinson} | ||