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).
Road test report on car 34-EX evaluating noise levels after modifications, particularly tyre, exhaust, and transmission noise.
| Identifier | ExFiles\Box 96\3\ scan0037 | |
| Date | 10th January 1936 | |
| +360 Sg.{Arthur F. Sidgreaves - MD} e.{Mr Elliott - Chief Engineer} to Wor.{Arthur Wormald - General Works Manager} c. " Hs.{Lord Ernest Hives - Chair} re- 34-EX. Cx{Major Len W. Cox - Advertising Manager}4/KW10.1.36. I had an opportunity of trying this car last evening after Park Ward had finished inserting packing between the body and chassis as per W. instructions. The conditions, however, for the trial were very unfavourable in the sense that it was pouring with rain and the roads were very wet, but in order to not to delay the car coming to the Works I carried on. There is no doubt in my mind that a very considerable improvement has been effected, although it is clear that there is still room for further improvement. The tyre noise is by no means eliminated, but the extent to which it was previously experienced has been very greatly diminished. There are, I believe, three noises contributing to what one hears, and it is very difficult to isolate any one of them. The three I refer to are - exhaust, tyres and possibly transmission. There is a very definite 30 m.p.h. exhaust drone on 35-EX, and I am therefore presuming there is a certain amount of this in 34-EX. We managed to find a stretch of cobblestones in a Mews in Kensington over which we travelled at speeds up to 30 m.p.h., and I was agreeably surprised to find that there is no apparent increase in noise over the wood paving and tarred road surfaces that we had been traversing previously. Compared with what I experienced in Glasgow on this kind of cobble-stones this was a very great advance and a very encouraging result. I should think that the improvement was probably as much as 40 or 50%. The car is not as good in respect of absence of tyre noises above referred to as the V8 Cadillac which we tried in London yesterday.. That car I personally consider very silent in London. Cx.{Major Len W. Cox - Advertising Manager} | ||