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).
Causes and prevention of resonant body booming noises in vehicles.
| Identifier | ExFiles\Box 137\4\ scan0242 | |
| Date | 6th March 1931 | |
| To R.{Sir Henry Royce} from Sg.{Arthur F. Sidgreaves - MD} re P.II. Booming of Bodies. Copy to Wsr. Hs.{Lord Ernest Hives - Chair} E.{Mr Elliott - Chief Engineer} RV. DA{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} PN.{Mr Northey} EP.{G. Eric Platford - Chief Quality Engineer} I have read your R1/M28.2.31 with considerable interest because at the present time so very much of our success and reputation is involved in the causes and prevention of the noises referred to. I fully appreciate the importance of everything possible being done to minimise the resonant characteristic of coachwork, and I am confident that our efforts in the last few years have been extraordinarily successful. Nevertheless I do not think that we can ever hope to eliminate entirely all resonant characteristics. I am very anxious that this question of body booms should not be allowed to act as a "red herring" across the trail of the real cause of the noises being produced, and I fear that in the past a good deal of valuable time and money have been lost by blaming most of the trouble on the body whereas we know from our own experience that, even when bodies conform with the very latest ideas in respect of damping of panels, roofs and floorboards, the objectionable features still remain. Also if a body does not cause resonance when first fitted, the moment any looseness or rattle appears in windows or doors these are immediately made prominent if engine vibrations are considerable. As an illustration of my point, I would refer to 58-GN, i.e. the car I have been using. All the technical officials concerned have agreed that this was an extremely unpleasant, noisy motor-car, due to engine "fuss", and this in spite of the fact that the type of body is one which we have learnt to know is most free from resonance and booming. It has an all-leather top etc. Another instance very vividly before us all recently has been that of Mr.Davies, who bought an exhibition P.II at Olympia. This car he returned to us as being non-acceptable owing to its booming characteristics at the 50/60 m.p.h. speeds, and it obviously should never have been passed as OK as it boomed at most speeds. | ||