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).
Report comparing the noise levels of two heater models, S.2.C.A. and S.2.R.A., including tests with rubber mountings.
| Identifier | ExFiles\Box 137\2\ scan0130 | |
| Date | 11th August 1938 | |
| 1158. W/S. To Hn.{F. C. Honeyman - Retail orders} from Rm{William Robotham - Chief Engineer}/Std. Rm{William Robotham - Chief Engineer}/Std.5/MH.{M. Huckerby}11.8.38. Referring to your Hn{F. C. Honeyman - Retail orders}5/AH.5.8.38, we have now tested the heater which you returned to us (S.2.C.A. type) against the S.2.R.A. heater which we have here. When tested in the open by themselves the S.2.C.A. heater does not appear to be very much more noisier than the S.2.R.A. type provided that the full speed position of the switch is not used. However, when tested in the cabinet which you sent us, in the rear compartment of a division car, we agree that the S.2.C.A. heater is much noisier than the S.2.R.A. type and is not acceptable. In order to endeavour to quieten it we have tried mounting the S.2.C.A. heater on rubber in the cabinet in question, and find that this gives a marked improvement with regard to silence. Mounted in this manner the S.2.C.A. heater is comparable to the S.2.R.A. type for noise, again provided the full speed position of the switch is not used with the S.2.C.A. heater. The S.2.R.A. heater, if rubber mounted in a similar manner is again quieter, but does not seem to gain so much from this mounting as the S.2.C.A. type. The only difference between the heaters is the motor, and this seems to be the source of difference in noise. We have written Messrs. Clayton to settle whether the price difference (£1.0.0d.) is purely attributable to the motor, as if so this difference seems to be excessive. As soon as we get their reply we will acquaint you with the results. In the meantime we are sending back to you the cabinet with the S.2.C.A. heater rubber mounted as well as the S.2.R.A. heater separately, and we would like you to let us have your opinion on the relative noise as outlined above. If you consider that the S.2.C.A. heater rubber mounted in this manner is acceptable, then obviously it will be desirable to use it, if not, we see no alternative but to use the S.2.R.A. type at the higher price. When you have compared these heaters we would like you to return the one which you do not want to us. Rm{William Robotham - Chief Engineer}/Std. | ||