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).
Letter from a supplier discussing dimensional discrepancies of a returned bellows unit and suggesting a material change for rebuilding.
| Identifier | ExFiles\Box 156\2\ scan0047 | |
| Date | 28th March 1938 guessed | |
| Page 2 Messrs. Rolls-Royce Ltd. by measurement since you returned the unit, is 1.259" and if you add to this .323" which you state was the movement from the cold stop to the free position, it gives a free length of 1.582". On the first page of your letter you state that the overall length is 1.600" while we by measurement find it to be 1.640" on one side and 1.675" on the other as the bellows was slightly bent, the average of which is 1.657". The 1.600" mentioned in your letter does not compare with our figure of 1.437" as this latter dimension was bellows only without plates, and when the thickness of the plates is added it would read 1.695". Apart altogether from the dimensions mentioned in our various letters it appears that the free length of the bellows has dropped from 1.695" to 1.657" during your trials, that is, .038". It would seem, therefore, that the pressure within the water system is either greater than the test pressure which we applied or alternatively the combination of pressure and temperature existing in the engine causes a set in the bellows. The only thing that we can suggest is that the bellows should be made of "Alumbro" instead of 80/20 brass as this material has a higher tensile strength and is less subject to fatigue. We are, therefore, rebuilding the unit with a bellows of this material and will return it to you on Wednesday this week. Yours truly, THE BRITISH THERMOSTAT CO.LTD. W.Martin Hurst. Director. | ||