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 to G. Cussons Ltd regarding difficulties with the Dalby Watson Optical Indicator.
| Identifier | ExFiles\Box 79\3\ scan0104 | |
| Date | 24th September 1918 | |
| Y/3181 EPC3/T24918. 24th Sept. 1918. Messrs. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Cussons, Ltd., Technical Works, Lower Broughton, Manchester. Dear Sirs, Re Dalby Watson Optical Indicator. We have the impression that the Dalby Watson Indicator, at least in its earlier form, was subject to the following difficulties:- 1. The apparatus had to be extremely close to the engine on account of the inertia of the air in the connecting pipe. 2. Owing to the close proximity of the pressure diaphragm to the engine cylinder and the free connection necessary, it was found that the diaphragm got very hot, and not only read incorrectly, but got softened and broke rather quickly. We understand, however, that Dr. Watson discovered that the vibrations in the pipe could be damped out by the use of a spiral of copper wire in the pipe. If this would permit of a reasonably long pipe between the engine cylinder and the diaphragm, we can understand the trouble with the diaphragms would be overcome. We shall be glad to know what modifications have been incorporated in the later form of instrument to overcome these particular points. Are you yet in a position to give us promise of delivery for this indicator? Yours faithfully, | ||