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).
Proposed modifications for an A.T. Speedometer.
| Identifier | ExFiles\Box 165\4\ img271 | |
| Date | 14th February 1935 | |
| 16051. To Sg.{Arthur F. Sidgreaves - MD} From Hs{Lord Ernest Hives - Chair}/Wst. c. to Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to Gx. A.T. SPEEDOMETER. The modified speedometers which are proposed for production on R.R. and Bentley cars will have the following new features :- (a) Entirely re-designed magnet system. This is the direct outcome of a design which I submitted to Messrs. A.T. some time ago and which they have more or less successfully copied. The features of the new magnet system are greater magnetic forces, complete dynamic balance (our existing instruments have very bad periods of vibration) and non-interference with the magnetic systems of other instruments in the close vicinity. The magnet-system is also lighter due to the use of the new NI/FAL. magnet steel. (b) New Design of Frame and Worm Drive. (c) Larger Size (19 mm.) Total Mileage and Trip Discs. These will provide greater legibility of the figures. Regarding this last item we have been particularly unfortunate in being able to obtain from Messrs. A.T. a trip mileage recorder which did not fail on test when resetting the figures to zero. It was not until I paid a personal visit to their Works some time ago and made a suggestion regarding the tooth form of the ratchet on the discs that any serious effort was made on their part to get down to the trouble. As the result of my suggestion they have now produced new discs which should give every satisfaction. We think you will agree that the A.T. Co. have not distinguished themselves in developing this new instrument for us hence the inordinate delay, the final instruments only having been received three weeks ago. The fitting of the concave dials will make our instruments more expensive to produce but we feel that the improvement in construction and lighting is so definite as to be well worth the extra money. Hs{Lord Ernest Hives - Chair}/H.E.West. | ||