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 A.T. Speedometer Co.Ltd. regarding discrepancies in speedometer test results.
| Identifier | ExFiles\Box 50\4\ Scan195 | |
| Date | 19th April 1928 | |
| X4308 c. Mailing. c. By {R.W. Bailey - Chief Engineer} /Cgh. {W Clough} EFC {E. Fowler Clarke - Electrical Engineer} 3/T. 19th April, 1928. Messrs. The A.T. Speedometer Co.Ltd., 20, Avonmore Road, West Kensington, London, W.14. Dear Sirs, 40/50 H.P. Speedometer. We are much obliged by your letter of the 18th inst. with reference to the tests which you have been carrying out on the above instruments, and have particularly noted your stated result that there is a fall of reading between 18 and 30°C. not exceeding 1.6%, whereas we have found 5%. We are carefully considering to what extent our measurement of temperature could possibly be wrong, but there is no doubt that it could not be wrong to the extent of the difference of 5% and 1.6%. In regard to the measurement of speed, no question arises in regard to this, because the speedometer is driven by a synchronous motor on the Derby Corporation Mains, which also drives a counter; the speed is therefore obtainable with a high degree of accuracy. We regret that it will not be possible to send you the two identical instruments of which we gave you the previous results, because these are probably gone out on production, but we will obtain one further instrument from recent deliveries and make a similar test. We will then have this instrument returned to you in accordance with your suggestion. At the same time we suggest that you should reciprocally make a particular test on one instrument which you would be about to deliver to us, and then deliver it marked specially for the attention of the undersigned, who will carry out a similar test on that instrument also. Ultimately we may then compare the results. Contd. | ||