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).
Test report on an A.T. Speedometer, noting its performance with temperature changes and a faulty trip counter.
| Identifier | ExFiles\Box 50\4\ Scan243 | |
| Date | 6th July 1928 | |
| To Roy. {Sir Henry Royce} from EFC. {E. Fowler Clarke - Electrical Engineer} c. BY. {R.W. Bailey - Chief Engineer} EY/Mtn. X.4388 EFC {E. Fowler Clarke - Electrical Engineer} 6/T6.7.28. B.563 A.T. SPEEDOMETER NO. B.563.800.14/52. WITH SMALL TYPE DIAL. We have now completed careful tests on this instrument and we find it very satisfactory in regard to the fall of reading with temperature. For instance, at 30°C. the reading is still slightly above the correct figure of 45 m.p.h. at 600 r.p.m. At 18°C. the reading is slightly above 46 m.p.h. The drop of reading between 18°C. and 30°C. therefore, is in the neighbourhood of 2%, but as stated by the makers, the instrument has been set so as always to have its error slightly high, which has not been the case with some previous instruments. In regard to the proportionality of the scale, this has been tried out and found to be reasonably satisfactory. There is, however, one fault with this instrument, viz. that the trip counter is not recording, the red figure oscillating between 0 and 1, so apparently it will again be necessary to return it to the makers. The instrument is returned herewith to EY. EFC. {E. Fowler Clarke - Electrical Engineer} | ||