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 with a small type dial, detailing reading variations and temperature effects.
| Identifier | ExFiles\Box 50\4\ Scan252 | |
| Date | 2nd October 1928 | |
| To BY. {R.W. Bailey - Chief Engineer} from EFC. {E. Fowler Clarke - Electrical Engineer} c. BY {R.W. Bailey - Chief Engineer} /Mtn. c. Hs {Lord Ernest Hives - Chair} /ATL. XL3056 EFC {E. Fowler Clarke - Electrical Engineer} 2/T2.10.28. A.T. SPEEDOMETER NO. B.9|9.742.15/52. with SMALL TYPE DIAL. We have now concluded variation of reading tests of the 15/52 instrument with small type dial recently obtained. We find that this instrument reads correct, i.e. 48.2 m.p.h. at 600 r.p.m. at a temperature slightly above 29°C. Further, we find the fall of reading between 18°C. and 30°C. to be 4½% which is rather higher than the fall in the case of the previous instrument, as reported in our EFC {E. Fowler Clarke - Electrical Engineer} 6/T6.7.28, but nevertheless is just within our required limit. We are now handing this over to be placed on expl. chassis 12-EX for a 10,000 mile test (after which the instrument will be re-tested to ascertain if any change of reading has occurred). EFC. {E. Fowler Clarke - Electrical Engineer} | ||