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 for an A.T. speedometer, showing readings at various temperatures.
| Identifier | ExFiles\Box 50\4\ Scan298 | |
| Date | 12th June 1929 | |
| X4308. Date 12-6-29 X.4308. A.T. SPEEDOMETER TEST. Speedometer No. C.727-740. 1/50 Speedometer type 20. H.P. A.T. Other particulars 80 MPH full scale Temperature (°C) Miles per hour indicated at 600 R.P.M. exactly. Revs. per mile of drive for correct speed reading. 22.0 49.8 723 24.0 49.7 724 26.0 49.4 728 28.0 49.2 732 30.0 49.1 733 32.0 48.9 736 35.0 48.7 739 Miles per hour at 1200 R.P.M. 3.6.29. EFC. {E. Fowler Clarke - Electrical Engineer} | ||