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).
Graph showing the performance of Phantom eddy current speedometers against instrument temperature for various axle ratios.
| Identifier | ExFiles\Box 50\4\ Scan183 | |
| Date | 20th March 1928 guessed | |
| INSTRUMENT READING AT 1000 RPM (MILES PER HOUR) INSTRUMENT TEMPERATURE (DEGREES CENTIGRADE) PERFORMANCE OF PHANTOM AT EDDY CURRENT SPEEDOMETERS A329 N730 15/52 B140 N488 14/52 16/52 AXLE 15/52 AXLE 14/52 AXLE N.B. The heights of the thin horizontal lines represent the correct reading for the three axle ratios specified thereon. | ||