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).
Performance graph for a Phantom's eddy current speedometer, plotting instrument reading against temperature for various axle ratios.
| Identifier | ExFiles\Box 50\4\ Scan189 | |
| Date | 24th May 1928 | |
| INSTRUMENT READING AT 600 RPM (MILES PER HOUR) INSTRUMENT TEMPERATURE (DEGREES CENTIGRADE) PERFORMANCE OF PHANTOM AT EDDY CURRENT SPEEDOMETERS INSTRUMENT B.138. N 730. 15/52 16/52 AXLE Correct reading for 15/52 axle with special gear box drive as on 12 EX. 15/52 AXLE 48.9 Every observed point in contact with line. 14/52 AXLE N.B. The heights of the three horizontal lines represent the correct reading for the three axle ratios specified thereon. | ||