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).
Table of engine revolutions at various road speeds for different axle types, with a secondary table for Goshawk 11 gear reduction ratios.
| Identifier | ExFiles\Box 75\1\ scan0271 | |
| Date | 4th May 1923 | |
| X4247 4.5.23. EFFECTIVE TYRE DIA. 31.4" WHEEL MAKES 642.6 REVS. PER MILE. ENGINE REVS | Road speed. M.P.H. | 13 tooth-axle | | | 14-tooth axle. | | | 15th-tooth axle. | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | Top. | 2nd. | 1st. | Top. | 2nd. | 1st. | Top. | 2nd. | 1st. | | 5 | 246 | 406 | 780 | 228 | 374 | 722 | 213 | 348 | 676 | | 10 | 492 | 812 | 1560 | 456 | 746 | 1442 | 426 | 696 | 1350 | | 15 | 740 | 1218 | 2350 | 687 | 1123 | 2170 | 641 | 1048 | 2035 | | 20 | 985 | 1610 | 3125 | 913 | 1498 | 2900 | 852 | 1394 | 2700 | | 25 | 1230 | 2010 | | 1142 | 1872 | | 1045 | 1715 | 3240 | | 30 | 1480 | 2430 | | 1373 | 2240 | | 1281 | 1985 | | | 35 | 1723 | 2830 | | 1600 | 2618 | | 1492 | 2440 | | | 40 | 1970 | 3240 | | 1830 | 2990 | | 1609 | 2630 | | | 45 | 2218 | | | 2058 | | | 1918 | | | | 50 | 2463 | | | 2287 | | | 2135 | | | These results are computed on the slide rule and should not be taken as exact. Speeds on Lower Gears for Goshawk 11 Ratios. | Speed | Reduction 13-tooth | Reduction 14-tooth | Reduction 15-tooth | | --- | --- | --- | --- | | 3rd. | 4.615 - 1 | 4.285 - 1 | 4 - 1 | | 2nd. | 7.52 - 1 | 7.008 - 1 | 6.53 - 1 | | 1st. | 14.615 - 1 | 13.6 - 1 | 12.7 - 1 | Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||