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).
The chassis gear ratios, engine revs, and dynamo revs for the Goshawk II and III models.
| Identifier | ExFiles\Box 6\4\ 04-page165 | |
| Date | 1st May 1926 | |
| X5312 1.5.26. GOSHAWK II & III. CHASSIS GEAR RATIOS, etc. The two back axle ratios are now :- 11/50 12/50 giving ratios of :- 1 : 4.545 1 : 4.167 Taking the low back axle ratio, namely, 1 : 4.545, the miles per hour at 1000 r.p.m. of the engine are :- Goshawk II. Goshawk III. Reverse 4.8 } These correspond { Reverse 6.4 1st. 6.5 } to an effective tyre { 1st. 5.5 2nd. 12.6 } dia. of 31.4". { 2nd. 8.5 3rd. 20.6 } (exact 20.56). { 3rd. 13.55 { 4th. 20.6 With the same low axle ratio, the following table gives the engine revs. and dynamo revs. for various speeds in miles per hour :- M.P.H. Gos.III Gos.II Gos.III Gos.II Gos.III Gos.II Gos.II&III Dynamo 1st. 1st. 2nd. 2nd. 3rd. 3rd. 4th. revs.on top gear 10 1820 1545 1136 793 739 487 730 12 2180 1850 1364 950 886 584 876 15 2730 2315 1705 1189 1106 730 1095 20 - 3090 2272 1585 1475 973 1460 25 - - 2845 1984 1847 1217 1825 30 - - - 2380 2215 1460 2190 40 - - - 3170 2950 1945 2919 50 - - - - - 2433 3649 KPC. | ||