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).
Short run of a 16 HP Riley to evaluate its overdrive gearbox.
| Identifier | ExFiles\Box 136\4\ scan0207 | |
| Date | 11th February 1938 | |
| To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c. Da.{Bernard Day - Chassis Design} c. Hdy.{William Hardy} 115/3 Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}1/MH.{M. Huckerby}11.2.38. OVERDRIVE GEARBOXES. We were able to have a short run on a 16 H.P. Riley. This is a 30 cwt. car with a four cylinder 2½ litre engine of 120 mm. stroke. The 3 speed cum epicyclic Warner gearbox, we happen to know costs £14 duty and carriage paid. It is used in America by Grahams. The overdrive ratio was barely audible even when listening for it at high speeds or pulled down to 15 m.p.h. When the box got hot a second or so was required for the upward change from direct to overdrive. The feature that when using the overdrive position of the control lever a free wheel was bound to operate in direct drive is in our opinion a great drawback to this arrangement. In the normal position of the control the car possessed an all helical 3 speed box. Using the direct ratio on which about 70 m.p.h. is obtainable Ticknall hill was climbed in 55-3/5 seconds. Rm{William Robotham - Chief Engineer}/Gry{Shadwell Grylls} | ||