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).
Trial of a De Normanville overdrive gearbox as a potential replacement for the Warner box.
| Identifier | ExFiles\Box 136\2\ scan0039 | |
| Date | 2nd February 1939 | |
| 1153 To Sg.{Arthur F. Sidgreaves - MD} from By.{R.W. Bailey - Chief Engineer} c. Hs.{Lord Ernest Hives - Chair} c. Rm.{William Robotham - Chief Engineer} c. Ox. W/S. By.1/MH.{M. Huckerby}2.2.39. OVERDRIVE GEARBOXES. Yesterday Hdy.{William Hardy}, Gry.{Shadwell Grylls}, and I tried an overdrive gearbox invented by De Normanville. Gry.{Shadwell Grylls} had by accident heard of its existence and had asked De N. to demonstrate it to us. It has been developed by Humbers but owing to financial disagreement De N. is no longer connected with them and is in a position to license his gearbox to anyone. The gearbox we tried was fitted to a Studebaker car. Changes from overdrive to direct or vice versa could be made at any speed at any throttle opening by the movement of a small knob. It was not necessary to touch the clutch pedal although the propeller shaft would have a better time if one declutched when changing up. At no time did the car free-wheel. This is such an advance on the Warner box we have obtained in that it has eliminated the two defects of the latter, namely, free-wheeling below 30 m.p.h. and the necessity for full throttle to change down, that I recommend it should be tried in preference to the Warner. We are looking into whether the overdrive unit will fit behind a Wraith or B.50 box. We understand from De N. that A.C.Wickman's of Coventry would manufacture a unit for test. Wickman is financially interested in the scheme and his standard of manufacture would be adequate. This would not mean work in our Tool Room. As the De. N. box represents what we have been looking for and as the development work has been done we shall go ahead and obtain a unit for test. By.{R.W. Bailey - Chief Engineer} | ||