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).
Issues with the gear change mechanism, including clutch braking, gearbox oil viscosity, and transmission slack.
| Identifier | ExFiles\Box 74\2\ scan0208 | |
| Date | 25th April 1921 | |
| To EP.{G. Eric Platford - Chief Quality Engineer} from R.{Sir Henry Royce} c. to CJ. c. to PN.{Mr Northey} c. to Hm.{Capt. W. Hallam - Head Repairs} c. to BY.{R.W. Bailey - Chief Engineer} c. to Hs.{Lord Ernest Hives - Chair} X3339 R16/G25.4.21. X.3427 RE CHANGING GEAR. X.3339. It has long been my impression that we often fit up our cars so that the clutch stops too quickly. This naturally comes about by our adjusting the clutch brake to act too effectively. It was always considered advisable to have the clutch brake spring of a high rating so that by pressing hard with the foot you could get extra action of the brake. I think it would be better, however, if we had a low rating spring ( so that the adjustment of the spring would be more regular) and a positive stop; the latter so that we can get plenty of friction by pushing the pedal a long way. I believe SA. was the only person who wished for the clutch to stop so quickly so that one can change quickly on a hill. I think, however, the disadvantage is so great in the hands of the ordinary driver that a free running clutch has much to be preferred to one that stops quickly. Two other points there are which have been bad for changing gear:- 1. The first is that we have recommended users to use thick oil in the gear box. This has been proved to increase the difficulties of changing gear and to cause an increase in the consumption of petrol, due to the lost work of turning up the thick oil. 2. The other point is that we are unnecessarily particular about a little torsional slack in the transmission and naturally without a little there is difficulty in getting the change gear to mesh, Contd.- | ||