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).
Progress on improvements to the 25 HP Synchro-Mesh Gearbox, including noise reduction and testing of modifications.
| Identifier | ExFiles\Box 15\5\ Scan231 | |
| Date | 8th January 1932 | |
| To R.{Sir Henry Royce} (At Le CanadelHenry Royce's French residence). From Hs.{Lord Ernest Hives - Chair} c. to Sg.{Arthur F. Sidgreaves - MD} c. to Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to EV.{Ivan Evernden - coachwork} 310. Hs.{Lord Ernest Hives - Chair}6/MJ. 8.1.32. 25 HP. SYNCHRO-MESH GEARBOX. XS310. XJ310. It will be seen from the report on 18-G4. that the condition of the gearbox after 15,000 miles running is very good indeed. Considerable progress has been made in quietening the helical gears. The stage we have arrived at now is that the idling noise should be very little, if any worse, than the present standard box, and the third speed will be definitely much quieter. The improvement has chiefly come about due to burnishing the gears. That is, running them together with practically a polishing paste at the same time giving an axial motion so that the burnishing is distributed over the whole of the tooth. This treatment has been successful both on ground gears and gears which have been finally cut after carbonising, and which have not been ground. We are using the standard 14 pitch gears. The modified reverse scheme as on P.2. has proved satisfactory and is being adopted on all gearboxes of this type. We are expecting to test out tomorrow a modification to prevent the top gear having a tendency to work out, this being the one remaining criticism of this gearbox. It has been agreed to standardise the box and the Works have been instructed, in the meantime we are preparing another box built up with all the final modifications, for test. When this car arrives in France we can arrange that on its tests it goes to Le CanadelHenry Royce's French residence so that you can have an opportunity of judging the standard which we expect will be reproduced on production. Hs.{Lord Ernest Hives - Chair} | ||