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).
Interim report on experiments to resolve rattles in the latest type of gearboxes.
| Identifier | ExFiles\Box 99\4\ scan0221 | |
| Date | 23th June 1939 | |
| 428 To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c. Ds. c. Da{Bernard Day - Chassis Design}/Hdy.{William Hardy} c. By/CRL.{C. R. Lisson} Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}4/MH.{M. Huckerby}23.6.39. B.V. GEARBOXES. The following is an interim report on the position with regard to rattles in the latest type gearboxes. On 12.B.V, which has a 3½-litre 6-cylinder engine, there have been rattles about which a customer would complain, when getting away in first or second and when accelerating on overdrive up to 30 miles an hour. On this car we experimented with propellor shaft dampers. We started with the usual Rolls-Royce friction variety and tried various settings between 10 lbs.ins. and solid. In every case the rattles were worse and became increasingly bad as the load was raised. We next tried two dampers of the Studebaker variety, in which the inertia was driven by rubber cones. The first of these had no damping and the second had additional friction damping. Both types made the rattles worse. The one with damping caused rattles also in top gear. With any of the propellor shaft dampers fitted, rattles are also audible on the over-run, but to a much less extent than on the drive. The second series of experiments have been carried out on 11.B.V, which has an 8-cylinder engine. With the gearbox in its original condition there were terrible rattles up to 60 miles an hour on overdrive and direct, being worse at about 1500 engine r.p.m. To the gearbox in this car we fitted Hdy{William Hardy}'s anti-rattle device on all three cones. This has effected an enormous improvement in the gearbox and rattles are now only audible for a little distance on either side of 35 miles an hour on overdrive. The synchromesh change to overdrive has been spoilt and we have therefore asked Hdy.{William Hardy} to provide us with an anti-rattle arrangement which does not hold the cones in the central position with such force. | ||