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).
The difficulties encountered when experimentally fitting a Terraplane mounting to a Bentley car.
| Identifier | ExFiles\Box 86\5\ scan0112 | |
| Date | 14th May 1934 | |
| X 222 To Sg.{Arthur F. Sidgreaves - MD} from Ha/Ytn. Ha/Ru.3/KW.14.5.34. C. to Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} By.{R.W. Bailey - Chief Engineer} Dn. BH. EV.{Ivan Evernden - coachwork} Terraplane Mounting on the Bentley. We have fitted up the Terraplane mounting experimentally on the Bentley. We used the Streamlined car. The difficulties we encountered on the job were as follows :- (1) Clutch operation. We cantilevered the pedals to retain the existing linkage geometry of the Bentley. With this geometry, when the engine rotates the clutch goes in and out. With the more flexible engine mounting the movement was exaggerated and caused clutch jaggers. At the same time we think it has given us some valuable information in that it may account for some of the difficulties with standard Bentley clutch. We have overcome the difficulty in the way shown on the attached sketch, but a scheme is required. (2) Owing to the flexibility of the engine mounting, the standard floorboards are too close to the gearbox. On full torque the gearbox lid{A. J. Lidsey} rotates and rises appreciably. The metal floorboards which have been produced overcome the trouble and are now fitted to the car. (3) When a misfire occurs when idling, the engine shakes. This causes the pistons in the S.U. carburetters, which are just floating off their seats at slow running speeds, to rattle. We have overcome this by fitting throttle edge S.U's. The alternative is to fit S.U. pistons damped like those fitted to the new Rolls-Royce carburetter. We are trying this out. (4) Owing to the extra high compression engine fitted to this chassis, we were working under the worst conditions of torque reaction. In spite of the 10% higher gear ratio, at anything above 10 m.p.h. the engine was not bad for torque reaction. The worst feature was the headlamp brackets. These are really of inadequate rigidity and require attention on all Bentleys. Part of the movement comes from the lamp standard itself and part from the flexibility of the frame at the point at which the lamp brackets are attached. | ||