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).
Arguing against making the Bentley III flywheel and clutch identical with the Wraith III, recommending the retention of the standard 10' clutch.
| Identifier | ExFiles\Box 99\1\ scan0075 | |
| Date | 21th April 1937 | |
| 2006 412 Da.{Bernard Day - Chassis Design} from Rm{William Robotham - Chief Engineer}/Smth. c. Hs.{Lord Ernest Hives - Chair} c. By.{R.W. Bailey - Chief Engineer} c. E/Hdy.{William Hardy} Rm{William Robotham - Chief Engineer}/Smth8/R.21.4.37. BENTLEY III - FLYWHEEL & CLUTCH. Re: E/Lid.{A. J. Lidsey}1/HP.9.4.37. We do not agree to the proposal to make Bentley III flywheel and clutch identical with Wraith III. In our opinion, the present standard 10" clutch should be retained for the following reasons:- (1) Its inertia is only about half of that of the 11" model. (2) It costs 9/- less. (3) We have run an 11" clutch on 6.B.IV in a 10,000 miles test and got bad lug wear. Presumably this is due to the large inertia of the pressure ring, and also to the large total inertia lowering the torsional crank-shaft period. We use the 11" clutch on 25/30 and Wraith because considerations (1) and (3) are not of importance, and because of the lower pedal pressure and increased area of facings which the larger model gives us. To fit the smaller clutch the inner diameter of the flywheel friction surface, and the p.c.d. of the fixing studs will have to be reduced. Rm{William Robotham - Chief Engineer}/Smth. | ||