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).
Preliminary report on a 15,000-mile test of the B.III chassis and engine components in France.
| Identifier | ExFiles\Box 97\4\ scan0126 | |
| Date | 7th November 1938 | |
| Hop b. SECRET. Sg.{Arthur F. Sidgreaves - MD} from Rm.{William Robotham - Chief Engineer} Hs.{Lord Ernest Hives - Chair} c. By.{R.W. Bailey - Chief Engineer} c. Da.{Bernard Day - Chassis Design} c. Mx.{John H Maddocks - Chief Proving Officer} PRELIMINARY 15,000 MILES' TEST B.III. 15,000 miles have now been completed on 8.B.V. in France. We are bringing the car back so that we can finalise our development work on this chassis with a view to releasing tools as soon as possible. It is necessary to do this because it is the only up-to-date B.III in existence. The main object of the test was to prove out the B.III pieces whose designs differ basically from anything we have done before. Those cover the new frame, the new front suspension, gearbox, semi-floating back axle with steel wheels, and entirely new braking system and cooling system. There have been no major failures on any of these features during the test, but a number of minor points have arisen which can easily be rectified and with which we are dealing. From the reports, it might be inferred that the engine has done very badly on this test. As a matter of fact, exception for compression ratio, carburation and camshaft, the Wraith and Bentley engines are now identical. In view of the fact that the Wraith engine completed its run so satisfactorily, we took the opportunity on this preliminary B.III run of trying out a number of less costly pieces, which included a soft crankshaft and strip bearings. These bearings have not done as well as we hoped, but they have done better than any other white metal bearings previously run on a Bentley in France, and would certainly have covered 20,000 miles without giving serious trouble. The overdrive, of course, is largely responsible for this. We think that the piston seizure was due to cracked valve seats. This engine was fitted with the head which we have discarded on the Wraith, because the new head was not available when the car left. A modified head followed it out, but the test was completed before it could be fitted. | ||