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 future engine for the Wraith and Bentley III, considering a Straight 8 engine as a replacement.
| Identifier | ExFiles\Box 97\1\ scan0051 | |
| Date | 22th May 1937 | |
| Sg.{Arthur F. Sidgreaves - MD} from Rm.{William Robotham - Chief Engineer} Hs.{Lord Ernest Hives - Chair} c. E.{Mr Elliott - Chief Engineer} We are not altogether happy about the future position of the Wraith and Bentley III with regard to an engine unit. We have been looking round for some way of getting a replacement unit for the Wraith moving with the minimum expenditure of effort by the Design and Development Depts. Recent investigations have indicated that, owing to the decision to carry the spare wheel at the side, the Straight 8 engine designed by E.{Mr Elliott - Chief Engineer} will not add more than 2" to the length of Bentley III chassis. It will drop straight into the Wraith frame when it has been lengthened to take the P.III engine. We think that the 8-cylinder engine which was designed for the Wraith has plenty of merit. It also is a safety first engine in that it is almost entirely conventional. We also consider that it can be made into a 300 cu. inch engine, either with an aluminium block, in which case a slight reduction in rubber gland size will be necessary, or, alternatively, as a cast iron block with wet liners. In either case, we should recommend a cast iron cylinder head. This will mean altering the drawings of the cylinder head. It would moreover be desirable to incorporate the Wraith type of tappet. Briefly, however, we do not think that any original design work would be needed to get this engine produced, but rather that it would be a case of adapting design improvements that have been incorporated on the Wraith 6 to the 8-cylinder unit. We have in mind that since there is nothing being done on the P.III engine, and the detailing of the 6-cylinder Wraith engine has been completed some little time ago, that this section in By's Dept. would be able to undertake the work on the Straight 8 engine unit. This could be fitted in while they are waiting for the design of the Phoenix unit, which is bound to take some little time to produce. The Straight 8 engine conforms with the requirements laid down that any replacement for the Wraith should be capable of taking a supercharger. Using the | ||