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).
Design considerations for the P.III. Series II model, comparing it with the Wraith and Bentley III.
| Identifier | ExFiles\Box 91\1\ scan0515 | |
| Date | 20th August 1937 | |
| To By.{R.W. Bailey - Chief Engineer} from Rm.{William Robotham - Chief Engineer} c. to Sg.{Arthur F. Sidgreaves - MD} c. to Hs.{Lord Ernest Hives - Chair} c. to Da.{Bernard Day - Chassis Design} c. to Mx.{John H Maddocks - Chief Proving Officer} P.III. SERIES II. It was originally suggested that the P.III.2. was to be the Wraith frame and front suspension adapted to take either a 25/30 or 40/50 engine. Since analysing the number of pieces in the Wraith front suspension, however, we believe it would be wrong to perpetuate this design. Furthermore, we have had quotations for Bentley III. frames which shew a price about half the Wraith figure. Therefore, it does not seem to be sound policy to perpetuate the Wraith frame. In view of these facts, we believe that we should not proceed with the design of these parts for the P.III. until we have run Bentley III. and assimilated lessons to be learned therefrom with regard to handling, durability, simplicity and manufacturing costs. Meanwhile we have plenty of work on Phoenix to keep us occupied. Apart from the frame and front suspension, there are quite a number of features on P.III.2. where we know what to draw, if the specification is agreed on, and it is well to have these features in mind when common parts are being designed - (1) P.III. engine to go in the same frame as the 25/30. (2) Universal gearbox fitted to the P.III. engine. This has already been adapted for central change. (3) The engine unit to have all the cost taken out of it that is possible without reducing its efficiency. Personally, we think that dual ignition is completely out of date, as also are two plugs per cylinder. Two plugs per cylinder are responsible for putting up the heat to the radiator 15%. continued | ||