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).
Engine specification, comparing 4 versus 6 cylinders, for the 'Swallow' model.
| Identifier | WestWitteringFiles\H\January1922\ Scan26 | |
| Date | 8th January 1922 | |
| Handwritten at top: Setting on a Spec for the 2'nd line model '4' or 6 CYLS ? SWALLOW. Hs{Lord Ernest Hives - Chair} HAS A SAY ON TECH POLICY. To E.{Mr Elliott - Chief Engineer} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to Ds. c. to EY. c. to EP.{G. Eric Platford - Chief Quality Engineer} SPECIFICATION FOR "SWALLOW". We would suggest that it might be a good thing to try some of the 4-cylinder 11 HP. cars before we definitely decide on a 6-cylinder engine of so small a horse power. I have driven the 4-cylinder 10 HP. Humber, the 11.9 HP. Hillman and the 10 HP. Fiat. I did not feel on any of those cars that they would have been materially improved by addition of more cylinders. EP.{G. Eric Platford - Chief Quality Engineer} has had a long experience with a 10.6 HP. Humber Car - he does not consider it would be improved by having six cylinders. The 15.HP. Humber, I agree, did suffer from 4-cylinder vibration. We suggest that there must be a limit to the size when six cylinders show any positive advantage. We could make up a 4-cylinder engine of 11.9 HP. by using Goshawk 11. chassis and engine parts. We could fit a 4-cylinder crank and camshaft to an existing engine and reduce the cylinder bore in order to get the required capacity. We recommend that we obtain one of the best of the 10 or 11 HP. cars and try it before we definitely start on a 6-cylinder 11.9 HP. engine. We should then be able to satisfy ourselves that the 4 cylinder of that size does suffer from vibrations and that the extra cost and complications of six cylinders was necessary in order to get smoothness of running. Hs.{Lord Ernest Hives - Chair} | ||