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).
Secret memorandum discussing criticism of stiff rear springs and proposing improvements for car suspension.
| Identifier | ExFiles\Box 72\3\ scan0022 | |
| Date | 12th July 1924 | |
| X.9410 To CJ. from R.{Sir Henry Royce} c. to BJ. RG.{Mr Rowledge} Wor.{Arthur Wormald - General Works Manager} HS.{Lord Ernest Hives - Chair} DA.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} PN.{Mr Northey} H.{Arthur M. Hanbury - Head Complaints} LP.{Mr Lappin} C. S E C R E T. R1/M12.7.24. E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. 11. RE. 46-PK. X.9410 Y8410 This car was criticised here on 11.7.24. by E.{Mr Elliott - Chief Engineer} DA{Bernard Day - Chassis Design} and R.{Sir Henry Royce} in the presence of HS.{Lord Ernest Hives - Chair} and HY.{Tom Haldenby - Plant Engineer} The chief subject was Sales criticism of front springing. At once the impression was that the chief and perhaps the only cause for complaint against the springing was that the rear springs were much too stiff and certainly had too much internal friction for slow speed with this light body. After many other tests and discussions upon work HS.{Lord Ernest Hives - Chair} and HY.{Tom Haldenby - Plant Engineer} left with the car for Derby, so that it could be made more like the car with which it was to be compared, and it was hoped to arrive at London some time on Monday. Since the front springing affects the passengers so very little, and for other reasons already explained, I am definitely of the opinion that the 25% increase in the stiffness of the front springs is a good compromise. The London Trials car which was compared with this speed model was not in a condition suitable for high speed anywhere especially in France, so that it is evident that the rear shock absorbers must be easily adjustable, unless we could use some graded, or one way shock dampers because for :- (1) Low speeds. Supple springs and slight damping are required. (2) Medium speeds. Less supple springs and more damping. (3) High speeds. Stiff springs and ample damping. The front springing is much less variable than the back because it has much more constant load i.e. more nearly the average load, and it affects the passengers very much less. It will bump if too supple, so that the difference of 10% would be hard to detect because other things would vary more. It was suggested that when there is any difficulty of springing, not only the flexibility should be carefully examined, but also the internal friction of the springs, which appear to vary much from amount of 'nip' and condition of surface and lubrication. Therefore :- (1) Examine tyre pressures and flexibility of walls. (2) Examine shock dampers. (3) Examine stiffness, and internal friction of road springs. especially the rear springs which are 4 times more important and likely to be the cause of the complaint. contd:- | ||