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).
Test report on fitting Ferodo interleaving material to springs on 1.EX Car and its effect on axle dither.
| Identifier | ExFiles\Box 78\2\ scan0319 | |
| Date | 7th September 1920 | |
| R.R. 235A (100 T) (S. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 643, 19-2-20) G 2618 X3461b To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to Dn. c. to Da.{Bernard Day - Chassis Design} c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to PN.{Mr Northey} Hsl/LG7.9.20. X.3763. 1.EX CAR. X.2628. X.3483. X.3981. X.3461b. We have fitted Ferodo interleaving material to all four springs on 1.EX Car. We tested the car with this material fitted and found that it had a most marked effect as regards causing the back axle to dither on the road. Mr. Northey has used this car and although he did not know that the interleaving material was much worse than standard cars. The axle dithered when the car was coasted and if the foot brake was applied, it was also very bad. During these tests the car was fitted with rear shock absorbers. We found the only way we could reduce the tendency for the axle to bounce was to fit up the rear shock absorbers so that the maximum friction was on them from the first stage. The shock absorbers as they are now on 1.EX Car give a friction of 60 lbs. throughout the whole range. So far we have had no signs of the springs squeaking since we have fitted this material. We found we could also improve the back axle dithering even with the normal shock absorbers if we reduced the tyre pressures. We are now measuring the actual friction in our rear springs. Contd. | ||