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).
Typed report on vehicle suspension dynamics, detailing axle velocity, damping tests, and natural frequency.
| Identifier | WestWitteringFiles\S\September1928-October1928\ Scan206 | |
| Date | 29th October 1928 guessed | |
| contd :- -5- The small numerals indicate the axle velocity in ft/sec. at the point marked. This is obtained from the slope of the line at that point, taking into account the horizontal scale of time which varies slightly from test to test, and the reduction in the linkage employed during the tests. The distance moved by the axle in inches may be obtained by multiplying the vertical distance moved by the pen in inches by the correct linkage ratio (e.g. X 5.34) The tests were carried out under extremes of damping, in some cases without any at all and in others with a setting as follows (when 'heavily damped'). Hydraulics 60 lbs. up and 30 lbs. down. Hartfords 60 lbs. both ways. The tests are intended to throw more light on the functioning required of the shock absorbers than on the feelings of the passengers. When running with no shock absorbers the dominant feature of the axles behaviour is its tendency to 'dance' at its natural frequency the whole time. This frequency is measured from these diagrams to be about 460 cycles per minute, and the motion is up and down in a vertical plane, and not criss-crossing. This dancing is not perceptible inside the car except by the pattering of the tyres on the road and the reduced grip when braking or cornering. The natural frequency of the car pitching on its springs as shewn at 45 m.p.h and after hump-back bridges with no dampers is 77.5 cycles per minute. Hs{Lord Ernest Hives - Chair}/An. | ||