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).
Suspension issue causing rear passenger discomfort over bumps in the Spectre model.
Identifier | ExFiles\Box 95\3\ scan0059 | |
Date | 31th January 1935 | |
To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Les.{Ivan A. Leslie} c. to Wor.{Arthur Wormald - General Works Manager} c. to By.{R.W. Bailey - Chief Engineer} SpectreCodename for Phantom III Suspension. Throw up at the Rear on a Bump. The phenomenon is far more pronounced on cars having independent suspension. The unpleasant sensation experienced from the rear seats is in the form of a sudden upward acceleration just after the rear wheels have passed the crown of the bump, throwing the rear passengers off the seats towards the roof of the car. The effect is amplified with independent suspension cars, where the initial spring deflections are similar front and rear. On a Phantom II where the front springs are twice as stiff, the bounce of the front of the car towards its bump buffers takes place before the impulse is received at the rear. On independent suspension cars the front reaches the bump buffers at the same time as the rear reaches full rebound. We are procuring springs so that we can try Ph.II initial spring deflection on SpectreCodename for Phantom III and SpectreCodename for Phantom III initial spring deflection on Ph.II. The severeness of the shock received is very largely affected by the proximity of the rear seats to the rear axle. The shock received when sitting on SpectreCodename for Phantom III occasional seats is practically unnoticeable, so that moving the rear seat forward or the rear axle back should be a great advantage. The Cadillac, with its rear seat 8" further forward relative to the rear axle than SpectreCodename for Phantom III, suffers with this same complaint. The discomfort, although not as bad as SpectreCodename for Phantom III, is distinctly inferior to a Ph.II with an overhanging body. We are sure the degree of discomfort in the Cadillac would not be accepted by R.R. customers. After observations aided by using a slow motion cinema camera, we have been able to examine the functioning of the car more closely. With all independent suspension cars the front wheels leave the road, whereas those of Continental sprung cars do not. This is due to the smaller amount of rebound movement. A Ph.II has over 4" rebound movement, whereas SpectreCodename for Phantom III has only 2" before the buffers. It has been observed on some cars that the front wheels are put back on to the road by the impulse from the rear. | ||