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).
Vehicle noise and vibration tests at various speeds and gears before and after clutch modification.
| Identifier | ExFiles\Box 137\4\ scan0048 | |
| Date | 1st November 1929 | |
| hs{Lord Ernest Hives - Chair}/Tsn5/ADS.11.29 contd. -6- all periods, noises etc. before and after removing the rear half of the flywheel and clutch parts. It was rather smoother than the average S.S. car; and in its standard condition it had the following list of periods :- Top Gear. Torque reaction periods at 13-16 and 18-21 m.p.h. and also a very slight one at 32 m.p.h. A slight boom was detectable at 40-46 on forward and over-run. Mild engine roar above 66 m.p.h. 3rd Gear. Roar at 32-35 and 40-43. Bad vibration at 48-55, forward and overrun. Smooth at 60 m.p.h. Vibrations above 60 m.p.h. and bad rattles at 65 m.p.h. The effect of removing the rear half of the clutch (comprising approx. 50% of the total inertia) was to lower all the periods previously noticed. Top Gear. Two distinct torque reaction periods at 11 & 15 m.p.h. very much more severe than before, so much so as to rattle the whole car. We could pick out a faint period at 40 m.p.h. The 66 m.p.h. noise had gone, and the car was definitely smoother up to 70 m.p.h. | ||