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).
Diagnosing and curing engine vibrations in various car models, including the 25 HP.
| Identifier | ExFiles\Box 182\M19\ img117 | |
| Date | 9th February 1931 | |
| -3- mounting which allows the engine to move the dampers will be more effective, but we would need the inertia of the body to help. Torque reaction vibrations synchronise with the explosions. We believe the only complete cure for this is the twelve cylinder engine. 25 HP. Vibrations. With the more powerful 20 HP. and 'Japan' engine we found ourselves in trouble with vibrations at top road speeds. This bad vibration was caused by the propeller shaft whirling and the stiffer shaft has completely cured this. During these experiments we also separated out a vibration caused by flywheel wobble. It was proved that we could get through the flywheel wobble and at the higher engine speeds the engine ran smooth again but on the normal engine the flywheel wobble is about the maximum speed before the valves bounce. 18-G4. was sent to France with stiffer crankshaft, lighter flywheel and stiffer propeller shaft. As it was originally run with the Std. mounting GWH{George W. Hancock - Head Chateauroux}/hs.{Lord Ernest Hives - Chair} considered that although it was free from high speed vibrations due to the propeller shaft, it suffered from booms the same as the standard car. It was not until they altered the mounting that the reduction in booms could be appreciated at normal speeds. The last time I tried your car 16-GX. I was disappointed with it as regards the amount of boom. We should still be interested for you to confirm that you can get a car free from booms up to 65 m.p.h. If we can get a car free up to 65 m.p.h. we shall not get many customers complaining of what happens above that speed. It should be realised that it is more a question of noise than vibration which is complained of. Hs.{Lord Ernest Hives - Chair} | ||