Test report detailing engine vibration, booming, and performance with and without balance weights.
| Identifier | ExFiles\Box 5a\1\ 01-page114 | |
| Date | 20th April 1931 guessed | |
| --3-- longer range. The periods on 3rd. gear are at 24 m.p.h. & 34 m.p.h. I could appreciate any improvement on the boom- ing of the car. The overrun vibration at 40 on top remains the same. Engine without balance weights but with slipper drive made standard. 7th. Test. There is very little difference between the engine with or without balance weights at normal revs, but on running the engine up to max. revs I found I could not reach the master period on 3rd. gear and at these revs the engine was very free from rattle and valve clatter. There are no periods on top gear outstanding until we get the boom period at 50 m.p.h. worse on retard at 48 m.p.h. Above that the engine is very smooth and the car fairly free from boom. On 3rd. gear the max. boom period is 34 m.p.h. On 2nd. " " " " 22 " In passing I feel the engine took longer to get to its max. revs without the balance weights than when they were fitted. The rattle and vibration we get on the overrun at 40 got definitely worse after a run of 40 miles when everything had got hot, and it was a hot day. The boom of the car on tram setts was much affected when I ran on to a patch that had just been watered to lay dust, the boom seemed to diminish about 15%. M.ayer. | ||
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).