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).
Summary of test results on torsional oscillations and vibrations at various engine speeds.
| Identifier | WestWitteringFiles\P\2July1926-September1926\ Scan137 | |
| Date | 4th September 1926 guessed | |
| contd :- -10- its alternating nature. At 1600 r.p.m. - and being a better diagram we are able to estimate this a little more accurately - the resulting deflection is approximately 1° 6' (0.33' each side of mean position) and equivalent to a static torque of 155 lbs/ft. The instrument used for these experiments is by no means perfect and even if such readings as the amplitude are not perfectly accurate it has served its purpose in indicating first the presence of the vibrations and secondly the frequency. All the above tests were of course conducted without any damping friction therefore the amplitudes shewn would be greater than with damping. SUMMARY OF TESTS WITH INDICATOR. (1) There are appreciable torsional oscillations at speeds of 3350, 1600, 1100 and 800 r.p.m. (2) The amplitude decreases in the order of the above speeds (3) The frequency of the vibration is between 9600 and 10050 oscillations per minute. (4) The amplitude at 1600 r.p.m. is approx. 1° 6' (.33' each side of mean position) and is equal to a static torque between the two ends of the crankshaft of 155 lbs.ft. At 3350 r.p.m. the amplitude is estimated to be 3° 49' (1° 54½' each side) with an equivalent static torque of 540 lbs.ft. This should be accepted with reserve due to the poorness of the diagram. (5) In service on the car the slipper damper seems to contd: | ||