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).
Report page detailing experiments on engine vibrations and the effects of damping friction on the 20 HP model.
| Identifier | ExFiles\Box 25\3\ Scan142 | |
| Date | 20th September 1926 guessed | |
| contd :- -4- (4) Vibrations due to the lower harmonics of the gas pressures are evident under load at about 1580 and 1105 r.p.m. and heavy damping friction intensifies them. (5) The amplitude of the vibration at the critical speed does not seem so large as on the 20 HP. This latter point we are investigating and hope to obtain further information when we have completed the apparatus for recording the vibrations. FURTHER EXPERIMENTS ON THE "20 HP". Similar tests to the above were made on the 20 HP. to determine the optimum value of the damping which could be employed with the standard slipper wheels. Exactly the same characteristics were evident with regard to the presence of the two high vibratory speeds with heavy damping friction as in the case of the Phantom. The following is a summary of these results :- (1) The normal amount of friction torque of 105 lbs.ins. did not seem to reduce the intensity of the vibration at 3300 r.p.m. to any appreciable extent. (2) A friction torque of 200 lbs.ins. was the max. that could be used before another vibration at 2450 r.p.m. became evident. (3) Friction torque higher than 200 to 300 lbs.ins. resulted in the vibrations being evident at both the higher and lower speed, but the higher one was not so violent as with the standard amount of friction. (4) Friction torque of approximately 1600 lbs;ins. resulted in the entire transference of the vibration to a speed of 2450 RPM. contd :- | ||