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).
Comparison of the RR friction damper and the Summers Harmonic Balancer for reducing engine vibrations.
| Identifier | ExFiles\Box 25\3\ Scan243 | |
| Date | 22th April 1927 guessed | |
| contd :- -2- (1) The friction damper as already employed on RR. engines - and - (2) The Summers Harmonic Balancer as employed on the Buick, Oakland and other products of The General Motors. (This balancer we understand is similar in principle to the combined spring drive and damper on 1-G-1 engine. The chief condition necessary for the satisfactory application of either of these forms of damper is that the main resonant speed, or that vibration having the three cycles per revolution, must be outside the working speed range of the engine, as we have not known a case in our experience, and this is supported by the designer of the Summers Balancer, where either of these dampers of reasonable dimensions would deal satisfactorily with the 'master period'. We have experimental evidence to shew that if it were made to deal satisfactorily with the 'master period' - and it is evident it could be made to do so if sufficiently large - other vibrations would be introduced at speeds below this. Considering the RR. friction type of damper, we know that this is entirely successful in eliminating the vibrations due to the harmonics of the gas pressure torque and which vibrations were manifest on the Lorraine Dietrich. A standard RR. 20 HP. damper was also effective in damping out these vibrations on the Lorraine. The Summers Harmonic Balancer is in effect an inertia wheel flexibly connected with the end of the crankshaft having the flexibility and inertia so related that it opposes the natural swing of the crankshaft when under vibration. To state it briefly, the characteristic of a flexibly driven inertia contd :- | ||