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).
Design history and performance of the auto friction damper on the 40/50 model.
| Identifier | ExFiles\Box 181\M9\ img044 | |
| Date | 24th August 1931 | |
| To E.{Mr Elliott - Chief Engineer} From Hs.{Lord Ernest Hives - Chair} Hs.{Lord Ernest Hives - Chair}12/MJ.24.8.31. y634: AUTO FRICTION DAMPER. ON THE 40/50. You will remember at the time when this was designed the demand for it chiefly came about because of the "bus knocks" which were audible at low speeds if the present damper for any reason got a slight excess of friction load. At that time we were not using balance weights and we were not running fast enough to get anywhere near main torsional periods. The only crankshaft period the damper was expected to deal with was the half torsional. At the time when we were working on this, we came to the following conclusions. We found if we arranged the centrifugal weights so that they gave sufficient poundage to deal with the half torsional period, that the engine became rough at the higher speeds when the load on the damper was increased approximately four times. We came to the conclusion that the damper was working practically solid and that there had to be a very considerable crankshaft distortion before it could work. We are, however, arranging to repeat some of these tests because, as we poit out, this type of damper has never been tested to see its effectiveness on the main torsional period. Hs.{Lord Ernest Hives - Chair} | ||