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).
Experiments on the Goshawk 11 crankshaft friction damper to reduce engine noise and vibration.
| Identifier | ExFiles\Box 180\M1\1\ img061 | |
| Date | 15th September 1921 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to E.{Mr Elliott - Chief Engineer} c. to EY. c. to Da.{Bernard Day - Chassis Design} — c. to EP.{G. Eric Platford - Chief Quality Engineer} GOSHAWK 11. X4219 We have carried out several experiments with different adjustments of the friction damper on Goshawk 11. crankshaft. We found that if we increase the friction sufficient to overcome the period at 50 M.P.H. we introduce another period and considerable noise in the engine gear at lower speeds. The necessary friction to overcome the 50 M.P.H. period makes it impossible to move the friction damper, except by a long lever. The load on the springs is about 200 lbs. We are proposing to try a larger diameter flywheel on the front end. We recommend that an alternative scheme is got out using the friction flywheel as a separate unit to the spring drive as on the 40/50 H.P. We are certain that it will work and be reliable. We have tested Goshawk 1. on the road again. The engine is certainly much smoother than Goshawk 11. There is, however, a crankshaft period just over 50 M.P.H. It does not appear to be anything like as bad as the one on Goshawk 11. So far, one may be deceived because the tests were carried out on a chassis. We are making arrangements to fit an effective windscreen so that we can hear the noises better. Hs.{Lord Ernest Hives - Chair} | ||