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).
Investigation into Goshawk 11 engine vibration issues occurring at high RPM.
| Identifier | ExFiles\Box 74\3\ scan0248 | |
| Date | 2nd February 1922 | |
| To E.{Mr Elliott - Chief Engineer} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to Da.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to Wor.{Arthur Wormald - General Works Manager} X4221 Hsl/LG10.2.22. COSHAWK 11. ENGINE VIBRATION. X4221 With reference to the engine vibration which occurs at just over 3000 R.P.M. on the engine. We have obtained the following further particulars. It was noticed that when we ran the engine without the wheelcase fitted, beyond an engine speed of 3100 revs. the slipper wheel opened out, i.e., the two halves in the slipper wheel came apart, until the back portion actually rubbed on the cam wheel. We find that this occurred whether the engine was run light or at full throttle. Actually, whilst carrying out these tests we broke another cam wheel which proves the failure of the cam wheel is due to this vibration at high speeds. We have tried without the slipper wheels fitted but with the hub fitted to the crankshaft. Our impression is, except that we get distinct crisp crankshaft vibrations at lower speeds, the actual vibration is less at high speeds without the slipper wheel; the slipper wheel hub appeared to run truly. One can hear and feel that there is a period of vibration which comes on at 3100 R.P.M. - we are not able to get beyond it because of the valves leaving their seats. We have tried with a slipper wheel adjusted so that the wheels cannot fly apart. We have tightened the bolts and springs up choc-a-bloc and then released them 1/8 of a turn to make sure that the wheel is not solid. This appears to give the best results. We will send on a further report tomorrow giving more particulars. Hs.{Lord Ernest Hives - Chair} | ||