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).
Bentley development regarding a lightened crankshaft, detailing vibration issues and flywheel loosening at high RPM.
| Identifier | ExFiles\Box 85\5\ scan0050 | |
| Date | 8th September 1933 | |
| X217. To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/CTS.{C. Trot Salt - Carburation} c. to By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/CTS.{C. Trot Salt - Carburation}10/KT. 8.9.33. BENTLEY DEVELOPMENT. LIGHTENED CRANKSHAFT LEC.3486. UNIT.B.5: Crankshaft Ex.11269. Balance weights Ex.11268. " " Ex.11278. Flywheel & Clutch LOP.GB.358. LeC.3418-3549. Mod. fixing of flywheel to crankflange LeC.3549. General Behaviour. Above 2500 R.P.M. and steadily increasing to 3700 R.P.M. flywheel fluttering becomes very marked and clearly visible. Vibration at 4500 R.P.M. caused the drive to come out of top gear, but the revs. were checked and no damage done. Running at this speed was most unpleasant. Difficulty was experienced to get the engine to maintain maximum power at 4250 R.P.M. but increased running at top speeds slightly improved this until a short endurance was maintained at 4250 R.P.M. full throttle, but on shutting down, the flywheel was loose on it's mounting. ------------ Half torsional period 2350 R.P.M. Critical period. 4400 R.P.M. Hs{Lord Ernest Hives - Chair}/C.T.Salt. | ||