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).
Views on crankshaft design, engine vibrations, and the use of balance weights for 6-cylinder engines.
| Identifier | ExFiles\Box 25\3\ Scan377 | |
| Date | 9th January 1929 | |
| To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Tsn. X634 Hs{Lord Ernest Hives - Chair}/Tsnl/LG2 9.1.29. CRANKSHAFTS. In accordance with our brief conversation when you were up recently, I am sending you my latest views on the above subject. You may remember that I suggested in a report recently that we should find the origin of much of our high speed engine fuss in the crankcase and crankshaft, and indicated ways in which this tendency might be reduced, e.g. by stiffer and heavier engines and the use of balance weights. I have come to think since that pure weight in the crankshaft, merely as weight, is a desirable feature. I gave reasons why I disregard out-of-balance and torsional vibrations as two necessary and irreducible evils causing engine vibration. I think they can be entirely forgotten. The excellence of the 6-cyl. engine lies in the fact that the dynamic forces very nearly balance out for the whole engine. Nevertheless, for individual cylinders they can be very large, and the inertia torque combines for some cranks to still higher figures. I believe that owing to these forces being so big (+ one or two tons) and vibratory in nature (alternating 50 or 60 times a second), and also owing to the elasticity of materials of engine construction, their effects on the engine parts are to produce a constant series of small vibratory contd:- | ||