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).
Comparison of crankshaft and engine designs, including those of Chrysler, Stutz, and Alfa-Romeo.
| Identifier | WestWitteringFiles\T\November1928\ Scan122 | |
| Date | 13th November 1928 guessed | |
| contd :- -7- counter weights as to be independent of bearing support for its truth of running at high speeds. We prefer this to the American scheme of putting the weight into a cast iron crankcase. We think that from the point of view of the bearings alone, it should be possible in an engine with small cyls. in proportion to the size of the crankshaft to make the crankshaft so smooth running at high speeds that the main bearings could be flexibly mounted, to reduce the loads on them, or nearly all omitted. In practice there might be whirling troubles. OTHER CARS. Of other cars that we have tried, the Chrysler-72 which has both xx counter weights and a cast iron crankcase, was very smooth indeed, particularly noticeable on the overrun. The Stutz had a large cast iron crankcase, and a heavy crankshaft without balance weights. It had cyls. the same size as the 20 HP. and a solid engine mounting. It was very smooth up to about 3600 r.p.m; or more. We do not think that the addition of two more cyls. to the 20 HP. would attain this object i.e., it is not all essentially due to the straight-8 arrangement. Another interesting car which we have tried recently is the 1 1/2 litre 6-cyl. Alfa-Romeo. The one we tried was not S/C. This car has counter weights and an aluminium crankcase and plain bearings but we do not know how the counter weights or bearings are arranged. It runs up to over 5000 r.p.m. and would be dead smooth but for the fact that no crankshaft damper is fitted. The result is that the engine emits a buzz as each period is passed through in turn, but is very smooth indeed in between. contd:- | ||