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).
Advantages and disadvantages of a narrow-angle V8 engine design.
| Identifier | ExFiles\Box 4\1\ 01-page024 | |
| Date | 15th December 1933 | |
| To E.{Mr Elliott - Chief Engineer} From Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}9/KT.15.12.33. NARROW ANGLE V.8 ENGINE. In "Automotive Industries" of Dec.2nd 1933, P.M. Heldt puts forward a suggestion of a V.8 engine of 20° between cylinder blocks incorporating an unusual spacing of the crank throws to obtain dynamic balance. The outstanding advantages of this engine are that it is shorter than an "in line" engine, a less awkward shape than a 90° Vee, and has no top torsional period. The half period is of less severity than the straight 8 engine. As regards dynamic balance the engine is not as good as a 6 cylinder. There are no secondary forces or couples, and the primary force is balanceable by a counter-weight, but there is, however, a primary piston couple. The crankshaft itself is out of balance but can be corrected by suitable counter-weights. A two per rev inertia torque of considerable magnitude is present. Though this will not cause an overrun torsional vibration in the running range, it may cause over-run roughness and booms as in the 6 cylinder engine. The length of the engine judging by the Lancia De Lambda is about .66 that of the straight 8 but necessitates long connecting rods. We doubt whether the unusual crank arrangement would give a better engine than the Lancia whose demerits might be stated to be those of a 4 cylinder, but to a much lesser degree. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} | ||