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 engine performance, focusing on vibrations, acceleration, and efficiency across different engine types.
| Identifier | WestWitteringFiles\R\2December1927-February1928\ Scan143 | |
| Date | 8th February 1928 guessed | |
| contd :- -2- approaching full throttle. We shall be very interested to compare the 20 HP. and 40/50 units with stiffened crankshafts, with this engine. Our general impression at present is that the 2.4.2. straight eight arrangement is in a very much better position than its equivalent 6 for the master period and incomparably better on the overrun for vibrations. We do not think there is any mystery about the absence of torque reaction on this car. The engine M.E.P. below 20 m.p.h. must be remarkably poor, as in spite of the low axle ratio the very low speed acceleration of this car is most disappointing, being much inferior to that of the Phantom. Additionally the kick from each firing stroke for equal M.E.P's could in any case be expected to be in propor- tion to the stk cyl. displacement and the Phantom is double that of the Stutz. We have never tried a car that could approach the Phantom for very low speed acceleration on a high gear ratio, all the eights and the double-six seem very disappointing at 20 m.p.h. and below when their displacement per ton mile is considered. The big cyl. certainly seems to bear out in practice its theoretically greater thermal efficiency. Attached are some notes on the balance of sixes, eights and twelves. Hs{Lord Ernest Hives - Chair}/W.A.Robotham. | ||