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).
Performance of the Essex Terraplane straight 8 engine and comparing it to other engines.
| Identifier | ExFiles\Box 21\6\ Scan127 | |
| Date | 1st February 1934 | |
| X4217 See also File 5770 20/2/MP W/S. To Sg.{Arthur F. Sidgreaves - MD} from E.{Mr Elliott - Chief Engineer} E.8/HP.1.2.34. c. Wer. Hs.{Lord Ernest Hives - Chair} re Essex Terraplane. Replying to your memo Sg.{Arthur F. Sidgreaves - MD}7/E.31.1.34, I attach herewith copies of two memos E.3/HP.6.10.33 and E.1/HP.9.10.33 bearing on this subject. The second of these memos is a report giving my impressions of the Terraplane and my impression at the time was that the Essex engine is the most outstanding straight 8 I have ever driven. Previous examples of this type of engine of other makes have always given the impression of lack of smoothness on acceleration. There was never any doubt, of course, about smoothness on retard. The straight 8 is fundamentally smooth when the throttle is closed and the major critical vibration set up by the impulses alone which is mild enough to be dealt with by a crankshaft damper within the working range of the engine, therefore, dies away to nothing when the throttle is closed. On the other hand the 6 cylinder engine has a major critical vibration which cannot be tolerated within the working range of the engine even if enough damping could be made available to avoid engine failure and becomes even worse when the throttle is shut. The 6 cylinder engine becomes unpleasant under all conditions when the throttle is closed. With regard to the question of a replacement engine for the 20/25, you mention the straight 8, the 8 cylinder Vee, and the small 12. There is no doubt that the straight 8 would be a very satisfactory engine for its purpose, our only objection to it has been the increased length it demands under the bonnet, which with a conventional front end meant a longer wheelbase and that this was inconsistent with the policy we were adopting in connection with the SpectreCodename for Phantom III leading to a condition where the lengths of the bonnets of the large and small RR. models becoming too much the same and the small chassis being somewhat handicapped for weight, steering lock etc. If in the course of time we adopt a scheme | ||