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).
Secret memo detailing the test results and issues found with an EAC.11 engine.
| Identifier | ExFiles\Box 69\2\ scan0173 | |
| Date | 24th October 1924 | |
| 48770 PN{Mr Northey}1/DN24.10.24. FROM PN.{Mr Northey} To CJ. S E C R E T. 48770 Yesterday at Gerrards Cross I tested with Hs.{Lord Ernest Hives - Chair} an EAC.11. After our run I was informed that the compression of this engine was higher than normal as R.{Sir Henry Royce} wished to test an engine in which the compression had been raised. Consequently the impression I gained would probably be quite unfair as a measure of the merits of an EAC. engine having a lower compression. I found that the general power and acceleration were extremely vigorous, but that the roughness of the engine's running was altogether undersible and altogether greater even than in the case of 11-AU, which is our new 40/50 HP. demonstration Open Touring car, which I will return into the Works on Monday to have this very feature dealt with. I noticed that in picking up from quite low speeds, such as 7 - 10 m.p.h., there was a sudden access of roughness and vibration of a remarkable character. Hs.{Lord Ernest Hives - Chair} explained that this was owing to the fact that the throttle at that point opened quite a large amount suddenly. Therefore this conditions would not arise if the design of throttle was modified to suit. I found the slow running of this engine when the chassis was either stationary or moving slowly, no better than a badly adjusted 40/50 HP., with both ignitions on. I found that the exhaust noises which we are complaining about in connection with the new 40/50 HP. design, were at least as bad as in the case of 11-AU quoted above. There was no throttle governor on this engine and the governing of the ignitions is not the arrangement which will be ultimately fitted. The front wheel brakes were fitted with the radius rod controlled to the axle; although the design is not in any way final, I looked upon this as being a very important modification which enables us to consider the springs of the chassis from one point of view only, that is, general riding comfort. From the point of view of general accessibility, it was not easy to form an opinion of the various parts under the bonnet, in view of the fact that the arrangement was not in any way final. I fear, however, that the position of th contd :- | ||