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).
Unfavorable comparison of post-war car horsepower and acceleration with pre-war models.
| Identifier | ExFiles\Box 77\3\ scan0191 | |
| Date | 10th September 1920 | |
| R.R. 235A (100 T) (S.H 159. 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 X3751a R.{Sir Henry Royce} from EP.{G. Eric Platford - Chief Quality Engineer} c. to Hs.{Lord Ernest Hives - Chair} C. to EFC. EP{G. Eric Platford - Chief Quality Engineer}2/F10.9.20. 10th Sept. 1920. X.3922. RE HP. AND WANT OF ACCELERATION. X.3751a. X.858. X.3056. With reference to your R1/G3.9.20, regarding want of acceleration on Mr. Hanbury's Trials Car, the question of the HP of our post-war car as judged by its performance on the road, compared with our pre-war car, is now receiving unfavourable criticism. In view of this, the following are points which we think you should be cognisant of :- 1. The improvement in HP of the post-war car, taking a general retrospect of the dynamometer records and performance on the road, commences from engine revs. 750 upwards, and the HP below this speed if anything is less than on the pre-war cars. 2. It is the customer who insists on holding on to the top gear at low engine speeds full throttle, who compares his post-war car as being worse for HP than the pre-war car, and it is certainly a fact that in making comparative tests of our post-war chassis with pre-war type chassis in for repair, such is confirmed. 3. In yours R1/G3.9.20, you specially point out the importance of obtaining tight compressions. This feature we are concerned about on our present pistons, and in this respect they do not compare favourably with pre-war. The difference is most probably due to construction only. We are now receiving and testing engines and cars with the extra two top rings fitted to the pistons, and from observations so far made, I feel quite safe in saying they are an improvement in this respect, although there are instances where such is not the case, and these we are investigating. Generally speaking, there is less noise of gases blowing past the pistons, distinctly audible at low speeds full throttle. The pressure and gas from the crankchamber are less and consequently less obnoxious fumes in the body. The crankchamber does not seem so hot on the test bed or dynamometer, and a better and more consistent torque is obtained at lower engine speeds. Contd. | ||