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).
Resolving engine thudding and performance complaints for Chassis No. 34-EU, belonging to H.F. Thomas.
| Identifier | ExFiles\Box 47\1\ Scan281 | |
| Date | 4th May 1926 | |
| BJ. Copies to:- H.{Arthur M. Hanbury - Head Complaints} Hm.{Capt. W. Hallam - Head Repairs} EP.{G. Eric Platford - Chief Quality Engineer} [Handwritten initials] CWB1/IW/4.5.26. Re:- Chassis No. 34-EU. H.F.Thomas. ------------------------------------ In accordance with your wishes I called upon Mr. Thomas at Elstree this morning with regard to his complaints of the above car. I was accompanied by Shaw, one of Hm{Capt. W. Hallam - Head Repairs}'s staff at Derby, who I understand was in charge of the work on this car when it was sent to Derby and who tested it both before it was touched and after all work had been done on it. The facts of the case appear to be that the car was suffering from a bad thud in the engine and from a transmission groan. The transmission groan was cured by fitting a fabric coupling which has completely eliminated it, and need not be considered any further. In order to reduce the thudding to reasonable proportions it was found necessary to reduce the compression ratio considerably. Tests made before the car was touched on its receipt at Derby and after this alteration in the compression ratio show that there is no very material difference in its acceleration before and after the work was done. Further tests of acceleration made this morning by myself with Shaw and the driver of the car confirm these figures. From this information, from the feel of the car when driving, and particularly from two further runs which we made up Brockley Hill, I am of the opinion that this car is now a little below the average performance of its series, but that it is probably within the lowest permissible limits. I believe, if the car were placed on our dynamometer as it now stands that its power curve would be below the average, but above the lowest passable limit. Mr. Thomas was not at home and I understood would be in town somewhere for the rest of the week so that I was unable to see him, but as far as can be gathered his feelings on the matter are these:- That he had a car with a very good performance but thuddy, and he now has a car without the thuds, but of poor performance. He thinks he ought to have both the maximum performance and greatest possible smoothness together. I do not believe, however, that we shall achieve this result with the engine at present in the car. In fact it is only in very exceptional cases that it can be achieved at all. continued over | ||