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).
Diagnosis of booming and vibration issues by swapping chassis and bodies between different cars.
| Identifier | ExFiles\Box 137\4\ scan0243 | |
| Date | 6th March 1931 | |
| To R.{Sir Henry Royce} from Sg.{Arthur F. Sidgreaves - MD} The roof certainly was of metal but it was fitted with a patent damping springing device which has been very successful in eliminating booming. W. had this car in their hands and finally gave up any further attempt to cure the trouble as hopeless, even after trying the modified engine suspension which effected considerable improvement on 58-GN. Meanwhile the same coachbuilders had on hand an exact duplicate of Mr.Davies's car with the same sort of roof etc. PN{Mr Northey} tested this car to make a comparison with Mr.Davies's and he found that it was free from the disturbing booming complained of. It was offered to Mr.Davies and, whilst agreeing the improvement, he would not have it as he wanted his special exhibition body. Our only course, therefore, was to risk a changeover of the two chassis with the result that PN{Mr Northey} found on test that the chassis, which had proved a satisfactory combination on the new car for stock, also proved to be equally satisfactory when fitted with Mr.Davies's body, which goes to prove that in this case, where the body was looked upon as being the cause of all the trouble, it was in fact doing very little to contribute to it because, when fitted to another chassis, the complaint was eliminated. Referring to 18-EX and your praise of this car, it has for a long time been a matter of regret to me that you were still using this particular car because it has been generally recognised by those concerned that 18-EX is one of the very best P.II cars that has ever been produced, and it would have been much better if you had had a more standard representative car for your own use. Nevertheless I have in mind that quite recently you wrote complaining of the torque reactions and vibrations of this car at the lower speeds and have complained of booming as being unmistakeable at 65/75. | ||