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).
Vibrations in the 25 HP model caused by the whirling of the propeller shaft at high speeds.
| Identifier | WestWitteringFiles\U\August1930-November1930\ Scan048 | |
| Date | 8th September 1930 | |
| To R.{Sir Henry Royce} From Hs.{Lord Ernest Hives - Chair} c. to Sk. c. to Mor. c. to E.{Mr Elliott - Chief Engineer} c. to Ds. c. to My. ORIGINAL Hs.{Lord Ernest Hives - Chair} 2/MJ. 8.9.30. 25 HP. VIBRATIONS. X. 634. X. 5340. We have proved definitely that one cause of the vibrations we get at high speeds on the 25 HP. is the whirling of the propeller shaft. We noticed when we were running the Experimental 25 HP. cars on Brooklands, that there was a very definite vibration at the maximum speeds - i.e. over 65 M.P.H. We have since tried running cars on the dynamometer and we find that on 12-G4 the whirling is alarming at 3500 engine revs. It is there on the new chassis, but not so pronounced. The propeller shaft on the Exp. car is slightly out of truth but as we know it was true when it was first fitted we believe it is the effect of whirling which has caused it to run out. We should be very glad to have a scheme of a stiffer propeller shaft which we could test out. Hs.{Lord Ernest Hives - Chair} | ||