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).
Throttle closing issues caused by carbon deposits and worn spindle bearings.
| Identifier | ExFiles\Box 1\3\ B001_X 93-page78 | |
| Date | 7th October 1926 guessed | |
| -5- Contd. (a) The effect of the gummy carbon deposit (a) is to prevent the throttle from closing fully if released slowly; if it is released quickly the throttle overcomes the resistance of the carbon, cuts through it and closes correctly; in this case the throttle sticks closed owing to the wedge effect of the throttle edge closing against the carbon deposit. (b) Wear in the throttle spindle bearings has the same ultimate effect of not allowing the throttle to close completely when released gently. The cause in this case is that the throttle, no longer located centrally by good spindle bearings, does not close centrally. The throttle closing spring is pulling the throttle out of its original central position, the result being that one edge of the butterfly valve comes into contact with its seating before the opposite edge, and the spring is not strong enough to afterwards centralise up the throttle if it is closed gently. If it is released quickly, however, the throttle will close. In both of these cases the amount the throttle is restrained from closing is extremely small, less than 0.5°, but it is ample to cause very bad firing in the silencer. The effect caused by badly worn spindle bearings would be overcome by the use of ball bearings; another advantage which could be gained by this means would be a reduction of air leaks which at present are very pronounced through the spindle bearings (it is assumed that the ball races will be enclosed by an airtight cap). Contd. | ||