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).
Engine explosions, their causes, and a comparison between Phantom and Silver Ghost models.
| Identifier | ExFiles\Box 38\4\ Scan096 | |
| Date | 7th October 1926 | |
| contd :- -3- lever is set to drive the car, consequently the range over which explosions can occur is relatively small. Our recommendations for reducing explosions to a minimum were given in Hs{Lord Ernest Hives - Chair}/AJLL/T7.10.26., we have no further recommendations at present. There is considerable variation between cars however - there is, even when carefully adjusted up and made to our recommendations. In every car, explosions are present under small throttle opening conditions but they vary in intensity, so that on some cars they are inaudible with the cutout closed. This difference we have proved is not due to carburation, induction system or exhaust system. The fault follows the engine itself: it is possible it may be due to differences in piston fit, ring leakage, and consequent crankcase dilution. Whatever the cause is, it is evident that the differences in engines made and tested within our limits is sufficient to produce variations in the degree of intensity of the bangs in the silencer. We are rather apt to compare the Phantom unfavourably with the Silver Ghost in this respect. While we agree that the earlier car had a better chance of not producing this effect due to superior governor operation and controls due to the different type of throttle used, we do not agree that it was in any way immune from it: our recollection is that when they did occur the explosions were extremely violent, more so than on the Phantom. Small explosions also occurred but were made less noticeable by the greater degree of silencing used. The Silver Ghost was contd :- | ||