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).
Conclusions of engine detonation tests, its effects on joint rings, and proposed future development.
| Identifier | ExFiles\Box 54\4\ Scan090 | |
| Date | 20th July 1933 | |
| -2- Hs {Lord Ernest Hives - Chair} /Ryce.5/MJ.20.7.33. Cont'd. {John DeLooze - Company Secretary} The apparent attack visible in the photograph on No.1 cyl. is due to oil which was inadvertently left on the part. CONCLUSIONS. The result of this test indicates that we cannot expect much relief from the destructive effects of detonation with the present D.T.D.134 at the higher ratings by any reasonable increase in the water flow through the cylinder head. The fact that the corresponding parts of other cylinders and the part of No.4 cylinder immediately adjacent to No.3 cylinder are completely unattacked shows that the trouble cannot be due to any local hot spot. The trouble from detonation is thought to be due to some distribution effect. Further evidence in favour of the distribution in place of the steam pocket theory is as follows :- (1) It was noticed when running the six cylinder unit not detonating that the exhaust flame from No.3 cyl. and to a lesser degree No.2 cylinder was slightly different from the others. (2) The scene of attack changes from the usual No.3 cyl. with the Kestrel engine to the end cylinders when Goshawk induction pipes are fitted. Hs {Lord Ernest Hives - Chair} /Yng.4/MJ.24.4.33, Hs {Lord Ernest Hives - Chair} /Ing.2/MJ.13.7.33. (3) Detonation is very susceptible to the mixture control. Tests now proceeding on the single cylinder unit show that the degree of detonation is only slightly susceptible to jacket temperature but is much more susceptible to mixture temperature. The susceptibility to jacket temperature appears to be that which would be expected from the change in mixture temperature brought about by the change in jacket temperature. JOINT RINGS. Attack on joint rings is confined almost entirely to the lower and the inner face of the ring which press against the liner (see sketch). The upper face in contact with the head remains almost entirely unaffected. The fact that the lower ring in this case was also entirely unaffected shows that the attack must be due to some products of partial combustion being forced by the intense local pressure to the ring surface and attacking it electrolytically. FURTHER DEVELOPMENT. Further tests are to be carried out with a later type of block and attempts are to be made to modify the distribution. Hs {Lord Ernest Hives - Chair} /H.R.Royce. | ||