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).
Report investigating the potential causes of burning exhaust valves on the Condor engine.
| Identifier | ExFiles\Box 40\6\ Scan005 | |
| Date | 9th September 1922 | |
| Rg.{Mr Rowledge} from Hs.{Lord Ernest Hives - Chair} X3585 Hs{Lord Ernest Hives - Chair}5/LG25. 9.22. CONDOR 1.A. X4418(struck through) X3585 With reference to the Air Ministry's report on the burning of the exhaust valves on the Condor engine. We are certainly not of the opinion that this could be caused by the defective fitting of induction pipe manifolds. Leakage in the induction pipe might be serious at small throttle openings but with full throttle or nearly full throttle openings, it would have to be a considerably bad leak to make any appreciable difference. In all our tests we have never been able to prove that weak mixtures can cause over-heated valves. A strong mixture of course will definitely prevent over-heating. In order to get sufficient temperature to fuse the material of the exhaust valve, our tests have shown that this can only be produced by either a pre-ignition or by failure of the exhaust valve to get rid of its heat - this latter may be caused by the water circulation being faulty or the fact that the exhaust valve is tight in its guide. We experienced a similar trouble on a Condor engine on the Hangar test & it occurred during the 50 hours test on the Condor. We were running the engine without supplementry top water pipes. We had trouble on two occasion with the exhaust valves sticking up and burning. When the new pipes were added, the trouble was overcome. We proved definitely that the fault at that time was caused by faulty circulation. | ||