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).
The test of a special sparking plug in Eagle and Falcon aero engines.
Identifier | ExFiles\Box 33\3\ Scan008 | |
Date | 26th June 1918 | |
X 1812a COPY. ----------------- 26th JUNE 1918. REPORT ON THE TEST OF SPECIAL SPARKING PLUG FIRST TEST. The Plug was placed in a Series 8 Eagle engine and run at 1850 Revs. per min. for 20 mins., no signs of pre-ignition was shown during the run, and the Plug would not soot up under any conditions of over oiling, although other plugs by two famous makers sooted up on the first signs of over oiling. SECOND TEST. The Plug was next put in a Falcon Series 1 engine, and run for 2 hours at 1800 Revs. per min. during which time it ran as perfectly as on the 400 H.P. Eagle, it did not soot up or pre-ignite. FINAL TEST. This Plug was dismantled and examined by the Foreman in Charge of the Test Houses, and found to be in perfect condition, it was then re-assembled and put in FALCON engine No.1323, Series 111, which had been on its 2nd Test and had burnt out a set of Aero Plugs by a certain famous maker; these plugs were burnt out one after another on the first three cylinders left hand side, which are the hottest cylinders on the FALCON. The engine was started up with the Plug in Cyl.No.1, and it ran for 10 mins. without any fault; but the plugs in Cyls.2 & 3 were pre-igniting badly by this time, and they were endangering the exhaust valves, because pre-ignition causes tremendous overheating of the cylinders, pistons, and valves, and if an engine is run for any time with plugs pre-igniting the result will be a crash. The engine was stopped for 10 mins. and the plug put in No.2 cylinder, when it ran perfectly, the cyl. showing no signs of overheating or pre-ignition. It was then put in No.3 cylinder, and run at 1800 Revs. for half an hour, during which time the Plug ran as well as ever, and when it was examined after the test, it was found to be in no way the worse for its severe trial, and it was voted by the Tester in Charge to be the best plug that they had ever had, and they hoped that it would be adopted as the Standard Plug for their engines. --------------------- AERO ENGINES PRODUCTION OFFICER. NOTE. You have succeeded in producing a Sparking Plug which is made of ordinary MILD STEEL, and which does more than the special Alloy Steel and Nickel Steel Plugs which are made by other makers. The particular construction of the plug accounts in a great measure for its efficiency. --------------------- | ||