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).
Tests on standard, palladium, and rhodium coated K.L.G. Type VII plugs in a 'Pegasus' engine.
Identifier | ExFiles\Box 58\2\ Scan168 | |
Date | 1st November 1933 guessed | |
3. E&I.818. 5. Tests in "Pegasus" engine. Two K.L.G. Type VII plugs, one with palladium and the other with rhodium coated electrodes were fitted in No.6 and No.7 cylinders of a "Pegasus I.M.3. engine. Two new standard VII plugs were also fitted in the same cylinders in order to obtain comparative erosion data. The gaps of all four plugs were set at 0.013" and the engine was run at 2,200 R.P.M. on standard fuel D.T.D. 134. After running 14 hours 15 minutes the plugs were removed and the amount of erosion of the electrodes was measured. The following table shows the results: Test No.1. | Plug. | Cylinder No. | Initial Gap | Gap after 14 1/2 hrs. run. | Erosion. | |----------------------------------------|--------------|----------------------|----------------------------|----------------------| | "A" Standard VII "P" Palladium coated. | 6 | 0.013 in. 0.013 " | 0.020 in. 0.025 " | 0.007 in. 0.012 " | | "B" Standard VII "R" Rhodium coated. | 7 | 0.013 in. 0.013 " | 0.025 in. 0.025 " | 0.012 in. 0.012 " | These results show that erosion of the coated electrodes is certainly not any less than that of standard un-coated electrodes. After the above test the gaps of all four plugs were re-set to 0.012 inch and the plugs were replaced in the same cylinders for a further run. After completing 46 hours, making a total of 60 1/4 hours, the plugs were again removed for measurement of the erosion. The following table shows the results. Test No.2. | Plug. | Cylinder No. | Initial Gap | Gap after 46 hrs. run. | Erosion. | |----------------------------------------|--------------|----------------------|----------------------------|----------------------| | "A" Standard VII "P" Palladium coated. | 6 | 0.012 in 0.012 " | 0.027 in. 0.025 " | 0.015 in. 0.013 " | | "B" Standard VII "R" Rhodium coated. | 7 | 0.012 in 0.012 " | 0.027 in. 0.035 " | 0.015 in. 0.023 " | In this case, the erosion of the palladium coated electrode is approximately the same as that of the standard material whereas in the first test the palladium coated electrode was markedly inferior. Similarly, the erosion of the rhodium coated electrode and the standard electrode was the same on the first test but in the second test the rhodium | ||