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 sparking plugs fitted with electrodes coated with palladium, platinum and rhodium to reduce erosion caused by spark discharge.
| Identifier | ExFiles\Box 58\2\ Scan166 | |
| Date | 1st November 1933 | |
| WST V1812. H/l/war. Report No.R.A.E/E&I.818. November,1933. ROYAL AIRCRAFT ESTABLISHMENT, SOUTH FARNBOROUGH. Tests on sparking plugs fitted with electrodes coated with palladium, platinum and rhodium with the object of reducing erosion caused by spark discharge. R.A.E.Ref:- E&I/S.P.272/11. A.M.Ref:- 197703/32/R.D.E.3. 'D' 1. Introductory. It has been suggested that a coating of one or other of the rarer precious metals such as platinum, palladium or rhodium, on the electrodes of a sparking plug might prove beneficial in reducing erosion caused by the spark discharge. Three pairs of plugs having electrodes coated with the above mentioned materials were received from R.D.E.3. for test to determine whether any benefit would accrue from this form of protection. 2. Description of plugs. The following plugs were tested:- 2, Lodge Type A.2/1. with platinum coated electrodes. 2, K.L.G. Type V.7, one with palladium and the other with rhodium coated electrodes. 2, K.L.G. Type V.II ditto. The thickness of the coating on the electrodes was not known. 3. Laboratory tests. As a preliminary step, a direct comparison between the erosion resisting properties of electrodes made of pure nickel and nickel coated with platinum was made. A small spark gap was constructed having electrodes of these materials 0.1 inch diameter arranged at right angles to one another as shown on Fig.1. Six H.T. leads of positive polarity taken from a 12 cylinder magneto running at 2500 R.P.M. were connected to the spark gap which was shunted with a capacity of 250 m.mfds. in order to intensify the spark. The spark gap was at N.T.P. | ||