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 from the Marine Aircraft Experimental Establishment on the unsuitability of soft aluminium sparking plug washers.
| Identifier | ExFiles\Box 42\4\ Scan029 | |
| Date | 1st December 1931 | |
| x3855 LBH{Mr Hall - Aero Design Engineer} F/EC/69. MARINE AIRCRAFT EXPERIMENTAL ESTABLISHMENT, FELIXSTOWE. REPORT NO. F/EC/69. HS{Lord Ernest Hives - Chair}, Pg SUBJECT: SPARKING PLUG WASHERS OF ALUMINIUM. "D" December, 1931. Tests have recently been made at this establishment on sparking plugs protected against corrosion by zinc coating. The tests were described and the results given in Report No. F/E/11, dated March 1931. For the purpose of these tests special plug washers of aluminium were used in order to avoid the electrolytic action which would normally be set up by the use of standard copper asbestos washers on zinc coated sparking plugs in a salt-laden atmosphere. The special aluminium washers supplied for the tests were hollow rings formed from aluminium sheet, and they were not filled with asbestos as is usual with copper washers of the same form. During the tests these washers proved to be too soft and pliable. A gas tight joint can be made with these washers if the plug is tightened down carefully, but if much pressure is exerted the washer is pushed out over part of its circumference and a leaky joint results. This effect is produced without applying abnormal loads to the plug spinner so that these washers cannot be regarded as suitable for use Stamp Text: AERONAUTICAL INSPECTION DIRECTORATE 19 JAN 1932 MESSRS. ROLLS. ROYCE. DERBY /in | ||