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).
Spark plug wear measurements by engine position and plug type.
| Identifier | ExFiles\Box 58\2\ Scan144 | |
| Date | 11th July 1934 | |
| -2- Hs{Lord Ernest Hives - Chair}/Wst.1/KW.11.7.34. Position in Type of Diam of Wear Engine Plug Electrode B31 K.L.G. .063 .037 744 B B41 " .065 .035 B51 " .057 .043 B61 " .063 .037 B1E Lodge .060 .040 X400B B2E " .085 .035 B3E " .078 .022 B4E " .074 .026 B5E " .070 .030 B6E " .063 .037 Average wear on inlet Plugs (K.L.G. 744B) .036" " " " exhaust " (Lodge X400B) .026" Hs{Lord Ernest Hives - Chair}/Wst. | ||